Internet DRAFT - draft-clausen-lln-loadng
draft-clausen-lln-loadng
Network Working Group T. Clausen
Internet-Draft A. Colin de Verdiere
Intended status: Standards Track J. Yi
Expires: July 10, 2016 LIX, Ecole Polytechnique
A. Niktash
Maxim Integrated Products
Y. Igarashi
H. Satoh
Hitachi, Ltd., Yokohama Research
Laboratory
U. Herberg
Fujitsu Laboratories of America
C. Lavenu
EDF R&D
T. Lys
ERDF
J. Dean
Naval Research Laboratory
January 7, 2016
The Lightweight On-demand Ad hoc Distance-vector Routing Protocol - Next
Generation (LOADng)
draft-clausen-lln-loadng-14
Abstract
This document describes the Lightweight Ad hoc On-Demand - Next
Generation (LOADng) distance vector routing protocol, a reactive
routing protocol intended for use in Mobile Ad hoc NETworks (MANETs).
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. This document may not be modified,
and derivative works of it may not be created, except to format it
for publication as an RFC or to translate it into languages other
than English.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
Clausen, et al. Expires July 10, 2016 [Page 1]
Internet-Draft LOADng January 2016
This Internet-Draft will expire on July 10, 2016.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Terminology and Notation . . . . . . . . . . . . . . . . . . . 6
2.1. Message and Message Field Notation . . . . . . . . . . . . 6
2.2. Variable Notation . . . . . . . . . . . . . . . . . . . . 7
2.3. Other Notation . . . . . . . . . . . . . . . . . . . . . . 7
2.4. Terminology . . . . . . . . . . . . . . . . . . . . . . . 7
3. Applicability Statement . . . . . . . . . . . . . . . . . . . 8
4. Protocol Overview and Functioning . . . . . . . . . . . . . . 9
4.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.2. LOADng Routers and LOADng Interfaces . . . . . . . . . . . 11
4.3. Information Base Overview . . . . . . . . . . . . . . . . 11
4.4. Signaling Overview . . . . . . . . . . . . . . . . . . . . 12
5. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 13
5.1. Protocol and Port Numbers . . . . . . . . . . . . . . . . 13
5.2. Router Parameters . . . . . . . . . . . . . . . . . . . . 13
5.3. Interface Parameters . . . . . . . . . . . . . . . . . . . 14
5.4. Constants . . . . . . . . . . . . . . . . . . . . . . . . 15
6. Protocol Message Content . . . . . . . . . . . . . . . . . . . 15
6.1. Route Request (RREQ) Messages . . . . . . . . . . . . . . 15
6.2. Route Reply (RREP) Messages . . . . . . . . . . . . . . . 16
6.3. Route Reply Acknowledgement (RREP_ACK) Messages . . . . . 17
6.4. Route Error (RERR) Messages . . . . . . . . . . . . . . . 18
7. Information Base . . . . . . . . . . . . . . . . . . . . . . . 19
7.1. Routing Set . . . . . . . . . . . . . . . . . . . . . . . 19
7.2. Local Interface Set . . . . . . . . . . . . . . . . . . . 20
7.3. Blacklisted Neighbor Set . . . . . . . . . . . . . . . . . 20
7.4. Destination Address Set . . . . . . . . . . . . . . . . . 21
7.5. Pending Acknowledgment Set . . . . . . . . . . . . . . . . 21
8. LOADng Router Sequence Numbers . . . . . . . . . . . . . . . . 22
Clausen, et al. Expires July 10, 2016 [Page 2]
Internet-Draft LOADng January 2016
9. Route Maintenance . . . . . . . . . . . . . . . . . . . . . . 22
10. Unidirectional Link Handling . . . . . . . . . . . . . . . . . 24
10.1. Blacklist Usage . . . . . . . . . . . . . . . . . . . . . 24
11. Common Rules for RREQ and RREP Messages . . . . . . . . . . . 25
11.1. Identifying Invalid RREQ or RREP Messages . . . . . . . . 26
11.2. RREQ and RREP Message Processing . . . . . . . . . . . . . 27
12. Route Requests (RREQs) . . . . . . . . . . . . . . . . . . . . 30
12.1. RREQ Generation . . . . . . . . . . . . . . . . . . . . . 30
12.2. RREQ Processing . . . . . . . . . . . . . . . . . . . . . 31
12.3. RREQ Forwarding . . . . . . . . . . . . . . . . . . . . . 31
12.4. RREQ Transmission . . . . . . . . . . . . . . . . . . . . 32
13. Route Replies (RREPs) . . . . . . . . . . . . . . . . . . . . 32
13.1. RREP Generation . . . . . . . . . . . . . . . . . . . . . 32
13.2. RREP Processing . . . . . . . . . . . . . . . . . . . . . 33
13.3. RREP Forwarding . . . . . . . . . . . . . . . . . . . . . 34
13.4. RREP Transmission . . . . . . . . . . . . . . . . . . . . 34
14. Route Errors (RERRs) . . . . . . . . . . . . . . . . . . . . . 35
14.1. Identifying Invalid RERR Messages . . . . . . . . . . . . 36
14.2. RERR Generation . . . . . . . . . . . . . . . . . . . . . 36
14.3. RERR Processing . . . . . . . . . . . . . . . . . . . . . 37
14.4. RERR Forwarding . . . . . . . . . . . . . . . . . . . . . 38
14.5. RERR Transmission . . . . . . . . . . . . . . . . . . . . 38
15. Route Reply Acknowledgments (RREP_ACKs) . . . . . . . . . . . 39
15.1. Identifying Invalid RREP_ACK Messages . . . . . . . . . . 39
15.2. RREP_ACK Generation . . . . . . . . . . . . . . . . . . . 39
15.3. RREP_ACK Processing . . . . . . . . . . . . . . . . . . . 40
15.4. RREP_ACK Forwarding . . . . . . . . . . . . . . . . . . . 41
15.5. RREP_ACK Transmission . . . . . . . . . . . . . . . . . . 41
16. Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
16.1. Specifying New Metrics . . . . . . . . . . . . . . . . . . 41
17. Implementation Status . . . . . . . . . . . . . . . . . . . . 41
17.1. Implementation of Ecole Polytechnique . . . . . . . . . . 42
17.2. Implementation of Fujitsu Laboratories of America . . . . 42
17.3. Implementation of Hitachi Yokohama Research Laboratory
- 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
17.4. Implementation of Hitachi Yokohama Research Laboratory
-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
18. Security Considerations . . . . . . . . . . . . . . . . . . . 43
18.1. Security Threats . . . . . . . . . . . . . . . . . . . . . 44
18.1.1. Confidentiality . . . . . . . . . . . . . . . . . . . 44
18.1.2. Integrity . . . . . . . . . . . . . . . . . . . . . . 45
18.1.3. Channel Jamming and State Explosion . . . . . . . . . 46
18.1.4. Interaction with External Routing Domains . . . . . . 47
18.2. Integrity Protection . . . . . . . . . . . . . . . . . . . 47
18.2.1. Overview . . . . . . . . . . . . . . . . . . . . . . 48
18.2.2. Message Generation and Processing . . . . . . . . . . 50
19. LOADng Specific IANA Considerations . . . . . . . . . . . . . 52
19.1. Error Codes . . . . . . . . . . . . . . . . . . . . . . . 52
Clausen, et al. Expires July 10, 2016 [Page 3]
Internet-Draft LOADng January 2016
20. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 53
21. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 53
22. References . . . . . . . . . . . . . . . . . . . . . . . . . . 54
22.1. Normative References . . . . . . . . . . . . . . . . . . . 54
22.2. Informative References . . . . . . . . . . . . . . . . . . 54
Appendix A. Gateway Considerations . . . . . . . . . . . . . . . 56
Appendix B. LOADng Control Messages using RFC5444 . . . . . . . . 56
B.1. RREQ-Specific Message Encoding Considerations . . . . . . 56
B.2. RREP-Specific Message Encoding Considerations . . . . . . 58
B.3. RREP_ACK Message Encoding . . . . . . . . . . . . . . . . 60
B.4. RERR Message Encoding . . . . . . . . . . . . . . . . . . 61
B.5. RFC5444-Specific IANA Considerations . . . . . . . . . . . 62
B.5.1. Expert Review: Evaluation Guidelines . . . . . . . . 62
B.5.2. Message Types . . . . . . . . . . . . . . . . . . . . 63
B.6. RREQ Message-Type-Specific TLV Type Registries . . . . . . 63
B.7. RREP Message-Type-Specific TLV Type Registries . . . . . . 64
B.8. RREP_ACK Message-Type-Specific TLV Type Registries . . . . 67
B.9. RERR Message-Type-Specific TLV Type Registries . . . . . . 67
Appendix C. LOADng Control Packet Illustrations . . . . . . . . . 68
C.1. RREQ . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
C.2. RREP . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
C.3. RREP_ACK . . . . . . . . . . . . . . . . . . . . . . . . . 71
C.4. RERR . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Clausen, et al. Expires July 10, 2016 [Page 4]
Internet-Draft LOADng January 2016
1. Introduction
The Lightweight On-demand Ad hoc Distance-vector Routing Protocol -
Next Generation (LOADng) is a routing protocol, derived from AODV
[RFC3561] and extended for use in Mobile Ad hoc NETworks (MANETs).
As a reactive protocol, the basic operations of LOADng include
generation of Route Requests (RREQs) by a LOADng Router (originator)
for when discovering a route to a destination, forwarding of such
RREQs until they reach the destination LOADng Router, generation of
Route Replies (RREPs) upon receipt of an RREQ by the indicated
destination, and unicast hop-by-hop forwarding of these RREPs towards
the originator. If a route is detected to be broken, e.g., if
forwarding of a data packet to the recorded next hop on the route
towards the intended destination is detected to fail, a Route Error
(RERR) message is returned to the originator of that data packet to
inform the originator about the route breakage.
Compared to [RFC3561], LOADng is simplified as follows:
o Only the destination is permitted to respond to an RREQ;
intermediate LOADng Routers are explicitly prohibited from
responding to RREQs, even if they may have active routes to the
sought destination, and RREQ/RREP messages generated by a given
LOADng Router share a single unique, monotonically increasing
sequence number. This also eliminates Gratuitous RREPs while
ensuring loop freedom. The rationale for this simplification is
reduced complexity of protocol operation and reduced message
sizes.
o A LOADng Router does not maintain a precursor list, thus when
forwarding of a data packet to the recorded next hop on the route
to the destination fails, an RERR is sent only to the originator
of that data packet. The rationale for this simplification is an
assumption that few overlapping routes are in use concurrently in
a given network.
Compared to [RFC3561], LOADng is extended as follows:
o Optimized flooding is supported, reducing the overhead incurred by
RREQ generation and flooding. If no optimized flooding operation
is specified for a given deployment, classical flooding is used by
default.
o Different address lengths are supported - from full 16 octet IPv6
addresses over 8 octet EUI64 addresss [EUI64], 6 octet MAC
addresses and 4 octet IPv4 addresses to shorter 1 and 2 octet
addresses such as [RFC4944]. The only requirement is, that within
a given routing domain, all addresses are of the same address
Clausen, et al. Expires July 10, 2016 [Page 5]
Internet-Draft LOADng January 2016
length.
o Control messages are carried by way of the Generalized MANET
Packet/Message Format [RFC5444].
o Using [RFC5444], control messages can include TLV (Type-Length-
Value) elements, permitting protocol extensions to be developed.
o LOADng supports routing using arbitrary additive metrics, which
can be specified as extensions to this protocol.
2. Terminology and Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119].
Additionally, this document uses the notations in Section 2.1,
Section 2.2, and Section 2.3 and the terminology defined in
Section 2.4.
2.1. Message and Message Field Notation
LOADng Routers generate and process messages, each of which has a
number of distinct fields. For describing the protocol operation,
specifically the generation and processing of such messages, the
following notation is employed:
MsgType.field
where:
MsgType - is the type of message (e.g., RREQ or RREP);
field - is the field in the message (e.g., originator).
The different messages, their fields and their meaning are described
in Section 6. The encoding of messages for transmission by way of
[RFC5444] packets/messages is described in Appendix B, and Appendix C
illustrates the bit layout of LOADng control messages.
The motivation for separating the high-level messages and their
content from the low-level encoding and frame format for transmission
is to allow discussions of the protocol logic to be separated from
the message encoding and frame format - and, to support different
frame formats.
Clausen, et al. Expires July 10, 2016 [Page 6]
Internet-Draft LOADng January 2016
2.2. Variable Notation
Variables are introduced into the specification solely as a means to
clarify the description. The following notation is used:
MsgType.field - If "field" is a field in the message MsgType, then
MsgType.field is also used to represent the value of that field.
bar - A variable (not prepended by MsgType), usually obtained
through calculations based on the value(s) of element(s).
2.3. Other Notation
This document uses the following additional notational conventions:
a := b An assignment operator, whereby the left side (a) is
assigned the value of the right side (b).
c = d A comparison operator, returning TRUE if the value of the
left side (c) is equal to the value of the right side (d).
2.4. Terminology
This document uses the following terminology:
LOADng Router - A router that implements this routing protocol. A
LOADng Router is equipped with at least one, and possibly more,
LOADng Interfaces.
LOADng Interface - A LOADng Router's attachment to a communications
medium, over which it receives and generates control messages,
according to this specification. A LOADng Interface is assigned
one or more addresses.
Link - A link between two LOADng Interfaces exists if either can
receive control messages, according to this specification, from
the other.
Message - The fundamental entity carrying protocol information, in
the form of address objects and TLVs.
Link Metric - The cost (weight) of a link between a pair of LOADng
Interfaces.
Route Metric - The sum of the Link Metrics for the links that an
RREQ or RREP has crossed.
Clausen, et al. Expires July 10, 2016 [Page 7]
Internet-Draft LOADng January 2016
Network Address - A layer 3 IP address plus an associated prefix
length. This may be an address with an associated maximum prefix
length or an address prefix including a prefix length. A network
address thus represents a range of IP addresses.
3. Applicability Statement
LOADng is a reactive MANET protocol, i.e., routes are discovered only
when a data packet is sent by a router (e.g., on behalf of an
attached host), and when the router has no route for this
destination. In that case, the router floods Route Requests (RREQ)
throughout the network for discovering the destination. Reactive
protocols require state only for the routes currently in use,
contrary to proactive protocols, which periodically send control
traffic and store routes to all destinations in the network. As
MANETs are often operated on wireless channels, flooding RREQs may
lead to frame collisions and therefore data loss. Moreover, each
transmission on a network interface consumes energy, reducing the
life-time of battery-driven routers. Consequently, in order to
reduce the amount of control traffic, LOADng (and in general reactive
protocols) are most suitable under the following constraints:
o Few concurrent traffic flows in the network (i.e., traffic flows
only between few sources and destinations);
o Little data traffic overall, and therefore the traffic load from
periodic signaling (for proactive protocols) is greater than the
traffic load from flooding RREQs (for reactive protocols);
o State requirements on the router are very stringent, i.e., it is
beneficial to store only few routes on a router.
In these specific use cases, reactive MANET protocols have shown to
be beneficial, and may be preferable over the more general use case
of proactive MANET protocols.
Specifically, the applicability of LOADng is determined by its
characteristics, which are that this protocol:
o Is a reactive routing protocol for Mobile Ad hoc NETworks
(MANETs).
o Is designed to work in networks with dynamic topology in which the
links may be lossy due to collisions, channel instability, or
movement of routers.
o Supports the use of optimized flooding for RREQs.
Clausen, et al. Expires July 10, 2016 [Page 8]
Internet-Draft LOADng January 2016
o Enables any LOADng Router to discover bi-directional routes to
destinations in the routing domain, i.e., to any other LOADng
Router, as well as hosts or networks attached to that LOADng
Router, in the same routing domain.
o Supports addresses of any length with integral number of octets,
from 16 octets to a single octet.
o Is layer-agnostic, i.e., may be used at layer 3 as a "route over"
routing protocol, or at layer 2 as a "mesh under" routing
protocol.
o Supports per-destination route maintenance; if a destination
becomes unreachable, rediscovery of that single (bi-directional)
route is performed, without need for global topology
recalculation.
4. Protocol Overview and Functioning
The objective of this protocol is for each LOADng Router to,
independently:
o Discover a bi-directional route to any destination in the network.
o Establish a route only when there is data traffic to be sent along
that route.
o Maintain a route only for as long as there is data traffic being
sent along that route.
o Generate control traffic based on network events only: when a new
route is required, or when an active route is detected broken.
Specifically, this protocol does not require periodic signaling.
4.1. Overview
These objectives are achieved, for each LOADng Router, by performing
the following tasks:
o When having a data packet to deliver to a destination, for which
no tuple in the routing set exists and where the data packet
source is local to that LOADng Router (i.e., is an address in the
Local Interface Set or Destination Address Set of that LOADng
Router), generate a Route Request (RREQ) encoding the destination
address, and transmit this RREQ over all of its LOADng Interfaces.
o Upon receiving an RREQ, insert or refresh a tuple in the Routing
Set, recording a route towards the originator address from the
Clausen, et al. Expires July 10, 2016 [Page 9]
Internet-Draft LOADng January 2016
RREQ, as well as to the neighbor LOADng Router from which the RREQ
was received. This will install the Reverse Route (towards the
originator address from the RREQ).
o Upon receiving an RREQ, inspect the indicated destination address:
* If that address is an address in the Destination Address Set or
in the Local Interface Set of the LOADng Router, generate a
Route Reply (RREP), which is unicast in a hop-by-hop fashion
along the installed Reverse Route.
* If that address is not an address in the Destination Address
Set or in the Local Interface Set of the LOADng Router,
consider the RREQ as a candidate for forwarding.
o When an RREQ is considered a candidate for forwarding, retransmit
it according to the flooding operation, specified for the network.
o Upon receiving an RREP, insert or refresh a tuple in the Routing
Set, recording a route towards the originator address from the
RREP, as well as to the neighbor LOADng Router, from which that
RREP was received. This will install the Forward Route (towards
the originator address from the RREP). The originator address is
either an address from the Local Interface Set of the LOADng
Router, or an address from its Destination Address Set (i.e., an
address of a host attached to that LOADng Router).
o Upon receiving an RREP, forward it, as unicast, to the recorded
next hop along the corresponding Reverse Route until the RREP
reaches the LOADng Router that has the destination address from
the RREP in its Local Interface Set or Destination Address Set.
o When forwarding an RREQ or RREP, update the route metric, as
contained in that RREQ or RREP message.
A LOADng Router generating an RREQ specifies which metric type it
desires. Routers receiving an RREQ will process it and update route
metric information in the RREQ according to that metric, if they can.
All LOADng Routers, however, will update information in the RREQ so
as to be able to support a "hop-count" default metric. If a LOADng
Router is not able to understand the metric type, specified in an
RREQ, it will update the route metric value to its maximum value, so
as to ensure that this is indicated to the further recipients of the
RREQ. Once the route metric value is set to its maximum value, no
LOADng Router along the path towards the destination may change the
value.
Clausen, et al. Expires July 10, 2016 [Page 10]
Internet-Draft LOADng January 2016
4.2. LOADng Routers and LOADng Interfaces
A LOADng Router has a set of at least one, and possibly more, LOADng
Interfaces. Each LOADng Interface:
o Is configured with one or more addresses.
o Has a number of interface parameters.
In addition to a set of LOADng Interfaces as described above, each
LOADng Router:
o Has a number of router parameters.
o Has an Information Base.
o Generates and processes RREQ, RREP, RREP_ACK and RERR messages,
according to this specification.
4.3. Information Base Overview
Necessary protocol state is recorded by way of five information sets:
the "Routing Set", the "Local Interface Set", the "Blacklisted
Neighbor Set", the "Destination Address Set", and the "Pending
Acknowledgment Set".
The Routing Set contains tuples, each representing the next-hop on,
and the metric of, a route towards a destination address.
Additionally, the Routing Set records the sequence number of the last
message, received from the destination. This information is
extracted from the message (RREQ or RREP) that generated the tuple so
as to enable routing. The routing table is to be updated using this
Routing Set. (A LOADng Router may choose to use any or all
destination addresses in the Routing Set to update the routing table,
this selection is outside the scope of this specification.)
The Local Interface Set contains tuples, each representing a local
LOADng Interface of the LOADng Router. Each tuple contains a list of
one or more addresses of that LOADng Interface.
The Blacklisted Neighbor Set contains tuples representing neighbor
LOADng Interface addresses of a LOADng Router with which
unidirectional connectivity has been recently detected.
The Destination Address Set contains tuples representing addresses,
for which the LOADng Router is responsible, i.e., addresses of this
LOADng Router, or of hosts and networks directly attached to this
LOADng Router and which use it to connect to the routing domain.
Clausen, et al. Expires July 10, 2016 [Page 11]
Internet-Draft LOADng January 2016
These addresses may in particular belong to devices which do not
implement LOADng, and thus cannot process LOADng messages. A LOADng
Router provides connectivity to these addresses by generating RREPs
in response to RREQs directed towards them.
The Pending Acknowledgment Set contains tuples, representing
transmitted RREPs for which an RREP_ACK is expected, but where this
RREP_ACK has not yet been received.
The Routing Set, the Blacklisted Neighbor Set and the Pending
Acknowledgment Set are updated by this protocol. The Local Interface
Set and the Destination Address Set are used, but not updated by this
protocol.
4.4. Signaling Overview
This protocol generates and processes the following routing messages:
Route Request (RREQ) - Generated by a LOADng Router when it has a
data packet to deliver to a given destination, where the data
packet source is local to that LOADng Router (i.e., is an address
in the Local Interface Set or Destination Address Set of that
LOADng Router), but where it does not have an available tuple in
its Routing Set indicating a route to that destination. An RREQ
contains:
* The (destination) address to which a Forward Route is to be
discovered by way of soliciting the LOADng Router with that
destination address in its Local Interface Set or in its
Destination Address Set to generate an RREP.
* The (originator) address for which a Reverse Route is to be
installed by RREQ forwarding and processing, i.e., the source
address of the data packet which triggered the RREQ generation.
* The sequence number of the LOADng Router, generating the RREQ.
An RREQ is flooded through the network, according to the flooding
operation specified for the network.
Route Reply (RREP) - Generated as a response to an RREQ by the
LOADng Router which has the address (destination) from the RREQ in
its Local Interface Set or in its Destination Address Set. An RREP
is sent in unicast towards the originator of that RREQ. An RREP
contains:
* The (originator) address to which a Forward Route is to be
installed when forwarding the RREP.
Clausen, et al. Expires July 10, 2016 [Page 12]
Internet-Draft LOADng January 2016
* The (destination) address towards which the RREP is to be sent.
More precisely, the destination address determines the unicast
route which the RREP follows.
* The sequence number of the LOADng Router, generating the RREP.
Route Reply Acknowledgment (RREP_ACK) - Generated by a LOADng Router
as a response to an RREP, in order to signal to the neighbor that
transmitted the RREP that the RREP was successfully received.
Receipt of an RREP_ACK indicates that the link between these two
neighboring LOADng Routers is bidirectional. An RREP_ACK is
unicast to the neighbor from which the RREP has arrived, and is
not forwarded. RREP_ACKs are generated only in response to an
RREP which, by way of a flag, has explicitly indicated that an
RREP_ACK is desired.
Route Error (RERR) - Generated by a LOADng Router when a link on an
active route to a destination is detected as broken by way of
inability to forward a data packet towards that destination. An
RERR is unicast to the source of the undeliverable data packet.
5. Protocol Parameters
The following parameters and constants are used in this
specification.
5.1. Protocol and Port Numbers
When using LOADng as an IP routing protocol, the considerations of
[RFC5498] apply.
5.2. Router Parameters
NET_TRAVERSAL_TIME - is the maximum time that a RREQ message is
expected to take when traversing from one end of the network to
the other, with the consideration of RREQ_MAX_JITTER.
RREQ_RETRIES - is the maximum number of subsequent RREQs that a
particular LOADng Router may generate in order to discover a route
to a destination, before declaring that destination unreachable.
RREQ_MIN_INTERVAL - is the minimal interval (in milliseconds) of
RREQs that a particular LOADng Router is allowed to send.
R_HOLD_TIME - is the minimum time a Routing Tuple SHOULD be kept in
the Routing Set after it was last refreshed.
Clausen, et al. Expires July 10, 2016 [Page 13]
Internet-Draft LOADng January 2016
MAX_DIST - is the value representing the maximum possible metric
(R_metric field).
B_HOLD_TIME - is the time during which the link between the neighbor
LOADng Router and this LOADng Router MUST be considered as non-
bidirectional, and that therefore RREQs received from that
neighbor LOADng Router MUST be ignored during that time
(B_HOLD_TIME). B_HOLD_TIME should be greater than 2 x
NET_TRAVERSAL_TIME x RREQ_RETRIES, to ensure that subsequent RREQs
will reach the destination via a route, excluding the link to the
blacklisted neighbor.
MAX_HOP_LIMIT - is the maximum limit of the number of hops that
LOADng routing messages are allowed to traverse.
5.3. Interface Parameters
Different LOADng Interfaces (on the same or on different LOADng
Routers) MAY employ different interface parameter values and MAY
change their interface parameter values dynamically. A particular
case is where all LOADng Interfaces on all LOADng Routers within a
given LOADng routing domain employ the same set of interface
parameter values.
RREQ_MAX_JITTER - is the default value of MAXJITTER used in
[RFC5148] for RREQ messages forwarded by this LOADng Router on
this interface.
RREP_ACK_REQUIRED - is a boolean flag, which indicates (if set) that
the LOADng Router is configured to expect that each RREP it sends
be confirmed by an RREP_ACK, or, (if cleared) that no RREP_ACK is
expected for this interface.
USE_BIDIRECTIONAL_LINK_ONLY - is a boolean flag, which indicates if
the LOADng Router only uses verified bi-directional links for data
packet forwarding on this interface. It is set by default. If
cleared, then the LOADng Router can use links which have not been
verified to be bi-directional on this interface.
RREP_ACK_TIMEOUT - is the minimum amount of time after transmission
of an RREP, that a LOADng Router SHOULD wait for an RREP_ACK from
a neighbor LOADng Router, before considering the link to this
neighbor to be unidirectional.
Clausen, et al. Expires July 10, 2016 [Page 14]
Internet-Draft LOADng January 2016
5.4. Constants
MAX_HOP_COUNT - is the maximum number of hops as representable by
the encoding that is used (e.g., 255 when using [RFC5444]). It
SHOULD NOT be used to limit the scope of a message; the router
parameter MAX_HOP_LIMIT can be used to limit the scope of a LOADng
routing message.
6. Protocol Message Content
The protocol messages, generated and processed by LOADng, are
described in this section using the notational conventions described
in Section 2. The encoding of messages for transmission by way of
[RFC5444] packets/messages is described in Appendix B, and Appendix C
illustrates the bit layout of a selection of LOADng control messages.
Unless stated otherwise, the message fields described below are set
by the LOADng Router that generates the message, and MUST NOT be
changed by intermediate LOADng Routers.
6.1. Route Request (RREQ) Messages
A Route Request (RREQ) message has the following fields:
RREQ.addr-length is an unsigned integer field, encoding the length
of the originator and destination addresses as follows:
RREQ.addr-length := the length of an address in octets - 1
RREQ.seq-num is an unsigned integer field, containing the sequence
number (see Section 8) of the LOADng Router, generating the RREQ
message.
RREQ.metric-type is an unsigned integer field and specifies the type
of metric requested by this RREQ.
RREQ.route-metric is a unsigned integer field, of length defined by
RREQ.metric-type, which specifies the route metric of the route
(the sum of the link metrics of the links), through which this
RREQ has traveled.
RREQ.hop-count is an unsigned integer field and specifies the total
number of hops which the message has traversed from the
RREQ.originator.
RREQ.hop-limit is an unsigned integer field and specifies the number
of hops that the message is allowed to traverse.
Clausen, et al. Expires July 10, 2016 [Page 15]
Internet-Draft LOADng January 2016
RREQ.originator is an identifier of RREQ.addr-length + 1 octets,
specifying the address of the LOADng Interface over which this
RREQ was generated, and to which a route (the "reverse route") is
supplied by this RREQ. In case the message is generated by a
LOADng Router on behalf of an attached host, RREQ.originator
corresponds to an address of that host, otherwise it corresponds
to an address of the sending LOADng Interface of the LOADng
Router.
RREQ.destination is an identifier of RREQ.addr-length + 1 octets,
specifying the address to which the RREQ should be sent, i.e., the
destination address for which a route is sought.
The following fields of an RREQ message are immutable, i.e., they
MUST NOT be changed during processing or forwarding of the message:
RREQ.addr-length, RREQ.seq-num, RREQ.originator, and
RREQ.destination.
The following fields of an RREQ message are mutable, i.e., they will
be changed by intermediate routers during processing or forwarding,
as specified in Section 12.2 and Section 12.3: RREQ.metric-type,
RREQ.route-metric, RREQ.hop-limit, and RREQ.hop-count.
Any additional field that is added to the message by an extension to
this protocol, e.g., by way of TLVs, MUST be considered immutable,
unless the extension specifically defines the field as mutable.
6.2. Route Reply (RREP) Messages
A Route Reply (RREP) message has the following fields:
RREP.addr-length is an unsigned integer field, encoding the length
of the originator and destination addresses as follows:
RREP.addr-length := the length of an address in octets - 1
RREP.seq-num is an unsigned integer field, containing the sequence
number (see Section 8) of the LOADng Router, generating the RREP
message.
RREP.metric-type is an unsigned integer field and specifies the type
of metric, requested by this RREP.
RREP.route-metric is a unsigned integer field, of length defined by
RREP.metric-type, which specifies the route metric of the route
(the sum of the link metrics of the links) through which this RREP
has traveled.
Clausen, et al. Expires July 10, 2016 [Page 16]
Internet-Draft LOADng January 2016
RREP.ackrequired is a boolean flag which, when set ('1'), at least
one RREP_ACK MUST be generated by the recipient of an RREP if the
RREP is successfully processed. When cleared ('0'), an RREP_ACK
MUST NOT be generated in response to processing of the RREP.
RREP.hop-count is an unsigned integer field and specifies the total
number of hops which the message has traversed from
RREP.originator to RREP.destination.
RREP.hop-limit is an unsigned integer field and specifies the number
of hops that the message is allowed to traverse.
RREP.originator is an identifier of RREP.addr-length + 1 octets,
specifying the address for which this RREP was generated, and to
which a route (the "forward route") is supplied by this RREP. In
case the message is generated on a LOADng Router on behalf of an
attached host, RREP.originator corresponds to an address of that
host, otherwise it corresponds to an address of the LOADng
Interface of the LOADng Router, over which the RREP was generated.
RREP.destination is an identifier of RREP.addr-length + 1 octets,
specifying the address to which the RREP should be sent. (I.e.,
this address is equivalent to RREQ.originator of the RREQ that
triggered the RREP.)
The following fields of an RREP message are immutable, i.e., they
MUST NOT be changed during processing or forwarding of the message:
RREP.addr-length, RREP.seq-num, RREP.originator, and
RREP.destination.
The following fields of an RREP message are mutable, i.e., they will
be changed by intermediate routers during processing or forwarding,
as specified in Section 13.2 and Section 13.3: RREP.metric-type,
RREP.route-metric, RREP.ackrequired, RREP.hop-limit, and RREP.hop-
count.
Any additional field that is added to the message by an extension to
this protocol, e.g., by way of TLVs, MUST be considered immutable,
unless the extension specifically defines the field as mutable.
6.3. Route Reply Acknowledgement (RREP_ACK) Messages
A Route Reply Acknowledgement (RREP_ACK) message has the following
fields:
Clausen, et al. Expires July 10, 2016 [Page 17]
Internet-Draft LOADng January 2016
RREP_ACK.addr-length is an unsigned integer field, encoding the
length of the destination and originator addresses as follows:
RREP_ACK.addr-length := the length of an address in octets - 1
RREP_ACK.seq-num is an unsigned integer field and contains the value
of RREP.seq-num from the RREP for which this RREP_ACK is sent.
RREP_ACK.destination is an identifier of RREP_ACK.addr-length + 1
octets and contains the value of the RREP.originator field from
the RREP for which this RREP_ACK is sent.
RREP_ACK messages are sent only across a single link and are never
forwarded.
6.4. Route Error (RERR) Messages
A Route Error (RERR) message has the following fields:
RERR.addr-length is an unsigned integer field, encoding the length
of RERR.destination and RERR.unreachableAddress, as follows:
RERR.addr-length := the length of an address in octets - 1
RERR.errorcode is an unsigned integer field and specifies the reason
for the error message being generated, according to Table 1.
RERR.unreachableAddress is an identifier of RERR.addr-length + 1
octets, specifying an address, which has become unreachable, and
for which an error is reported by way of this RERR message.
RERR.originator is an identifier of RERR.addr-length + 1 octets,
specifying the address of the LOADng Interface over which this
RERR was generated by a LOADng Router.
RERR.destination is an identifier of RERR.address-length + 1 octets,
specifying the destination address of this RERR message.
RERR.destination is, in general, the source address of a data
packet, for which delivery to RERR.unreachableAddress failed, and
the unicast destination of the RERR message is the LOADng Router
which has RERR.destination listed in a Local Interface Tuple or in
a Destination Address Tuple.
RERR.hop-limit is an unsigned integer field and specifies the number
of hops that the message is allowed to traverse.
The following fields of an RERR message are immutable, i.e., they
MUST NOT be changed during processing or forwarding of the message:
Clausen, et al. Expires July 10, 2016 [Page 18]
Internet-Draft LOADng January 2016
RERR.addr-length, RERR.errorcode, RERR.unreachableAddress,
RERR.originator and RERR.destination.
The following fields of an RERR message are mutable, i.e., they will
be changed by intermediate routers during processing or forwarding,
as specified in Section 14.3 and Section 14.4: RERR.hop-limit.
Any additional field that is added to the message by an extension to
this protocol, e.g., by way of TLVs, MUST be considered immutable,
unless the extension specifically defines the field as mutable.
7. Information Base
Each LOADng Router maintains an Information Base, containing the
information sets necessary for protocol operation, as described in
the following sections. The organization of information into these
information sets is non-normative, given so as to facilitate
description of message generation, forwarding and processing rules in
this specification. An implementation may choose any representation
or structure for when maintaining this information.
7.1. Routing Set
The Routing Set records the next hop on the route to each known
destination, when such a route is known. It consists of Routing
Tuples:
(R_dest_addr, R_next_addr, R_metric, R_metric_type, R_hop_count,
R_seq_num, R_bidirectional, R_local_iface_addr, R_valid_time)
where:
R_dest_addr - is the address of the destination, either an address
of a LOADng Interface of a destination LOADng Router, or an
address of an interface reachable via the destination LOADng
Router, but which is outside the routing domain.
R_next_addr - is the address of the "next hop" on the selected route
to the destination.
R_metric - is the metric associated with the selected route to the
destination with address R_dest_addr.
R_metric_type - specifies the metric type for this Routing Tuple -
in other words, how R_metric is defined and calculated.
Clausen, et al. Expires July 10, 2016 [Page 19]
Internet-Draft LOADng January 2016
R_hop_count - is the hop count of the selected route to the
destination with address R_dest_addr.
R_seq_num - is the value of the RREQ.seq-num or RREP.seq-num field
of the RREQ or RREP which installed or last updated this tuple.
For the Routing Tuples installed by previous hop information of
RREQ or RREP, R_seq_num MUST be set to -1.
R_bidirectional - is a boolean flag, which specifies if the Routing
Tuple is verified as representing a bi-directional route. Data
traffic SHOULD only be routed through a routing tuple with
R_bidirectional flag equals TRUE, unless the LOADng Router is
configured as accepting routes without bi-directionality
verification explicitly by setting USE_BIDIRECTIONAL_LINK_ONLY to
FALSE of the interface with R_local_iface_address.
R_local_iface_addr - is an address of the local LOADng Interface,
through which the destination can be reached.
R_valid_time - specifies the time until which the information
recorded in this Routing Tuple is considered valid.
7.2. Local Interface Set
A LOADng Router's Local Interface Set records its local LOADng
Interfaces. It consists of Local Interface Tuples, one per LOADng
Interface:
(I_local_iface_addr_list)
where:
I_local_iface_addr_list - is an unordered list of the network
addresses of this LOADng Interface.
The implementation MUST initialize the Local Interface Set with at
least one tuple containing at least one address of an LOADng
Interface. The Local Interface Set MUST be updated if there is a
change of the LOADng Interfaces of a LOADng Router (i.e., a LOADng
Interface is added, removed or changes addresses).
7.3. Blacklisted Neighbor Set
The Blacklisted Neighbor Set records the neighbor LOADng Interface
addresses of a LOADng Router, with which connectivity has been
detected to be unidirectional. Specifically, the Blacklisted
Neighbor Set records neighbors from which an RREQ has been received
(i.e., through which a Forward Route would possible) but to which it
Clausen, et al. Expires July 10, 2016 [Page 20]
Internet-Draft LOADng January 2016
has been determined that it is not possible to communicate (i.e.,
forwarding Route Replies via this neighbor fails, rendering
installing the Forward Route impossible). It consists of Blacklisted
Neighbor Tuples:
(B_neighbor_address, B_valid_time)
where:
B_neighbor_address - is the address of the blacklisted neighbor
LOADng Interface.
B_valid_time - specifies the time until which the information
recorded in this tuple is considered valid.
7.4. Destination Address Set
The Destination Address Set records addresses, for which a LOADng
Router will generate RREPs in response to received RREQs, in addition
to its own LOADng Interface addresses (as listed in the Local
Interface Set). The Destination Address Set thus represents those
destinations (i.e., hosts), for which this LOADng Router is providing
connectivity. It consists of Destination Address Tuples:
(D_address)
where:
D_address - is the address of a destination (a host or a network),
attached to this LOADng Router and for which this LOADng Router
provides connectivity through the routing domain.
The Destination Address Set is used for generating signaling, but is
not itself updated by signaling specified in this document. Updates
to the Destination Address Set are due to changes of the environment
of a LOADng Router - hosts or external networks being connected to or
disconnected from a LOADng Router. The Destination Address Set may
be administrationally provisioned, or provisioned by external
protocols.
7.5. Pending Acknowledgment Set
The Pending Acknowledgment Set contains information about RREPs which
have been transmitted with the RREP.ackrequired flag set, and for
which an RREP_ACK has not yet been received. It consists of Pending
Acknowledgment Tuples:
(P_next_hop, P_originator, P_seq_num,
Clausen, et al. Expires July 10, 2016 [Page 21]
Internet-Draft LOADng January 2016
P_ack_received, P_ack_timeout)
where:
P_next_hop - is the address of the neighbor LOADng Interface to
which the RREP was sent.
P_originator - is the address of the originator of the RREP.
P_seq_num - is the RREP.seq-num field of the sent RREP.
P_ack_received - is a boolean flag, which specifies the tuple has
been acknowledged by a corresponding RREP_ACK message. The
default value is FALSE.
P_ack_timeout - is the time after which the tuple MUST be expired.
8. LOADng Router Sequence Numbers
Each LOADng Router maintains a single sequence number, which must be
included in each RREQ or RREP message it generates. Each LOADng
Router MUST make sure that no two messages (both RREQ and RREP) are
generated with the same sequence number, and MUST generate sequence
numbers such that these are monotonically increasing. This sequence
number is used as information for when comparing routes to the LOADng
Router having generated the message.
However, with a limited number of bits for representing sequence
numbers, wrap-around (that the sequence number is incremented from
the maximum possible value to zero) can occur. To prevent this from
interfering with the operation of the protocol, the following MUST be
observed. The term MAXVALUE designates in the following the largest
possible value for a sequence number. The sequence number S1 is said
to be "greater than" (denoted '>') the sequence number S2 if:
S2 < S1 AND S1 - S2 <= MAXVALUE/2 OR
S1 < S2 AND S2 - S1 > MAXVALUE/2
9. Route Maintenance
Tuples in the Routing Set are maintained by way of five different
mechanisms:
o RREQ/RREP exchange, specified in Section 12 and Section 13.
o Data traffic delivery success.
Clausen, et al. Expires July 10, 2016 [Page 22]
Internet-Draft LOADng January 2016
o Data traffic delivery failure.
o External signals indicating that a tuple in the Routing Set needs
updating.
o Information expiration.
Routing Tuples in the Routing Set contain a validity time, which
specifies the time until which the information recorded in this tuple
is considered valid. After this time, the information in such tuples
is to be considered as invalid, for the processing specified in this
document.
Routing Tuples for actively used routes (i.e., routes via which
traffic is currently transiting) SHOULD NOT be removed, unless there
is evidence that they no longer provide connectivity - i.e., unless a
link on that route has broken.
To this end, one or more of the following mechanisms (non-exhaustive
list) MAY be used:
o If a lower layer mechanism provides signals, such as when delivery
to a presumed neighbor LOADng Router fails, this signal MAY be
used to indicate that a link has broken, trigger early expiration
of a Routing Tuple from the Routing Set, and to initiate Route
Error Signaling (see Section 14). Conversely, absence of such a
signal when attempting delivery MAY be interpreted as validation
that the corresponding Routing Tuple(s) are valid, and their
R_valid_time refreshed correspondingly. Note that when using such
a mechanism, care should be taken to prevent that an intermittent
error (e.g., an incidental wireless collision) triggers corrective
action and signaling. This depends on the nature of the signals,
provided by the lower layer, but can include the use of a
hysteresis function or other statistical mechanisms.
o Conversely, for each successful delivery of a packet to a neighbor
or a destination, if signaled by a lower layer or a transport
mechanism, or each positive confirmation of the presence of a
neighbor by way of an external neighbor discovery protocol, MAY be
interpreted as validation that the corresponding Routing Tuple(s)
are valid, and their R_valid_time refreshed correspondingly. Note
that when refreshing a Routing Tuple corresponding to a
destination of a data packet, the Routing Tuple corresponding to
the next hop toward that destination SHOULD also be refreshed.
Furthermore, a LOADng Router may experience that a route currently
used for forwarding data packets is no longer operational, and must
act to either rectify this situation locally (Section 13) or signal
Clausen, et al. Expires July 10, 2016 [Page 23]
Internet-Draft LOADng January 2016
this situation to the source of the data packets for which delivery
was unsuccessful (Section 14).
If a LOADng Router fails to deliver a data packet to a next-hop, it
MUST generate an RERR message, as specified in Section 14.
10. Unidirectional Link Handling
Each LOADng Router MUST monitor the bidirectionality of the links to
its neighbors and set the R_bidirectional flag of related routing
tuples when processing Route Replies (RREP). To this end, one or
more of the following mechanisms MAY be used (non exhaustive list):
o If a lower layer mechanism provides signals, such as when delivery
to a presumed neighbor LOADng Router fails, this signal MAY be
used to detect that a link to this neighbor is broken or is
unidirectional; the LOADng Router MUST then blacklist the neighbor
(see Section 10.1).
o If a mechanism such as NDP [RFC4861] is available, the LOADng
Router MAY use it.
o A LOADng Router MAY use a neighborhood discovery mechanism with
bidirectionality verification, such as NHDP [RFC6130].
o RREP_ACK message exchange, as described in Section 15.
o Upper-layer mechanisms, such as transport-layer acknowledgments,
MAY be used to detect unidirectional or broken links.
When a LOADng Router detects, via one of these mechanisms, that a
link to a neighbor LOADng Router is unidirectional or broken, the
LOADng Router MUST blacklist this neighbor (see Section 10.1).
Conversely, if a LOADng Router detects via one of these mechanisms
that a previously blacklisted LOADng Router has a bidirectional link
to this LOADng Router, it MAY remove it from the blacklist before the
B_valid_time of the corresponding tuple.
10.1. Blacklist Usage
The Blacklist is maintained according to Section 7.3. When an
interface of neighbor LOADng Router is detected to have a
unidirectional link to the LOADng Router, it is blacklisted, i.e., a
tuple (B_neighbor_address, B_valid_time) is created thus:
o B_neighbor_address := the address of the blacklisted neighbor
LOADng Router interface
Clausen, et al. Expires July 10, 2016 [Page 24]
Internet-Draft LOADng January 2016
o B_valid_time := current_time + B_HOLD_TIME
When a neighbor LOADng Router interface is blacklisted, i.e., when
there is a corresponding (B_neighbor_address, B_valid_time) tuple in
the Blacklisted Neighbor Set, it is temporarily not considered as a
neighbor, and thus:
o Every RREQ received from this neighbor LOADng Router interface
MUST be discarded;
11. Common Rules for RREQ and RREP Messages
RREQ and RREP messages, both, supply routes between their recipients
and the originator of the RREQ or RREP message. The two message
types therefore share common processing rules, and differ only in the
following:
o RREQ messages are multicast or broadcast, intended to be received
by all LOADng Routers in the network, whereas RREP messages are
all unicast, intended to be received only by LOADng Routers on a
specific route towards a specific destination.
o Receipt of an RREQ message by a LOADng router, which has the
RREQ.destination address in its Local Interface Set or Destination
Address Set MUST trigger the procedures for generation of an RREP
message.
o Receipt of an RREP message with RREP.ackrequired set MUST trigger
generation of an RREP_ACK message.
For the purpose of the processing description in this section, the
following additional notation is used:
received-route-metric is a variable, representing the route metric,
as included in the received RREQ or RREP message, see Section 16.
used-metric-type is a variable, representing the type of metric used
for calculating received-route-metric, see Section 16.
previous-hop is the address of the LOADng Router, from which the
RREQ or RREP message was received.
> is the comparison operator for sequence numbers, as specified in
Section 8.
Clausen, et al. Expires July 10, 2016 [Page 25]
Internet-Draft LOADng January 2016
MSG is a shorthand for either an RREQ or RREP message, used for when
accessing message fields in the description of the common RREQ and
RREP message processing in the following subsections.
hop-count is a variable, representing the hop-count, as included in
the received RREQ or RREP message.
hop-limit is a variable, representing the hop-limit, as included in
the received RREQ or RREP message.
link-metric is a variable, representing the link metric between this
LOADng Router and the LOADng Router from which the RREQ or RREP
message was received, as calculated by the receiving LOADng
Router, see Section 16.
route-metric is a variable, representing the route metric, as
included in the received RREQ or RREP message, plus the link-
metric for the link, over which the RREQ or RREP was received,
i.e., the total route cost from the originator to this LOADng
Router.
11.1. Identifying Invalid RREQ or RREP Messages
A received RREQ or RREP message is invalid, and MUST be discarded
without further processing, if any of the following conditions are
true:
o The address length specified by this message (i.e., MSG.addr-
length + 1) differs from the length of the address(es) of this
LOADng Router.
o The address contained in MSG.originator is an address of this
LOADng Router.
o There is a tuple in the Routing Set where:
* R_dest_addr = MSG.originator
* R_seq_num > MSG.seq-num
o For RREQ messages only, an RREQ MUST be considered invalid if the
previous-hop is blacklisted (i.e., its address is in a tuple in
the Blacklisted Neighbor Set, see Section 10.1).
A LOADng Router MAY recognize additional reasons for identifying that
an RREQ or RREP message is invalid for processing, e.g., to allow a
security mechanism as specified in Section 18.2 to perform
verification of integrity check values and prevent processing of
Clausen, et al. Expires July 10, 2016 [Page 26]
Internet-Draft LOADng January 2016
unverifiable RREQ or RREP message by this protocol.
11.2. RREQ and RREP Message Processing
A received, and valid, RREQ or RREP message is processed as follows:
1. Included TLVs are processed/updated according to their
specification.
2. Set the variable hop-count to MSG.hop-count + 1.
3. Set the variable hop-limit to MSG.hop-limit - 1.
4. If MSG.metric-type is known to this LOADng Router, and if
MSG.metric-type is not HOP_COUNT, then:
* Set the variable used-metric-type to the value of MSG.metric-
type.
* Determine the link metric over the link over which the message
was received, according to used-metric-type, and set the
variable link-metric to the calculated value.
* Compute the route metric to MSG.originator according to used-
metric-type by adding link-metric to the received-route-metric
advertised by the received message, and set the variable
route-metric to the calculated value.
5. Otherwise:
* Set the variable used-metric-type to HOP_COUNT.
* Set the variable route-metric to MAX_DIST, see Section 16.
* Set the variable link-metric to MAX_DIST.
6. Find the Routing Tuple (henceforth, Matching Routing Tuple)
where:
* R_dest_addr = MSG.originator
7. If no Matching Routing Tuple is found, then create a new Matching
Routing Tuple (the "reverse route" for RREQ messages or "forward
route" for RREP messages) with:
* R_dest_addr := MSG.originator
Clausen, et al. Expires July 10, 2016 [Page 27]
Internet-Draft LOADng January 2016
* R_next_addr := previous-hop
* R_metric_type := used-metric-type
* R_metric := MAX_DIST
* R_hop_count := hop-count
* R_seq_num := -1
* R_valid_time := current time + R_HOLD_TIME
* R_bidirectional := FALSE
* R_local_iface_addr := the address of the LOADng Interface
through which the message was received.
8. The Matching Routing Tuple, existing or new, is compared to the
received RREQ or RREP message:
1. If
+ R_seq_num = MSG.seq-num; AND
+ R_metric_type = used-metric-type; AND
+ R_metric > route-metric
OR
+ R_seq_num = MSG.seq-num; AND
+ R_metric_type = used-metric-type; AND
+ R_metric = route-metric; AND
+ R_hop_count > hop-count
OR
+ R_seq_num = MSG.seq-num; AND
+ R_metric_type does not equal to used-metric-type; AND
+ R_metric_type = HOP_COUNT
OR
Clausen, et al. Expires July 10, 2016 [Page 28]
Internet-Draft LOADng January 2016
+ R_seq_num < MSG.seq-num
Then:
1. The message is used for updating the Routing Set. The
Routing Tuple, where:
- R_dest_addr = MSG.originator;
is updated thus:
- R_next_addr := previous-hop
- R_metric_type = used-metric-type
- R_metric := route-metric
- R_hop_count := hop-count
- R_seq_num := MSG.seq-num
- R_valid_time := current time + R_HOLD_TIME
- R_bidirectional := TRUE, if the message being
processed is an RREP.
2. If previous-hop is not equal to MSG.originator, and if
there is no Matching Routing Tuple in the Routing Set
with R_dest_addr = previous-hop, create a new Matching
Routing Tuple with:
- R_dest_addr := previous-hop
- R_next_addr := previous-hop
3. The Routing Tuple with R_dest_addr = previous-hop,
existing or new, is updated as follows
- R_metric_type := used-metric-type
- R_metric := link-metric
- R_hop_count := 1
- R_seq_num := -1
- R_valid_time := current time + R_HOLD_TIME
Clausen, et al. Expires July 10, 2016 [Page 29]
Internet-Draft LOADng January 2016
- R_bidirectional := TRUE, if the processed message is
an RREP, otherwise FALSE.
- R_local_iface_addr := the address of the LOADng
Interface through which the message was received.
2. Otherwise, if the message is an RREQ, it is not processed
further and is not considered for forwarding. If it is an
RREP and if RREP.ackrequired is set, an RREP_ACK message MUST
be sent to the previous-hop, according to Section 15.2. The
RREP is not considered for forwarding.
12. Route Requests (RREQs)
Route Requests (RREQs) are generated by a LOADng Router when it has
data packets to deliver to a destination, where the data packet
source is local to that LOADng Router (i.e., is an address in the
Local Interface Set or Destination Address Set of that LOADng
Router), but for which the LOADng router has no matching tuple in the
Routing Set. Furthermore, if there is a matching tuple in the Routing
Set with the R_bidirectional set to FALSE, and the parameter
USE_BIDIRECTIONAL_LINK_ONLY of the interface with
R_local_iface_address equals TRUE, an RREQ MUST be generated.
After originating an RREQ, a LOADng Router waits for a corresponding
RREP. If no such RREP is received within 2*NET_TRAVERSAL_TIME
milliseconds, the LOADng Router MAY issue a new RREQ for the sought
destination (with an incremented seq_num) up to a maximum of
RREQ_RETRIES times. Two consequent RREQs generated on an interface
of a LOADng Router SHOULD be separated at least RREQ_MIN_INTERVAL.
12.1. RREQ Generation
An RREQ message is generated according to Section 6 with the
following content:
o RREQ.addr-length set to the length of the address, as specified in
Section 6;
o RREQ.metric-type set to the desired metric type;
o RREQ.route-metric := 0.
o RREQ.seq-num set to the next unused sequence number, maintained by
this LOADng Router;
o RREQ.hop-count := 0;
Clausen, et al. Expires July 10, 2016 [Page 30]
Internet-Draft LOADng January 2016
o RREQ.hop-limit := MAX_HOP_LIMIT;
o RREQ.destination := the address to which a route is sought;
o RREQ.originator := one address of the LOADng Interface of the
LOADng Router that generates the RREQ. If the LOADng Router is
generating RREQ on behalf of a host connected to this LOADng
Router, the source address of the data packet, generated by that
host, is used;
12.2. RREQ Processing
The variables hop-count and hop-limit have been updated in
Section 11.2 (when processing the message) and are used in this
section. On receiving an RREQ message, a LOADng Router MUST process
the message according to this section:
1. If the message is invalid for processing, as defined in
Section 11.1, the message MUST be discarded without further
processing. The message is not considered for forwarding.
2. Otherwise, the message is processed according to Section 11.2.
3. If RREQ.destination is listed in I_local_iface_addr_list of any
Local Interface Tuple, or corresponds to D_address of any
Destination Address Tuple of this LOADng Router, the RREP
generation process in Section 13.1 MUST be applied. The RREQ is
not considered for forwarding.
4. Otherwise, if hop-count is less than MAX_HOP_COUNT and hop-limit
is greater than 0, the message is considered for forwarding
according to Section 12.3.
12.3. RREQ Forwarding
The variables used-metric type, hop-count, hop-limit and route-metric
have been updated in Section 11.2 (when processing the message) and
are used in this section to update the content of the message to be
forwarded. An RREQ, considered for forwarding, MUST be updated as
follows, prior to it being transmitted:
1. RREQ.metric-type := used-metric-type (as set in Section 11.2)
2. RREQ.route-metric := route-metric (as set in Section 11.2)
3. RREQ.hop-count := hop-count (as set in Section 11.2)
Clausen, et al. Expires July 10, 2016 [Page 31]
Internet-Draft LOADng January 2016
4. RREQ.hop-limit := hop-limit (as set in Section 11.2)
An RREQ MUST be forwarded according to the flooding operation,
specified for the network. This MAY be by way of classic flooding, a
reduced relay set mechanism such as [RFC6621], or any other
information diffusion mechanism such as [RFC6206]. Care must be
taken that NET_TRAVERSAL_TIME is chosen so as to accommodate for the
maximum time that may take for an RREQ to traverse the network,
accounting for in-router delays incurring due to or imposed by such
algorithms.
12.4. RREQ Transmission
RREQs, whether initially generated or forwarded, are sent to all
neighbor LOADng Routers through all interfaces in the Local Interface
Set.
When an RREQ is transmitted, all receiving LOADng Routers will
process the RREQ message and as a consequence consider the RREQ
message for forwarding at the same, or at almost the same, time. If
using data link and physical layers that are subject to packet loss
due to collisions, such RREQ messages SHOULD be jittered as described
in [RFC5148], using RREQ_MAX_JITTER, in order to avoid such losses.
13. Route Replies (RREPs)
Route Replies (RREPs) are generated by a LOADng Router in response to
an RREQ (henceforth denoted "corresponding RREQ"), and are sent by
the LOADng Router which has, in either its Destination Address Set or
in its Local Interface Set, the address from RREQ.destination. RREPs
are sent, hop by hop, in unicast towards the originator of the RREQ,
in response to which the RREP was generated, along the Reverse Route
installed by that RREQ. A LOADng Router, upon forwarding an RREP,
installs the Forward Route towards the RREP.destination.
Thus, with forwarding of RREQs installing the Reverse Route and
forwarding of RREPs installing the Forward Route, bi-directional
routes are provided between the RREQ.originator and RREQ.destination.
13.1. RREP Generation
At least one RREP MUST be generated in response to a (set of)
received RREQ messages with identical (RREQ.originator, RREQ.seq-
num). An RREP MAY be generated immediately as a response to each
RREQ processed, in order to provide shortest possible route
establishment delays, or MAY be generated after a certain delay after
the arrival of the first RREQ, in order to use the "best" received
RREQ (e.g., received over the lowest-cost route) but at the expense
Clausen, et al. Expires July 10, 2016 [Page 32]
Internet-Draft LOADng January 2016
of longer route establishment delays. A LOADng Router MAY generate
further RREPs for subsequent RREQs received with the same
(RREQ.originator, RREQ.seq-num) pairs, if these indicate a better
route, at the expense of additional control traffic being generated.
In all cases, however, the content of an RREP is as follows:
o RREP.addr-length set to the length of the address, as specified in
Section 6;
o RREP.seq-num set to the next unused sequence number, maintained by
this LOADng Router;
o RREP.metric-type set to the same value as the RREQ.metric-type in
the corresponding RREQ if the metric type is known to the router.
Otherwise, RREP.metric-type is set to HOP_COUNT;
o RREP.route-metric := 0
o RREP.hop-count := 0;
o RREP.hop-limit := MAX_HOP_LIMIT;
o RREP.destination := the address to which this RREP message is to
be sent; this corresponds to the RREQ.originator from the RREQ
message, in response to which this RREP message is generated;
o RREP.originator := the address of the LOADng Router, generating
the RREP. If the LOADng Router is generating an RREP on behalf of
the hosts connected to it, or on behalf of one of the addresses
contained in the LOADng Routers Destination Address Set, the host
address is used.
The RREP that is generated is transmitted according to Section 13.4.
13.2. RREP Processing
The variables hop-count and hop-limit have been updated in
Section 11.2 (when processing the message) and are used in this
section. On receiving an RREP message, a LOADng Router MUST process
the message according to this section:
1. If the message is invalid for processing, as defined in
Section 11.1, the message MUST be discarded without further
processing. The message is not considered for forwarding.
2. Otherwise, the message is processed according to Section 11.2.
Clausen, et al. Expires July 10, 2016 [Page 33]
Internet-Draft LOADng January 2016
3. If RREP.ackrequired is set, an RREP_ACK message MUST be sent to
the previous-hop, according to Section 15.2.
4. If hop-count is equal to MAX_HOP_COUNT or hop-limit is equal to
0, the message is not considered for forwarding.
5. Otherwise, if RREP.destination is not listed in
I_local_iface_addr_list of any Local Interface Tuple and does not
correspond to D_address of any Destination Address Tuple of this
LOADng Router, the RREP message is considered for forwarding
according to Section 13.3.
13.3. RREP Forwarding
The variables used-metric type, hop-count, hop-limit and route-metric
have been updated in Section 11.2 (when processing the message) and
are used in this section to update the content of the message to be
forwarded. An RREP message, considered for forwarding, MUST be
updated as follows, prior to it being transmitted:
1. RREP.metric-type := used-metric-type (as set in Section 11.2)
2. RREP.route-metric := route-metric (as set in Section 11.2)
3. RREP.hop-count := hop-count (as set in Section 11.2)
4. RREP.hop-limit := hop-limit (as set in Section 11.2)
5. The RREP is transmitted, according to Section 13.4.
The RREP message is then unicast to the next hop towards
RREP.destination.
13.4. RREP Transmission
An RREP is, ultimately, destined for the LOADng Router which has the
address listed in the RREP.destination field in either of its Local
Interface Set, or in its Destination Address Set. The RREP is
forwarded in unicast towards that LOADng Router. The RREP MUST,
however, be transmitted so as to allow it to be processed in each
intermediate LOADng Router to:
o Install proper forward routes; AND
o Permit that RREP.hop-count be updated to reflect the route.
RREP Transmission is accomplished by the following procedure:
Clausen, et al. Expires July 10, 2016 [Page 34]
Internet-Draft LOADng January 2016
1. Find the Routing Tuple (henceforth, the "Matching Routing Tuple")
in the Routing Set, where:
* R_dest_addr = RREP.destination
2. Find the Local Interface Tuple (henceforth, "Matching Interface
Tuple), where:
* I_local_iface_addr_list contains R_local_iface_addr from the
Matching Routing Tuple
3. If RREP_ACK_REQUIRED is set for the LOADng Interface, identified
by the Matching Interface Tuple:
* Create a new Pending Acknowledgment Tuple with:
+ P_next_hop := R_next_addr from the Matching Routing Tuple
+ P_originator := RREP.originator
+ P_seq_num := RREP.seq-num
+ P_ack_received := FALSE
+ P_ack_timeout := current_time + RREP_ACK_TIMEOUT
* RREP.ackrequired := TRUE
4. Otherwise:
* RREP.ackrequired := FALSE
5. The RREP is transmitted over the LOADng Interface, identified by
the Matching Interface Tuple to the neighbor LOADng Router,
identified by R_next_addr from the Matching Routing Tuple.
When a Pending Acknowledgement Tuple expires, if P_ack_received =
FALSE, the P_next_hop address MUST be blacklisted by creating a
Blacklisted Neighbor Tuple according to Section 7.3
14. Route Errors (RERRs)
If a LOADng Router fails to deliver a data packet to a next hop or a
destination, and if neither the source nor destination address of
that data packet belongs to the Destination Address Set of that
LOADng Router, it MUST generate a Route Error (RERR). This RERR MUST
be sent along the Reverse Route towards the source of the data packet
for which delivery was unsuccessful (to the last LOADng Router along
Clausen, et al. Expires July 10, 2016 [Page 35]
Internet-Draft LOADng January 2016
the Reverse Route, if the data packet was originated by a host behind
that LOADng Router).
The following definition is used in this section:
o "EXPIRED" indicates that a timer is set to a value clearly
preceding the current time (e.g., current time - 1).
14.1. Identifying Invalid RERR Messages
A received RERR is invalid, and MUST be discarded without further
processing, if any of the following conditions are true:
o The address length specified by this message (i.e., RERR.addr-
length + 1) differs from the length of the address(es) of this
LOADng Router.
o The address contained in RERR.originator is an address of this
LOADng Router.
A LOADng Router MAY recognize additional reasons, external to this
specification, for identifying that an RERR message is invalid for
processing, e.g., to allow a security mechanism as specified in
Section 18.2 to perform verification of integrity check values and
prevent processing of unverifiable RERR message by this protocol.
14.2. RERR Generation
A packet with an RERR message is generated by the LOADng Router,
detecting the link breakage, with the following content:
o RERR.error-code := the error code corresponding to the event
causing the RERR to be generated, from among those recorded in
Table 1;
o RERR.addr-length := the length of the address, as specified in
Section 6;
o RERR.unreachableAddress := the destination address from the
unsuccessfully delivered data packet.
o RERR.originator := one address of the LOADng Interface of the
LOADng Router that generates the RERR.
o RERR.destination := the source address from the unsuccessfully
delivered data packet, towards which the RERR is to be sent.
Clausen, et al. Expires July 10, 2016 [Page 36]
Internet-Draft LOADng January 2016
o RERR.hop-limit := MAX_HOP_LIMIT;
14.3. RERR Processing
For the purpose of the processing description below, the following
additional notation is used:
previous-hop is the address of the LOADng Router, from which the
RERR was received.
hop-limit is a variable, representing the hop-limit, as included in
the received RERR message.
Upon receiving an RERR, a LOADng Router MUST perform the following
steps:
1. If the RERR is invalid for processing, as defined in
Section 14.1, the RERR MUST be discarded without further
processing. The message is not considered for forwarding.
2. Included TLVs are processed/updated according to their
specification.
3. Set the variable hop-limit to RERR.hop-limit - 1.
4. Find the Routing Tuple (henceforth "matching Routing Tuple") in
the Routing Set where:
* R_dest_addr = RERR.unreachableAddress
* R_next_addr = previous-hop
5. If no matching Routing Tuple is found, the RERR is not processed
further, but is considered for forwarding, as specified in
Section 14.4.
6. Otherwise, if one matching Routing Tuple is found:
1. If RERR.errorcode is 0 ("No available route", as specified in
Section 19.1), this matching Routing Tuple is updated as
follows:
+ R_valid_time := EXPIRED
Extensions to this specification MAY define additional error
codes in the Error Code IANA registry, and MAY insert
processing rules here for RERRs with that error code.
Clausen, et al. Expires July 10, 2016 [Page 37]
Internet-Draft LOADng January 2016
2. If hop-limit is greater than 0, the RERR message is
considered for forwarding, as specified in Section 14.4
14.4. RERR Forwarding
An RERR is, ultimately, destined for the LOADng Router which has, in
either its Destination Address Set or in its Local Interface Set, the
address from RERR.originator.
An RERR, considered for forwarding is therefore processed as follows:
1. RERR.hop-limit := hop-limit (as set in Section 14.3)
2. Find the Destination Address Tuple (henceforth, matching
Destination Address Tuple) in the Destination Address Set where:
* D_address = RERR.destination
3. If one or more matching Destination Address Tuples are found, the
RERR message is discarded and not retransmitted, as it has
reached the final destination.
4. Otherwise, find the Local Interface Tuple (henceforth, matching
Local Interface Tuple) in the Local Interface Set where:
* I_local_iface_addr_list contains RERR.destination.
5. If a matching Local Interface Tuple is found, the RERR message is
discarded and not retransmitted, as it has reached the final
destination.
6. Otherwise, if no matching Destination Address Tuples or Local
Interface Tuples are found, the RERR message is transmitted
according to Section 14.5.
14.5. RERR Transmission
An RERR is, ultimately, destined for the LOADng Router which has the
address listed in the RERR.destination field in either of its Local
Interface Set, or in its Destination Address Set. The RERR is
forwarded in unicast towards that LOADng Router. The RERR MUST,
however, be transmitted so as to allow it to be processed in each
intermediate LOADng Router to:
o Allow intermediate LOADng Routers to update their Routing Sets,
i.e., remove tuples for this destination.
RERR Transmission is accomplished by the following procedure:
Clausen, et al. Expires July 10, 2016 [Page 38]
Internet-Draft LOADng January 2016
1. Find the Routing Tuple (henceforth, the "Matching Routing Tuple")
in the Routing Set, where:
* R_dest_addr = RERR.destination
2. Find the Local Interface Tuple (henceforth, "Matching Interface
Tuple), where:
* I_local_iface_addr_list contains R_local_iface_addr from the
Matching Routing Tuple
3. The RERR is transmitted over the LOADng Interface, identified by
the Matching Interface Tuple to the neighbor LOADng Router,
identified by R_next_addr from the Matching Routing Tuple.
15. Route Reply Acknowledgments (RREP_ACKs)
A LOADng Router MUST signal in a transmitted RREP that it is
expecting an RREP_ACK, by setting RREP.ackrequired flag in the RREP.
When doing so, the LOADng Router MUST also add a tuple (P_next_hop,
P_originator, P_seq_num, P_ack_timeout) to the Pending Acknowledgment
Set, and set P_ack_timeout to current_time + RREP_ACK_TIMEOUT, as
described in Section 13.4.
The following definition is used in this section:
o "EXPIRED" indicates that a timer is set to a value clearly
preceding the current time (e.g., current_time - 1).
15.1. Identifying Invalid RREP_ACK Messages
A received RREP_ACK is invalid, and MUST be discarded without further
processing, if any of the following conditions are true:
o The address length specified by this message (i.e., RREP_ACK.addr-
length + 1) differs from the length of the address(es) of this
LOADng Router.
A LOADng Router MAY recognize additional reasons, external to this
specification, for identifying that an RREP_ACK message is invalid
for processing, e.g., to allow a security protocol to perform
verification of signatures and prevent processing of unverifiable
RREP_ACK message by this protocol.
15.2. RREP_ACK Generation
Upon reception of an RREP message with the RREP.ackrequired flag set,
a LOADng Router MUST generate at least one RREP_ACK and send this
Clausen, et al. Expires July 10, 2016 [Page 39]
Internet-Draft LOADng January 2016
RREP_ACK in unicast to the neighbor which originated the RREP.
An RREP_ACK message is generated by a LOADng Router with the
following content:
o RREP_ACK.addr-length := the length of the address, as specified in
Section 6;
o RREP_ACK.seq-num := the value of the RREP.seq-num field of the
received RREP;
o RREP_ACK.destination := RREP.originator of the received RREP.
15.3. RREP_ACK Processing
On receiving an RREP_ACK from a LOADng neighbor LOADng Router, a
LOADng Router MUST do the following:
1. If the RREP_ACK is invalid for processing, as defined in
Section 15.1, the RREP_ACK MUST be discarded without further
processing.
2. Find the Routing Tuple (henceforth, Matching Routing Tuple)
where:
* R_dest_addr = previous-hop;
The Matching Routing Tuple is updated as follows:
* R_bidirectional := TRUE
3. If a Pending Acknowledgement Tuple (henceforth, Matching Pending
Acknowledgement Tuple) exists, where:
* P_next_hop is the address of the LOADng Router from which the
RREP_ACK was received.
* P_originator = RREP_ACK.destination
* P_seq_num = RREP_ACK.seq-num
Then the RREP has been acknowledged. The Matching Pending
Acknowledgement Tuple is updated as follows:
* P_ack_received := TRUE
* P_ack_timeout := EXPIRED
Clausen, et al. Expires July 10, 2016 [Page 40]
Internet-Draft LOADng January 2016
15.4. RREP_ACK Forwarding
An RREP_ACK is intended only for a specific direct neighbor, and MUST
NOT be forwarded.
15.5. RREP_ACK Transmission
An RREP_ACK is transmitted, in unicast, to the neighbor LOADng Router
from which the RREP was received.
16. Metrics
This specification enables the use of different metrics for when
calculating route metrics.
Metrics as defined in LOADng are additive, and the routes that are to
be created are those with the minimum sum of the metrics along that
route.
16.1. Specifying New Metrics
When defining a metric, the following considerations SHOULD be taken
into consideration:
o The definition of the R_metric field, as well as the value of
MAX_DIST.
17. Implementation Status
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and based on a proposal described in [RFC6982]. The
description of implementations in this section is intended to assist
the IETF in its decision processes in progressing drafts to RFCs.
Please note that the listing of any individual implementation here
does not imply endorsement by the IETF. Furthermore, no effort has
been spent to verify the information presented here that was supplied
by IETF contributors. This is not intended as, and must not be
construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to [RFC6982], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
Clausen, et al. Expires July 10, 2016 [Page 41]
Internet-Draft LOADng January 2016
In the following subsections, each publicly-known implementation of
LOADng is listed. There are currently four publicly-known
implementations of LOADng. These have been tested for
interoperability in at least three interop events, as described in
[I-D.loadng-interop-report].
17.1. Implementation of Ecole Polytechnique
This implementation is developed by the Networking Group at Ecole
Polytechnique. It can run over real network interfaces, and can also
be integrated with the network simulator NS2. It is a Java
implementation, and can be used on any platform that includes a Java
virtual machine.
The implementation has been maintained since the 00 revision of
LOADng, and is quite mature. It has been tested in interoperability
events with other implementations (as described in
[I-D.loadng-interop-report]), and in large-scale network simulations
with up to 1000 routers. There have been several scientific
publications based on this implementation, such as [IEEE_VTC2012]
[IEEE_WiCom2012] [IEEE_ICWITS2012].
All the protocol functions of this revision (-08) of the
specification, including RREQ/RREP/RREP-ACK/RERR generation,
processing, forwarding and transmission, as well as blacklisting, are
implemented.
The latest implementation conforms to the LOADng-07 revision as
documented in this specification. This software is currently closed
source.
17.2. Implementation of Fujitsu Laboratories of America
This implementation is developed by Fujitsu Laboratories of America.
It is a Java implementation, structured in multiple separate modules,
notably a [RFC5444] generator and parser, and integration module in
the network simulator Ns-2, a kernel module for integrating the
implementation in a Linux kernel (not yet completed), and the
protocol core.
The implementation is mature and has been tested both in
interoperability tests with other implementations
[I-D.loadng-interop-report], as well as large-scale simulations with
hundreds of routers. The implementation is not currently used in
deployments. The implementation supports all LOADng functions (RREQ,
RREP, RREP-ACK generation, processing, forwarding and transmission),
and conforms to the LOADng-06 specification. The software is
currently closed source.
Clausen, et al. Expires July 10, 2016 [Page 42]
Internet-Draft LOADng January 2016
17.3. Implementation of Hitachi Yokohama Research Laboratory - 1
This implementation is developed by Hitachi, Ltd. Yokohama Research
Laboratory. It can run over real embedded devices. It is a C
implementation. The implementation is maintained since the 00
revision of LOADng. It was tested in the first interoperability
event with other implementations, as described in
[I-D.loadng-interop-report].
This implementation is alpha version, mainly for performance test and
evaluations. All the functions of the protocol, including RREQ/RREP/
RREP-ACK/RERR generation, processing, forwarding and transmission,
blacklisting, have been implemented. Also a RFC5444 generator and
parser have been implemented. The latest implementation conforms to
LOADng-06 revision. This software is currently closed source.
17.4. Implementation of Hitachi Yokohama Research Laboratory -2
This implementation is developed by Hitachi, Ltd. Yokohama Research
Laboratory. It can run over real network interface, and can also be
integrated with network simulator NS2. It is a C++ implementation.
The implementation is mature and maintained since the 00 revision of
LOADng. It was tested in large-scale network simulations up to 500
routers.
All the functions of the protocol, including RREQ/RREP/RREP-ACK/RERR
generation, processing, forwarding and transmission, blacklisting,
have been implemented. The latest implementation conforms to the
LOADng-05 revision. This software is currently closed source.
18. Security Considerations
This section analyzes security threats of LOADng, and specifies
mandatory-to-implement security mechanisms of LOADng for integrity
and replay projection. A deployment of LOADng protocol may choose to
employ an alternative(s) to these mechanisms. For example, it may
choose to use an alternative Integrity Check Value (ICV) with
preferred properties, and/or it may use an alternative timestamp. A
deployment may choose to use no such security mechanisms, but this is
not recommended.
Section 18.1 illustrates the security threats of the protocol
assuming if no security measure is applied. Section 18.2 specifies
how to use Integrity Check Value (ICV) and timestamps to project the
protocol messages, and how the security mechanisms can alleviate the
threats.
Clausen, et al. Expires July 10, 2016 [Page 43]
Internet-Draft LOADng January 2016
18.1. Security Threats
As a reactive routing protocol, this protocol is a potential target
for various attacks. Various possible vulnerabilities are discussed
in this section. For each kind of threats, the vulnerabilities of
the protocol is firstly analyzed, with the assumption that no
security measure is applied. Then how the integrity protection
specified in Section 18.2 can alleviate the threats are discussed,
with the analyses of limitations.
18.1.1. Confidentiality
This protocol floods Route Requests (RREQs) to all the LOADng Routers
in the network, when there is traffic to deliver to a given
destination. Hence, if used in an unprotected network (such as an
unprotected wireless network):
o Part of the network topology is revealed to anyone who listens,
specifically (i) the identity (and existence) of the source LOADng
Router; (ii) the identity of the destination; and (iii) the fact
that a path exists between the source LOADng Router and the LOADng
Router from which the RREQ was received.
o The network traffic patterns are revealed to anyone who listens to
the LOADng control traffic, specifically which pairs of devices
communicate. If, for example, a majority of traffic originates
from or terminates in a specific LOADng Router, this may indicate
that this LOADng Router has a central role in the network.
This protocol also unicasts Route Replies (RREPs) from the
destination of an RREQ to the originator of that same RREQ. Hence,
if used in an unprotected network (such as an unprotected wireless
network):
o Part of the network topology is revealed to anyone who is near or
on the unicast path of the RREP (such as within radio range of
LOADng Routers on the unicast path in an unprotected wireless
network), specifically that a path from the originator (of the
RREP) to the destination (of the RREP) exists.
Finally, this protocol unicasts Route Errors (RERRs) when an
intermediate LOADng Router detects that the path from a source to a
destination is no longer available. Hence, if used in an unprotected
network (such as an unprotected wireless network):
o A disruption of the network topology is revealed to anyone who is
near or on the unicast path of the RERR (such as within radio
range of LOADng Routers on the unicast path in an unprotected
Clausen, et al. Expires July 10, 2016 [Page 44]
Internet-Draft LOADng January 2016
wireless network), specifically that a path from the originator
(of the RERR) to the destination (of the RERR) has been disrupted.
This protocol signaling behavior enables, for example, an attacker to
identify central devices in the network (by monitoring RREQs) so as
to target an attack, and (by way of monitoring RERRs) to measure the
success of an attack.
This protocol does not specify mechanism to protect the
confidentiality of network topology. Unless the information about
the network topology itself is confidential, integrity of control
messages is sufficient to admit only trusted routers (i.e., routers
with valid credentials) to the network.
In situations where the confidentiality of the network topology is of
importance, regular cryptographic techniques, can be applied to
ensure that control traffic can be read and interpreted by only those
authorized to do so.
18.1.2. Integrity
A LOADng Router injects topological information into the network by
way of transmitting RREQ and RREP messages, and removes installed
topological information by way of transmitting RERR messages. If
some LOADng Routers for some reason, malice or malfunction, are able
to inject invalid control traffic, network integrity may be
compromised. Therefore, message authentication is recommended.
Different such situations may occur if not integrity protection
mechanism is applied, for instance:
1. A LOADng Router generates RREQ messages, pretending to be another
LOADng Router;
2. A LOADng Router generates RREP messages, pretending to be another
LOADng Router;
3. A LOADng Router generates RERR messages, pretending to be another
LOADng Router;
4. A LOADng Router generates RERR messages, indicating that a link
on a path to a destination is broken;
5. A LOADng Router forwards altered control messages;
6. A LOADng Router does not forward control messages;
Clausen, et al. Expires July 10, 2016 [Page 45]
Internet-Draft LOADng January 2016
7. A LOADng Router forwards RREPs and RREQs, but does not forward
unicast data traffic;
8. A LOADng Router "replays" previously recorded control messages
from another LOADng Router.
18.1.3. Channel Jamming and State Explosion
A reactive protocol, LOADng control messages are generated in
response to network events. For RREQs, such an event is that a data
packet is present in a router which does not have a route to the
destination of the data packet, or that the router receives an RERR
message, invalidating a route. For RREPs, such an event is the
receipt of an RREQ corresponding to a destination owned by the LOADng
Router. A router that forwards an RREQ records the reverse route
state. A router that forwards an RREP records the forward route
state. If some routers for some reason, malice or malfunction,
generates excessive RREQ, RREP or RERRs, otherwise correctly
functioning LOADng Routers may fall victim to either "indirect
jamming" (being "tricked" into generating excessive control traffic)
or an explosion in the state necessary for maintaining protocol state
(potentially, exhausting the available memory resources).
Different such situations may occur, for instance:
1. A router, within a short time, generates RREQs to an excessive
amount of destinations in the network (possibly all destinations,
possibly even destinations not present in the network), causing
intermediate routers to allocate state for the forward routes.
2. A router generates excessively frequent RREQs to the same
(existing) destination, causing the corresponding LOADng Router
to generate excessive RREPs.
3. A router generates RERRs for a destination to the source LOADng
Router for traffic to that destination, causing that LOADng
Router to flood renewed RREQs.
For situation 1, the state required for recording forward and/or
reverse routes may exceed the memory available in the intermediate
LOADng Routers - to the detriment of being able of recording state
for other routes. This, in particular, if a LOADng Router generates
RREQs for destinations "not present in the network".
A router which, within a short time, generates RREPs to an excessive
amount of destinations in the network (possibly all destinations,
possibly even destinations not present in the network), will not have
the same network-wide effect: an intermediate router receiving an
Clausen, et al. Expires July 10, 2016 [Page 46]
Internet-Draft LOADng January 2016
RREP for a destination for which no reverse route exists will neither
attempt forwarding the RREP nor allocate state for the forward route.
For situations 1, 2, and 3, a possible countermeasure is to rate-
limit the number of control messages that a LOADng Router forwards on
behalf of another LOADng Router. Such a rate limit should take into
consideration the expected normal traffic for a given LOADng
deployment. Authentication may furthermore be used so as to prohibit
a LOADng Router from forwarding control traffic from any non-
authenticated router (with the assumption being that an authenticated
router is not expected to exhibit such rogue behavior).
18.1.4. Interaction with External Routing Domains
This protocol does provide a basic mechanism for a LOADng Router to
be able to discover routes to external routing domains: a LOADng
Router configured to "own" a given set of addresses will respond to
RREQs for destinations with these addresses, and can - by whatever
protocols governing the routing domain wherein these addresses exist
- provide paths to these addresses.
When operating routers connecting a LOADng domain to an external
routing domain, destinations inside the LOADng domain can be injected
into the external domain, if the routing protocol governing that
domain so permits. Care MUST be taken to not allow potentially
insecure and untrustworthy information to be injected into the
external domain.
In case LOADng is used on the IP layer, a RECOMMENDED way of
extending connectivity from an external routing domain to a LOADng
routed domain is to assign an IP prefix (under the authority of the
routers/gateways connecting the LOADng routing domain with the
external routing domain) exclusively to that LOADng routing domain,
and to statically configure gateways to advertise routes for that
prefix into the external domain. Within the LOADng domain, gateways
SHOULD only generate RREPs for destinations which are not part of
that prefix; this is in particularly important if a gateway otherwise
provides connectivity to "a default route".
18.2. Integrity Protection
The mechanisms specified are the use of an ICV for protection of the
protocols' control messages and the use of timestamps in those
messages to prevent replay attacks. Both use the TLV mechanism
specified in [RFC5444] to add this information to the messages.
These ICV and TIMESTAMP TLVs are defined in [RFC7182].
Clausen, et al. Expires July 10, 2016 [Page 47]
Internet-Draft LOADng January 2016
18.2.1. Overview
When an RREQ/RREP/RREP_ACK/RERR message is being processed, LOADng
specifies that it MAY recognize additional reasons for identifying
invalid messages (Section 11.1 and Section 14.1 ). This section
specifies a mechanism that provides this functionality.
Implementations of this protocol MUST include this mechanism, and
deployments of LOADng SHOULD use this mechanism, except when a
different security mechanism is more appropriate.
The integrity protection mechanism specified in this section is
placed in the control packet/message processing flow as indicated in
Figure 1. It exists between the control packet parsing/generation
function of [RFC5444] and the message processing/generation function
of LOADng.
| |
Incoming | /|\ Outgoing
packet \|/ | packet
| |
+--------------------------------+
| |
| RFC 5444 packet |
| parsing/generation |
| |
+--------------------------------+
| |
Messages | /|\ Messages with
\|/ | added TLVs
| |
D +--------------------------------+
R /__________________ | |
O \ Messages | Integrity protection specified |
P (failed check) | in this section |
| |
+--------------------------------+
| |
Messages | /|\ Messages
(passed check) \|/ |
| |
+--------------------------------+
| |
| LOADng message |
| processing/generation |
| |
+--------------------------------+
Figure 1: Relationship with RFC5444 and LOADng
Clausen, et al. Expires July 10, 2016 [Page 48]
Internet-Draft LOADng January 2016
The integrity projection mechanism:
o Specifies an association of ICVs with protocol messages, and
specifies how to use a missing or invalid ICV as a reason to
reject a message as invalid for processing.
o Specifies the implementation of an ICV Message TLV, defined in
[RFC7182], using a SHA-256-based Hashed Message Authentication
Code (HMAC) applied to the appropriate message contents.
Implementations of this protocol MUST support an HMAC-SHA-256 ICV
TLV, and deployments SHOULD use it except when use of a different
algorithm is more appropriate. An implementation MAY use more
than one ICV TLV in a message, as long as they each use a
different algorithm or key to calculate the ICV.
o Specifies the implementation of a TIMESTAMP Message TLV, defined
in [RFC7182], to provide message replay protection.
Implementations of LOADng using this mechanism MUST support a
timestamp based on POSIX time, and deployments SHOULD use it if
the clocks in all routers in the network can be synchronized with
sufficient precision.
o Assumes that a router that is able to generate correct integrity
check values is considered trusted.
This mechanism does not:
o Specify which key identifiers are to be used in a MANET in which
the routers share more than one secret key. (Such keys will be
differentiated using the <key-id> field defined in an ICV TLV
in [RFC7182].)
o Specify how to distribute cryptographic material (shared secret
key(s)).
o Specify how to detect compromised routers with valid keys.
o Specify how to handle (revoke) compromised routers with valid
keys.
No key management mechanism is specified in this scenario because
given the various application scenarios of LOADng, it is hard to
identify a basic mechanism that fits for all. Depending on the
applications, either automated key management or manual key
management [RFC4107] can be used. For example, in a controlled
industrial environments but with very limited data rate and high
delay, a manual key management is probably preferred. In a home
applications, simple pairing mechanisms for key exchange can be
Clausen, et al. Expires July 10, 2016 [Page 49]
Internet-Draft LOADng January 2016
applied. However, in a malicious environments, such as battlefield,
a much more sophisticated key management is desired, by taking
consideration of compromised routers, etc.
18.2.2. Message Generation and Processing
18.2.2.1. Message Content
Messages MUST have the content specified in Section 6. In addition,
messages that conform to the integration protection mechanism MUST
contain:
o At least one ICV Message TLV (as specified in [RFC7182]),
generated according to Section 18.2.2.2. Implementations of
LOADng MUST support the following version of the ICV TLV, but
other versions MAY be used instead, or in addition, in a
deployment, if more appropriate:
* For RREQ/RREP/RREP_ACK/RERR messages, type-extension := 1
* hash-function := 3 (SHA-256)
* cryptographic-function := 3 (HMAC)
o At least one TIMESTAMP Message TLV (as specified in [RFC7182]),
generated according to Section 18.2.2.2. Implementations of
LOADng using this mechanism MUST support the following version of
the TIMESTAMP TLV, but other versions MAY be used instead, or in
addition, in a deployment, if more appropriate:
* type-extension := 1
18.2.2.2. Message Generation
For each RREQ/RREP/RREP_ACK/RERR message, after message generation
and before message transmission, the additional TLVs specified in
Section 18.2.2.1 MUST (unless already present) be added to the
outgoing message when using this mechanism.
The following processing steps (when using a single timestamp version
and a single ICV algorithm) MUST be performed for a cryptographic
algorithm that is used for generating an ICV for a message:
1. All ICV TLVs (if any) are temporarily removed from the message.
Any temporarily removed ICV TLVs MUST be stored, in order to be
reinserted into the message in step 5. The message size and
Message TLV Block size are updated accordingly.
Clausen, et al. Expires July 10, 2016 [Page 50]
Internet-Draft LOADng January 2016
2. All the mutable fields of the message (specified in Section 6)
are temporarily set to 0.
3. A TLV of type TIMESTAMP, as specified in Section 18.2.2.1, is
added to the Message TLV Block. The message size and Message TLV
Block size are updated accordingly.
4. A TLV of type ICV, as specified in Section 18.2.2.1, is added to
the Message TLV Block. The message size and Message TLV Block
size are updated accordingly.
5. All ICV TLVs that were temporary removed in step 1, are restored.
The message size and Message TLV Block size are updated
accordingly.
6. All mutable fields that are temporarily set to 0 are restored to
their previous values.
An implementation MAY add either alternative TIMESTAMP and/or ICV
TLVs or more than one TIMESTAMP and/or ICV TLVs. All TIMESTAMP TLVs
MUST be inserted before adding ICV TLVs.
18.2.2.3. Message Processing
LOADng gives a number of conditions that will lead to a rejection of
the message as "invalid". When using a single timestamp version, and
a single ICV algorithm, add the following conditions to that list,
each of which, if true, MUST cause LOADng to consider the message as
invalid for processing when using this integrity protection
mechanism:
1. The Message TLV Block of the message does not contain exactly one
TIMESTAMP TLV of the selected version. This version
specification includes the type extension. (The Message TLV
Block may also contain TIMESTAMP TLVs of other versions.)
2. The Message TLV Block does not contain exactly one ICV TLV using
the selected algorithm and key identifier. This algorithm
specification includes the type extension, and for type
extensions 1, the hash function and cryptographic function. (The
Message TLV Block may also contain ICV TLVs using other
algorithms and key identifiers.)
3. Validation of the identified (in step 1) TIMESTAMP TLV in the
Message TLV Block of the message fails, as according to the
timestamp validation:
Clausen, et al. Expires July 10, 2016 [Page 51]
Internet-Draft LOADng January 2016
1. If the current POSIX time minus the value of that TIMESTAMP
TLV is greater than NET_TRAVERSAL_TIME, then the message
validation fails.
2. Otherwise, the message validation succeeds.
4. Validation of the identified (in step 2) ICV TLV in the Message
TLV Block of the message fails, as according to the ICV
validation:
1. All ICV Message TLVs (including the identified ICV Message
TLV) are temporarily removed from the message, and the
message size and Message TLV Block size are updated
accordingly.
2. All the mutable fields of the message (specified in
Section 6) are temporarily set to 0.
3. Calculate the ICV for the parameters specified in the
identified ICV Message TLV, as specified in [RFC7182].
4. If this ICV differs from the value of <ICV-data> in the
ICV Message TLV, then the message validation fails. If the
<ICV-data> has been truncated (as specified in [RFC7182],
the ICV calculated in the previous step MUST be truncated to
the TLV length of the ICV Message TLV before comparing it
with the <ICV-data>.
5. Otherwise, the message validation succeeds. The message's
mutable fields are restored to their previous value, and the
ICV Message TLVs are returned to the message, whose size is
updated accordingly.
19. LOADng Specific IANA Considerations
19.1. Error Codes
IANA is requested to create a new registry for Error Codes, with
initial assignments and allocation policies as specified in Table 1.
+---------+--------------------+-------------------+
| Code | Description | Allocation Policy |
+---------+--------------------+-------------------+
| 0 | No available route | |
| 1-251 | Unassigned | Expert Review |
| 252-255 | Unassigned | Experimental Use |
+---------+--------------------+-------------------+
Clausen, et al. Expires July 10, 2016 [Page 52]
Internet-Draft LOADng January 2016
Table 1: Error Codes
20. Contributors
This specification is the result of the joint efforts of the
following contributors - listed alphabetically.
o Alberto Camacho, LIX, France, <alberto@albertocamacho.com>
o Thomas Heide Clausen, LIX, France, <T.Clausen@computer.org>
o Axel Colin de Verdiere, LIX, France, <axel@axelcdv.com>
o Kenneth Garey, Maxim Integrated Products, USA,
<kenneth.garey@maxim-ic.com>
o Ulrich Herberg, Fujitsu Laboratories of America, USA
<ulrich.herberg@us.fujitsu.com>
o Yuichi Igarashi, Hitachi Ltd, Yokohama Research Laboratory, Japan,
<yuichi.igarashi.hb@hitachi.com>
o Cedric Lavenu, EDF R&D, France, <cedric-2.lavenu@edf.fr>
o Afshin Niktash, Maxim Integrated Products, USA,
<afshin.niktash@maxim-ic.com>
o Charles E. Perkins, Futurewei Inc, USA, <charliep@computer.org>
o Hiroki Satoh, Hitachi Ltd, Yokohama Research Laboratory, Japan,
<hiroki.satoh.yj@hitachi.com>
o Thierry Lys, ERDF, France, <thierry.lys@erdfdistribution.fr>
o Jiazi Yi, LIX, France, <jiazi@jiaziyi.com>
21. Acknowledgments
The authors would like to acknowledge the team behind AODV [RFC3561].
The authors would also like to acknowledge the efforts of K. Kim
(picosNet Corp/Ajou University), S. Daniel Park (Samsung
Electronics), G. Montenegro (Microsoft Corporation), S. Yoo (Ajou
University) and N. Kushalnagar (Intel Corp.) for their work on an
initial version of a specification, from which this protocol is
derived.
22. References
Clausen, et al. Expires July 10, 2016 [Page 53]
Internet-Draft LOADng January 2016
22.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs
to Indicate Requirement Levels",
RFC 2119, BCP 14, March 1997.
[RFC5444] Clausen, T., Dean, J., Dearlove, C., and
C. Adjih, "Generalized Mobile Ad Hoc
Network (MANET) Packet/Message Format",
RFC 5444, February 2009.
[RFC7182] Herberg, U., Clausen, T., and C.
Dearlove, "Integrity Check Value and
Timestamp TLV Definitions for Mobile Ad
Hoc Networks (MANETs)", RFC 7182,
April 2014.
[RFC5498] Chakeres, I., "IANA Allocations for
Mobile Ad Hoc Network (MANET)
Protocols", RFC 5498, March 2009.
22.2. Informative References
[RFC6982] Sheffer, Y. and A. Farrel, "Improving
Awareness of Running Code: The
Implementation Status Section",
RFC 6982, July 2013.
[I-D.loadng-interop-report] Clausen, T., Camacho, A., Yi, J., Colin
de Verdiere, A., Igarashi, Y., Satoh,
H., Morii, Y., Heropberg, U., and C.
Lavenu, "Interoperability Report for the
Lightweight On-demand Ad hoc Distance-
vector Routing Protocol - Next
Generation (LOADng)", draft-lavenu-lln-
loadng-interoperability-report-04 (work
in progress), December 2012.
[RFC3561] Perkins, C., Belding-Royer, E., and S.
Das, "Ad hoc On-Demand Distance Vector
(AODV) Routing", RFC 3561, July 2003.
[RFC4861] Narten, T., Nordmark, E., Simpson, W.,
and H. Soliman, "Neighbor Discovery for
IP version 6 (IPv6)", RFC 4861,
September 2007.
[RFC4944] Montenegro, G., Kushalnagar, N., Hui,
Clausen, et al. Expires July 10, 2016 [Page 54]
Internet-Draft LOADng January 2016
J., and D. Culler, "Transmission of IPv6
Packets over IEEE 802.15.4 Networks",
RFC 4944, September 2007.
[RFC5148] Clausen, T., Dearlove, C., and B.
Adamson, "Jitter Considerations in
Mobile Ad Hoc Networks (MANETs)",
RFC 5148, February 2008.
[RFC6130] Clausen, T., Dean, J., and C. Dearlove,
"MANET Neighborhood Discovery Protocol
(NHDP)", RFC 6130, April 2011.
[RFC6206] Levis, P., Clausen, T., Gnawali, O., and
J. Ko, "The Trickle Algorithm",
RFC 6206, March 2011.
[RFC6621] Macker, J., "Simplified Multicast
Forwarding", RFC 6621, May 2012.
[RFC4107] Bellovin, S. and R. Housley, "Guidelines
for Cryptographic Key Management",
BCP 107, RFC 4107, June 2005.
[EUI64] IEEE, "Guidelines for 64-bit Global
Identifier (EUI-64) Registration
Authority".
[IEEE754-2008] IEEE, "IEEE 754-2008: IEEE Standard for
Floating-Point Arithmetic", 2008.
[IEEE_VTC2012] Clausen, T., Yi, J., and A. Coline de
Verdiere, "Towards AODV Version 2",
Proceedings of IEEE VTC 2012 Fall, IEEE
76th Vehicular Technology Conference,
2012.
[IEEE_WiCom2012] Yi, J., Clausen, T., and A. Coline de
Verdiere, "Efficient Data Acquisition in
Sensor Networks:Introducing (the) LOADng
Collection Tree Protocol",
Proceedings of IEEE WiCom 2012, The 8th
IEEE International Conference on
Wireless Communications, Networking and
Mobile Computing., 2012.
[IEEE_ICWITS2012] Yi, J., Clausen, T., and A. Bas, "Smart
Route Request for On-demand Route
Clausen, et al. Expires July 10, 2016 [Page 55]
Internet-Draft LOADng January 2016
Discovery in Constrained Environments",
Proceedings of IEEE ICWITS 2012, IEEE
International Conference on Wireless
Information Technology and Systems.,
2012.
Appendix A. Gateway Considerations
For the LOADng implementations running in network layer, sometimes
gateways are desired to connect to other networks. This section
specifies how to enable gateways for LOADng routing domains.
A LOADng router in a network, which is a gateway to 'the larger
Internet' MAY answer to RREQs for any destination except for
destinations within the network itself for which it MUST NOT answer
to RREQs. Consequently, a LOADng router, intended to act as a
gateway, MUST be configured with the addresses which can occur within
the network (ideally, the network is configured such that all devices
share a common prefix).
Appendix B. LOADng Control Messages using RFC5444
This section presents how the abstract LOADng messages, used
throughout this specification, are mapped into [RFC5444] messages.
B.1. RREQ-Specific Message Encoding Considerations
This protocol defines, and hence owns, the RREQ Message Type. Thus,
as specified in [RFC5444], this protocol generates and transmits all
RREQ messages, receives all RREQ messages and is responsible for
determining whether and how each RREQ message is to be processed
(updating the Information Base) and/or forwarded, according to this
specification. Table 2 specifies how RREQ messages are mapped into
[RFC5444]-elements.
+-------------------+-------------------+---------------------------+
| RREQ Element | RFC5444-Element | Considerations |
+-------------------+-------------------+---------------------------+
| RREQ.addr-length | <msg-addr-length> | Supports addresses from |
| | | 1-16 octets |
| RREQ.seq-num | <msg-seq-num> | 16 bits, hence MAXVALUE |
| | | (Section 8) is 65535. |
| | | MUST be included |
Clausen, et al. Expires July 10, 2016 [Page 56]
Internet-Draft LOADng January 2016
| RREQ.metric-type | METRIC Message | Encoded by way of the |
| | TLV | Type-Extension of a |
| | | Message-Type-specific |
| | | Message TLV of type |
| | | METRIC, defined in |
| | | Table 8. A LOADng Router |
| | | generating an RREQ (as |
| | | specified in |
| | | Section 12.1) when using |
| | | the HOP_COUNT metric, |
| | | MUST NOT add the METRIC |
| | | Message TLV to the RREQ |
| | | (in order to reduce |
| | | overhead, as the hop |
| | | count value is already |
| | | encoded in |
| | | RREQ.hop-count). LOADng |
| | | Routers receiving an RREQ |
| | | without METRIC Message |
| | | TLV assume that |
| | | RREQ.metric-type is |
| | | HOP_COUNT, and MUST not |
| | | add the METRIC Message |
| | | TLV when forwarding the |
| | | message. Otherwise, |
| | | exactly one METRIC TLV |
| | | MUST be included in each |
| | | RREQ message. |
| RREQ.route-metric | METRIC Message | Encoded as the value |
| | TLV value | field of the METRIC TLV. |
| | | (LOADng Routers |
| | | generating RREQs when |
| | | using the HOP_COUNT |
| | | metric do not need need |
| | | to add the METRIC Message |
| | | TLV, as specified above |
| | | for the RREQ.metric-type |
| | | field.) |
| RREQ.hop-limit | <msg-hop-limit> | 8 bits. MUST be included |
| | | in an RREQ message |
| RREQ.hop-count | <msg-hop-count> | 8 bits, hence |
| | | MAX_HOP_COUNT is 255. |
| | | MUST be included in an |
| | | RREQ message. |
| RREQ.originator | <msg-orig-addr> | MUST be included in an |
| | | RREQ message. |
Clausen, et al. Expires July 10, 2016 [Page 57]
Internet-Draft LOADng January 2016
| RREQ.destination | Address in | Encoded by way of an |
| | Address-Block | address in an address |
| | w/TLV | block, with which a |
| | | Message-Type-specific |
| | | Address Block TLV of type |
| | | ADDR-TYPE and with |
| | | Type-Extension |
| | | DESTINATION is |
| | | associated, defined in |
| | | Table 9. An RREQ MUST |
| | | contain exactly one |
| | | address with a TLV of |
| | | type ADDR-TYPE and with |
| | | Type-Extension |
| | | DESTINATION associated. |
+-------------------+-------------------+---------------------------+
Table 2: RREQ Message Elements
B.2. RREP-Specific Message Encoding Considerations
This protocol defines, and hence owns, the RREP Message Type. Thus,
as specified in [RFC5444], this protocol generates and transmits all
RREP messages, receives all RREP messages and is responsible for
determining whether and how each RREP message is to be processed
(updating the Information Base) and/or forwarded, according to this
specification. Table 3 describes how RREP messages are mapped into
[RFC5444]-elements.
+-------------------+-------------------+---------------------------+
| RREP Element | RFC5444-Element | Considerations |
+-------------------+-------------------+---------------------------+
| RREP.addr-length | <msg-addr-length> | Supports addresses from |
| | | 1-16 octets |
| RREP.seq-num | <msg-seq-num> | 16 bits, hence MAXVALUE |
| | | (Section 8) is 65535. |
| | | MUST be included |
Clausen, et al. Expires July 10, 2016 [Page 58]
Internet-Draft LOADng January 2016
| RREP.metric-type | METRIC Message | Encoded by way of the |
| | TLV | Type-Extension of a |
| | | Message-Type-specific |
| | | Message TLV of type |
| | | METRIC, defined in |
| | | Table 12. A LOADng |
| | | Router generating an RREP |
| | | (as specified in |
| | | Section 13.1) when using |
| | | the HOP_COUNT metric, |
| | | MUST NOT add the METRIC |
| | | Message TLV to the RREP |
| | | (in order to reduce |
| | | overhead, as the hop |
| | | count value is already |
| | | encoded in |
| | | RREP.hop-count). LOADng |
| | | Routers receiving an RREP |
| | | without METRIC Message |
| | | TLV assume that |
| | | RREP.metric-type is |
| | | HOP_COUNT, and MUST not |
| | | add the METRIC Message |
| | | TLV when forwarding the |
| | | message. Otherwise, |
| | | exactly one METRIC TLV |
| | | MUST be included in each |
| | | RREP message. |
| RREP.route-metric | METRIC Message | Encoded as the value |
| | TLV value | field of the METRIC TLV. |
| | | (LOADng Routers |
| | | generating RREPs when |
| | | using the HOP_COUNT |
| | | metric do not need need |
| | | to add the METRIC Message |
| | | TLV, as specified above |
| | | for the RREP.metric-type |
| | | field.) |
| RREP.ackrequired | FLAGS Message TLV | Encoded by way of a |
| | | Message-Type-specific |
| | | Message TLV of type |
| | | FLAGS, defined in |
| | | Table 13. A TLV of type |
| | | FLAGS MUST always be |
| | | included in an RREP |
| | | message. |
| RREP.hop-limit | <msg-hop-limit> | 8 bits. MUST be included |
| | | in an RREQ message |
Clausen, et al. Expires July 10, 2016 [Page 59]
Internet-Draft LOADng January 2016
| RREP.hop-count | <msg-hop-count> | 8 bits, hence |
| | | MAX_HOP_COUNT is 255. |
| | | MUST be included in an |
| | | RREP message. |
| RREP.originator | <msg-orig-addr> | MUST be included in an |
| | | RREP message. |
| RREP.destination | Address in | Encoded by way of an |
| | Address-Block | address in an address |
| | w/TLV | block, with which a |
| | | Message-Type-specific |
| | | Address Block TLV of type |
| | | ADDR-TYPE and with |
| | | Type-Extension |
| | | DESTINATION is |
| | | associated, defined in |
| | | Table 14. An RREP MUST |
| | | contain exactly one |
| | | address with a TLV of |
| | | type ADDR-TYPE and with |
| | | Type-Extension |
| | | DESTINATION associated. |
+-------------------+-------------------+---------------------------+
Table 3: RREP Message Elements
B.3. RREP_ACK Message Encoding
This protocol defines, and hence owns, the RREP_ACK Message Type.
Thus, as specified in [RFC5444], this protocol generates and
transmits all RREP_ACK messages, receives all RREP_ACK messages and
is responsible for determining whether and how each RREP_ACK message
is to be processed (updating the Information Base), according to this
specification. Table 4 describes how RREP_ACK Messages are mapped
into [RFC5444]-elements.
+----------------------+-------------------+------------------------+
| RREP_ACK Element | RFC5444-Element | Considerations |
+----------------------+-------------------+------------------------+
| RREP_ACK.addr-length | <msg-addr-length> | Supports addresses |
| | | from 1-16 octets |
| RREP_ACK.seq-num | <msg-seq-num> | 16 bits, hence |
| | | MAXVALUE (Section 8) |
| | | is 65535. MUST be |
| | | included |
Clausen, et al. Expires July 10, 2016 [Page 60]
Internet-Draft LOADng January 2016
| RREP_ACK.destination | Address in | Encoded by way of an |
| | Address-Block | address in an address |
| | w/TLV | block, with which a |
| | | Message-Type-specific |
| | | Address Block TLV of |
| | | type ADDR-TYPE and |
| | | with Type-Extension |
| | | DESTINATION is |
| | | associated, defined in |
| | | Table 17. An RREP_ACK |
| | | MUST contain exactly |
| | | one address with a TLV |
| | | of type ADDR-TYPE and |
| | | with Type-Extension |
| | | DESTINATION |
| | | associated. |
+----------------------+-------------------+------------------------+
Table 4: RREP_ACK Message Elements
B.4. RERR Message Encoding
This protocol defines, and hence owns, the RERR Message Type. Thus,
as specified in [RFC5444], this protocol generates and transmits all
RERR messages, receives all RERR messages and is responsible for
determining whether and how each RERR message is to be processed
(updating the Information Base) and/or forwarded, according to this
specification. Table 5 describes how RERR Messages are mapped into
[RFC5444]-elements.
+------------------------+------------------+-----------------------+
| RERR Element | RFC5444-Element | Considerations |
+------------------------+------------------+-----------------------+
| RERR.addr-length | <msg-addr-length | Supports addresses |
| | > | from 1-16 octets |
| RERR.hop-limit | <msg-hop-limit> | 8 bits. MUST be |
| | | included in an RREQ |
| | | message |
| RERR.errorcode | Address Block | According to |
| | TLV Value | Section 19.1. |
Clausen, et al. Expires July 10, 2016 [Page 61]
Internet-Draft LOADng January 2016
| RERR.unreachableAddres | Address in | Encoded by way of an |
| s | Address-Block | address in an address |
| | w/TLV | block, with which a |
| | | Message-Type-specific |
| | | Address Block TLV of |
| | | type ADDR-TYPE and |
| | | with Type-Extension |
| | | ERRORCODE is |
| | | associated, defined |
| | | in Table 20. |
| RERR.originator | <msg-orig-addr> | MUST be included in |
| | | an RERR message. |
| RERR.destination | Address in | Encoded by way of an |
| | Address-Block | address in an address |
| | w/TLV | block, with which a |
| | | Message-Type-specific |
| | | Address Block TLV of |
| | | type ADDR-TYPE and |
| | | with Type-Extension |
| | | DESTINATION is |
| | | associated, defined |
| | | in Table 20. An RERR |
| | | MUST contain exactly |
| | | one address with a |
| | | TLV of type ADDR-TYPE |
| | | and with |
| | | Type-Extension |
| | | DESTINATION |
| | | associated. |
+------------------------+------------------+-----------------------+
Table 5: RERR Message Elements
B.5. RFC5444-Specific IANA Considerations
This specification defines four Message Types, which must be
allocated from the "Message Types" repository of [RFC5444], two
Message TLV Types, which must be allocated from the "Message TLV
Types" repository of [RFC5444], and four Address Block TLV Types,
which must be allocated from the "Address Block TLV Types" repository
of [RFC5444].
B.5.1. Expert Review: Evaluation Guidelines
For the registries where an Expert Review is required, the designated
expert should take the same general recommendations into
consideration as are specified by [RFC5444].
Clausen, et al. Expires July 10, 2016 [Page 62]
Internet-Draft LOADng January 2016
B.5.2. Message Types
This specification defines four Message Type, to be allocated from
the 0-223 range of the "Message Types" namespace defined in
[RFC5444], as specified in Table 6.
+------+-----------------------------------------------+
| Type | Description |
+------+-----------------------------------------------+
| TBD1 | RREQ: Route Request Message |
| TBD1 | RREP: Route Reply Message |
| TBD1 | RREP_ACK: Route Reply Acknowledgement Message |
| TBD1 | RERR: Route Error Message |
+------+-----------------------------------------------+
Table 6: Message Type assignment
B.6. RREQ Message-Type-Specific TLV Type Registries
IANA is requested to create a registry for Message-Type-specific
Message TLVs for RREQ messages, in accordance with Section 6.2.1 of
[RFC5444], and with initial assignments and allocation policies as
specified in Table 7.
+---------+-------------+-------------------+
| Type | Description | Allocation Policy |
+---------+-------------+-------------------+
| 128 | METRIC | |
| 129-223 | Unassigned | Expert Review |
+---------+-------------+-------------------+
Table 7: RREQ Message-Type-specific Message TLV Types
Allocation of the METRIC TLV from the RREQ Message-Type-specific
Message TLV Types in Table 7 will create a new Type Extension
registry, with assignments as specified in Table 8.
+--------+------+-----------+------------------------+--------------+
| Name | Type | Type | Description | Allocation |
| | | Extension | | Policy |
+--------+------+-----------+------------------------+--------------+
| METRIC | 128 | 0 | HOP_COUNT: | |
| | | | MSG.hop-count is used | |
| | | | instead of the METRIC | |
| | | | TLV Value. MAX_DIST | |
| | | | is 255. | |
Clausen, et al. Expires July 10, 2016 [Page 63]
Internet-Draft LOADng January 2016
| METRIC | 128 | 1 | DIMENSIONLESS: A | |
| | | | 32-bit, dimensionless, | |
| | | | additive metric, | |
| | | | single precision | |
| | | | float, formatted | |
| | | | according to | |
| | | | [IEEE754-2008]. | |
| METRIC | 128 | 2-251 | Unassigned | Expert |
| | | | | Review |
| METRIC | 128 | 252-255 | Unassigned | Experimental |
+--------+------+-----------+------------------------+--------------+
Table 8: Message TLV Type assignment: METRIC
IANA is requested to create a registry for Message-Type-specific
Address Block TLVs for RREQ messages, in accordance with Section
6.2.1 of [RFC5444], and with initial assignments and allocation
policies as specified in Table 9.
+---------+-------------+-------------------+
| Type | Description | Allocation Policy |
+---------+-------------+-------------------+
| 128 | ADDR-TYPE | Expert Review |
| 129-223 | Unassigned | Expert Review |
+---------+-------------+-------------------+
Table 9: RREQ Message-Type-specific Address Block TLV Types
Allocation of the ADDR-TYPE TLV from the RREQ Message-Type-specific
Address Block TLV Types in Table 9 will create a new Type Extension
registry, with assignments as specified in Table 10.
+-----------+------+----------------+-------------+-----------------+
| Name | Type | Type Extension | Description | Allocation |
| | | | | Policy |
+-----------+------+----------------+-------------+-----------------+
| ADDR-TYPE | 128 | 0 | DESTINATION | |
| ADDR-TYPE | 128 | 2-255 | Unassigned | Expert Review |
+-----------+------+----------------+-------------+-----------------+
Table 10: Address Block TLV Type assignment: ADDR-TYPE
B.7. RREP Message-Type-Specific TLV Type Registries
IANA is requested to create a registry for Message-Type-specific
Message TLVs for RREP messages, in accordance with Section 6.2.1 of
[RFC5444], and with initial assignments and allocation policies as
specified in Table 11.
Clausen, et al. Expires July 10, 2016 [Page 64]
Internet-Draft LOADng January 2016
+---------+-------------+-------------------+
| Type | Description | Allocation Policy |
+---------+-------------+-------------------+
| 128 | METRIC | |
| 129 | FLAGS | |
| 130-223 | Unassigned | Expert Review |
+---------+-------------+-------------------+
Table 11: RREP Message-Type-specific Message TLV Types
Allocation of the METRIC TLV from the RREP Message-Type-specific
Message TLV Types in Table 11 will create a new Type Extension
registry, with assignments as specified in Table 12.
+--------+------+-----------+------------------------+--------------+
| Name | Type | Type | Description | Allocation |
| | | Extension | | Policy |
+--------+------+-----------+------------------------+--------------+
| METRIC | 128 | 0 | HOP_COUNT: | |
| | | | MSG.hop-count is used | |
| | | | instead of the METRIC | |
| | | | TLV Value. MAX_DIST | |
| | | | is 255. | |
| METRIC | 128 | 1 | DIMENSIONLESS: A | |
| | | | 32-bit, dimensionless, | |
| | | | additive metric, | |
| | | | single precision | |
| | | | float, formatted | |
| | | | according to | |
| | | | [IEEE754-2008]. | |
| METRIC | 128 | 2-251 | Unassigned | Expert |
| | | | | Review |
| METRIC | 128 | 252-255 | Unassigned | Experimental |
+--------+------+-----------+------------------------+--------------+
Table 12: Message TLV Type assignment: METRIC
Allocation of the FLAGS TLV from the RREP Message-Type-specific
Message TLV Types in Table 11 will create a new Type Extension
registry, with assignments as specified in Table 13.
Clausen, et al. Expires July 10, 2016 [Page 65]
Internet-Draft LOADng January 2016
+-------+------+-----------+---------------------------+------------+
| Name | Type | Type | Description | Allocation |
| | | Extension | | Policy |
+-------+------+-----------+---------------------------+------------+
| FLAGS | 129 | 0 | Bit 0 represents the | |
| | | | ackrequired flag (i.e., | |
| | | | ackrequired is TRUE when | |
| | | | bit 0 is set to 1 and | |
| | | | FALSE when bit 0 is 0.). | |
| | | | All other bits are | |
| | | | reserved for future use. | |
| FLAGS | 129 | 1-255 | Unassigned | Expert |
| | | | | Review |
+-------+------+-----------+---------------------------+------------+
Table 13: Message TLV Type assignment: FLAGS
IANA is requested to create a registry for Message-Type-specific
Address Block TLVs for RREP messages, in accordance with Section
6.2.1 of [RFC5444], and with initial assignments and allocation
policies as specified in Table 14.
+---------+-------------+-------------------+
| Type | Description | Allocation Policy |
+---------+-------------+-------------------+
| 128 | ADDR-TYPE | Expert Review |
| 129-223 | Unassigned | Expert Review |
+---------+-------------+-------------------+
Table 14: RREP Message-Type-specific Address Block TLV Types
Allocation of the ADDR-TYPE TLV from the RREP Message-Type-specific
Address Block TLV Types in Table 14 will create a new Type Extension
registry, with assignments as specified in Table 15.
+-----------+------+----------------+-------------+-----------------+
| Name | Type | Type Extension | Description | Allocation |
| | | | | Policy |
+-----------+------+----------------+-------------+-----------------+
| ADDR-TYPE | 128 | 0 | DESTINATION | |
| ADDR-TYPE | 128 | 1-255 | Unassigned | Expert Review |
+-----------+------+----------------+-------------+-----------------+
Table 15: Address Block TLV Type assignment: ADDR-TYPE
Clausen, et al. Expires July 10, 2016 [Page 66]
Internet-Draft LOADng January 2016
B.8. RREP_ACK Message-Type-Specific TLV Type Registries
IANA is requested to create a registry for Message-Type-specific
Message TLVs for RREP_ACK messages, in accordance with Section 6.2.1
of [RFC5444], and with initial assignments and allocation policies as
specified in Table 16.
+---------+-------------+-------------------+
| Type | Description | Allocation Policy |
+---------+-------------+-------------------+
| 128-223 | Unassigned | Expert Review |
+---------+-------------+-------------------+
Table 16: RREP_ACK Message-Type-specific Message TLV Types
IANA is requested to create a registry for Message-Type-specific
Address Block TLVs for RREP_ACK messages, in accordance with Section
6.2.1 of [RFC5444], and with initial assignments and allocation
policies as specified in Table 17.
+---------+-------------+-------------------+
| Type | Description | Allocation Policy |
+---------+-------------+-------------------+
| 128 | ADDR-TYPE | Expert Review |
| 129-223 | Unassigned | Expert Review |
+---------+-------------+-------------------+
Table 17: RREP_ACK Message-Type-specific Address Block TLV Types
Allocation of the ADDR-TYPE TLV from the RREP_ACK Message-Type-
specific Address Block TLV Types in Table 17 will create a new Type
Extension registry, with assignments as specified in Table 18.
+-----------+------+----------------+-------------+-----------------+
| Name | Type | Type Extension | Description | Allocation |
| | | | | Policy |
+-----------+------+----------------+-------------+-----------------+
| ADDR-TYPE | 128 | 0 | DESTINATION | |
| ADDR-TYPE | 128 | 2-255 | Unassigned | Expert Review |
+-----------+------+----------------+-------------+-----------------+
Table 18: Address Block TLV Type assignment: ADDR-TYPE
B.9. RERR Message-Type-Specific TLV Type Registries
IANA is requested to create a registry for Message-Type-specific
Message TLVs for RERR messages, in accordance with Section 6.2.1 of
[RFC5444], and with initial assignments and allocation policies as
Clausen, et al. Expires July 10, 2016 [Page 67]
Internet-Draft LOADng January 2016
specified in Table 19.
+---------+-------------+-------------------+
| Type | Description | Allocation Policy |
+---------+-------------+-------------------+
| 128-223 | Unassigned | Expert Review |
+---------+-------------+-------------------+
Table 19: RERR Message-Type-specific Message TLV Types
IANA is requested to create a registry for Message-Type-specific
Address Block TLVs for RERR messages, in accordance with Section
6.2.1 of [RFC5444], and with initial assignments and allocation
policies as specified in Table 20.
+---------+-------------+-------------------+
| Type | Description | Allocation Policy |
+---------+-------------+-------------------+
| 128 | ADDR-TYPE | Expert Review |
| 129-223 | Unassigned | Expert Review |
+---------+-------------+-------------------+
Table 20: RREP_ACK Message-Type-specific Address Block TLV Types
Allocation of the ADDR-TYPE TLV from the RERR Message-Type-specific
Address Block TLV Types in Table 20 will create a new Type Extension
registry, with assignments as specified in Table 21.
+-----------+------+----------------+-------------+-----------------+
| Name | Type | Type Extension | Description | Allocation |
| | | | | Policy |
+-----------+------+----------------+-------------+-----------------+
| ADDR-TYPE | 128 | 0 | DESTINATION | |
| ADDR-TYPE | 128 | 1 | ERRORCODE | |
| ADDR-TYPE | 128 | 2-255 | Unassigned | Expert Review |
+-----------+------+----------------+-------------+-----------------+
Table 21: Address Block TLV Type assignment: ADDR-TYPE
Appendix C. LOADng Control Packet Illustrations
This section presents example packets following this specification.
C.1. RREQ
RREQ messages are instances of [RFC5444] messages. This
specification requires that RREQ messages contain RREQ.msg-seq-num,
RREQ.msg-hop-limit, RREQ.msg-hop-count and RREQ.msg-orig-addr fields.
Clausen, et al. Expires July 10, 2016 [Page 68]
Internet-Draft LOADng January 2016
It supports RREQ messages with any combination of remaining message
header options and address encodings, enabled by [RFC5444] that
convey the required information. As a consequence, there is no
single way to represent how all RREQ messages look. This section
illustrates an RREQ message, the exact values and content included
are explained in the following text.
The RREQ message's four bit Message Flags (MF) field has value 15
indicating that the message header contains originator address, hop
limit, hop count, and message sequence number fields. Its four bit
Message Address Length (MAL) field has value 3, indicating addresses
in the message have a length of four octets, here being IPv4
addresses. The overall message length is 30 octets.
The message has a Message TLV Block with content length 6 octets
containing one TLV. The TLVs is of type METRIC and has a Flags octet
(MTLVF) value 144, indicating that it has a Value, a type extension,
but no start and stop indexes. The Value Length of the METRIC TLV is
2 octets.
The message has one Address Block. The Address Block contains 1
address, with Flags octet (ATLVF) value 0, hence with no Head or Tail
sections, and hence with a Mid section with length four octets. The
following TLV Block (content length 2 octets) contains one TLV. The
TLV is an ADDR_TYPE TLV with Flags octet (ATLVF) value 0, indicating
no Value and no indexes. Thus, the address is associated with the
Type ADDR_TYPE, i.e., it is the destination address of the RREQ.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RREQ | MF=15 | MAL=3 | Message Length = 30 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originator Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Limit | Hop Count | Message Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message TLV Block Length = 6 | METRIC | MTLVF = 144 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type Ext. | Value Len = 2 | Value (metric) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num Addrs = 1 | ABF = 0 | Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid | Address TLV Block Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ADDR-TYPE | ATLVF = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Clausen, et al. Expires July 10, 2016 [Page 69]
Internet-Draft LOADng January 2016
C.2. RREP
RREP messages are instances of [RFC5444] messages. This
specification requires that RREP messages contain RREP.msg-seq-num,
RREP.msg-hop-limit, RREP.msg-hop-count and RREP.msg-orig-addr fields.
It supports RREP messages with any combination of remaining message
header options and address encodings, enabled by [RFC5444] that
convey the required information. As a consequence, there is no
single way to represent how all RREP messages look. This section
illustrates an RREP message, the exact values and content included
are explained in the following text.
The RREP message's four bit Message Flags (MF) field has value 15
indicating that the message header contains originator address, hop
limit, hop count, and message sequence number fields. Its four bit
Message Address Length (MAL) field has value 3, indicating addresses
in the message have a length of four octets, here being IPv4
addresses. The overall message length is 34 octets.
The message has a Message TLV Block with content length 10 octets
containing two TLVs. The first TLV is of type METRIC and has a Flags
octet (MTLVF) value 144, indicating that it has a Value, a type
extension, but no start and stop indexes. The Value Length of the
METRIC TLV is 2 octets. The second TLV is of type FLAGS and has a
Flags octet (MTLVF) value of 16, indicating that it has a Value, but
no type extension or start and stop indexes. The Value Length of the
FLAGS TLV is 1 octet. The TLV value is 0x80 indicating that the
ackrequired flag is set.
The message has one Address Block. The Address Block contains 1
address, with Flags octet (ATLVF) value 0, hence with no Head or Tail
sections, and hence with a Mid section with length four octets. The
following TLV Block (content length 2 octets) contains one TLV. The
TLV is an ADDR_TYPE TLV with Flags octet (ATLVF) value 0, indicating
no Value and no indexes. Thus, the address is associated with the
Type ADDR_TYPE, i.e., it is the destination address of the RREP.
Clausen, et al. Expires July 10, 2016 [Page 70]
Internet-Draft LOADng January 2016
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RREP | MF=15 | MAL=3 | Message Length = 34 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originator Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Limit | Hop Count | Message Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message TLV Block Length = 10 | METRIC | MTLVF = 144 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type Ext. | Value Len = 2 | Value (metric) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FLAGS | MTLVF = 16 | Value Len = 1 | Value (0x80) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num Addrs = 1 | ABF = 0 | Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid | Address TLV Block Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ADDR-TYPE | ATLVF = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
C.3. RREP_ACK
RREP_ACK messages are instances of [RFC5444] messages. This
specification requires that RREP_ACK messages contains RREP_ACK.msg-
seq-num. It supports RREP_ACK messages with any combination of
remaining message header options and address encodings, enabled by
[RFC5444] that convey the required information. As a consequence,
there is no single way to represent how all RREP_ACK messages look.
This section illustrates an RREP_ACK message, the exact values and
content included are explained in the following text.
The RREP_ACK message's four bit Message Flags (MF) field has value 1
indicating that the message header contains the message sequence
number field. Its four bit Message Address Length (MAL) field has
value 3, indicating addresses in the message have a length of four
octets, here being IPv4 addresses. The overall message length is 18
octets.
The message has a Message TLV Block with content length 0 octets
containing zero TLVs.
The message has one Address Block. The Address Block contains 1
address, with Flags octet (ATLVF) value 0, hence with no Head or Tail
sections, and hence with a Mid section with length four octets. The
following TLV Block (content length 2 octets) contains one TLV. The
TLV is an ADDR_TYPE TLV with Flags octet (ATLVF) value 0, indicating
Clausen, et al. Expires July 10, 2016 [Page 71]
Internet-Draft LOADng January 2016
no Value and no indexes. Thus, the address is associated with the
Type ADDR_TYPE, i.e., it is the destination address of the RREP_ACK.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RREP_ACK | MF=1 | MAL=3 | Message Length = 18 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Sequence Number | Message TLV Block Length = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Num Addrs = 1 | ABF = 0 | Mid |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mid | Address TLV Block Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ADDR-TYPE | ATLVF = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
C.4. RERR
RERR messages are instances of [RFC5444] messages. This
specification supports RERR messages with any combination of message
header options and address encodings, enabled by [RFC5444] that
convey the required information. As a consequence, there is no
single way to represent how all RERR messages look. This section
illustrates an RERR message, the exact values and content included
are explained in the following text.
The RERR message's four bit Message Flags (MF) field has value 12
indicating that the message header contains RERR.msg-orig-addr field
and RERR.msg-hop-limit field. Its four bit Message Address Length
(MAL) field has value 3, indicating addresses in the message have a
length of four octets, here being IPv4 addresses. The overall
message length is 30 octets.
The message has a Message TLV Block with content length 0 octets
containing zero TLVs.
The message has one Address Block. The Address Block contains 2
addresses, with Flags octet (ATLVF) value 128, hence with a Head
section (with length 3 octets), but no Tail section, and hence with
Mid sections with length one octet. The following TLV Block (content
length 9 octets) contains two TLVs. The first TLV is an ADDR_TYPE
TLV with Flags octet (ATLVF) value 64, indicating a single index of
0, but no Value. Thus, the first address is associated with the Type
ADDR_TYPE and Type Extension DESTINATION, i.e., it is the destination
address of the RERR. The second TLV is an ADDR_TYPE TLV with Flags
octet (ATLVF) value 208, indicating Type Extension, Value, and single
index. Thus, the second address is associated with the Type
Clausen, et al. Expires July 10, 2016 [Page 72]
Internet-Draft LOADng January 2016
ADDR_TYPE, Type Extension ERRORCODE, and Value 0, i.e., it is
associated with error code 0.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RERR | MF=12 | MAL=3 | Message Length = 30 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originator Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Limit | Message TLV Block Length = 0 | Num Addrs = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ABF = 128 | Head Len = 3 | Head |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Head | Mid | Address TLV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Block Length= 9| ADDR-TYPE | ATLVF = 64 | Index = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ADDR-TYPE | ATLVF = 208 |TypEx=ERRORCODE| Index = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value Len = 1 | Value = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Authors' Addresses
Thomas Heide Clausen
LIX, Ecole Polytechnique
Phone: +33 6 6058 9349
EMail: T.Clausen@computer.org
URI: http://www.ThomasClausen.org/
Axel Colin de Verdiere
LIX, Ecole Polytechnique
Phone: +33 6 1264 7119
EMail: axel@axelcdv.com
URI: http://www.axelcdv.com/
Clausen, et al. Expires July 10, 2016 [Page 73]
Internet-Draft LOADng January 2016
Jiazi Yi
LIX, Ecole Polytechnique
Phone: +33 1 6933 4031
EMail: jiazi@jiaziyi.com
URI: http://www.jiaziyi.com/
Afshin Niktash
Maxim Integrated Products
Phone: +1 94 9450 1692
EMail: afshin.niktash@maxim-ic.com
URI: http://www.Maxim-ic.com/
Yuichi Igarashi
Hitachi, Ltd., Yokohama Research Laboratory
Phone: +81 45 860 3083
EMail: yuichi.igarashi.hb@hitachi.com
URI: http://www.hitachi.com/
Hiroki Satoh
Hitachi, Ltd., Yokohama Research Laboratory
Phone: +81 44 959 0205
EMail: hiroki.satoh.yj@hitachi.com
URI: http://www.hitachi.com/
Ulrich Herberg
Fujitsu Laboratories of America
Phone: +1 408 530 4528
EMail: ulrich@herberg.name
URI: http://www.herberg.name/
Cedric Lavenu
EDF R&D
Phone: +33 1 4765 2729
EMail: cedric-2.lavenu@edf.fr
URI: http://www.edf.fr/
Clausen, et al. Expires July 10, 2016 [Page 74]
Internet-Draft LOADng January 2016
Thierry Lys
ERDF
Phone: +33 1 8197 6777
EMail: thierry.lys@erdfdistribution.fr
URI: http://www.erdfdistribution.fr/
Justin Dean
Naval Research Laboratory
EMail: jdean@itd.nrl.navy.mil
URI: http://cs.itd.nrl.navy.mil/
Clausen, et al. Expires July 10, 2016 [Page 75]
