Internet DRAFT - draft-yi-manet-olsrv2-multipath
draft-yi-manet-olsrv2-multipath
Network Working Group J. Yi
Internet-Draft LIX, Ecole Polytechnique
Intended status: Experimental B. Parrein
Expires: January 30, 2015 University of Nantes
July 29, 2014
Multi-path Extension for the Optimized Link State Routing Protocol
version 2 (OLSRv2)
draft-yi-manet-olsrv2-multipath-02
Abstract
This document specifies a multi-path extension to the Optimized Link
State Routing Protocol version 2 (OLSRv2) to discover multiple
disjoint paths, so as to improve reliability of the OLSRv2 protocol.
The interoperability with OLSRv2 is retained.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on January 30, 2015.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Motivation and Experiments to Be Conducted . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Applicability Statement . . . . . . . . . . . . . . . . . . . 5
4. Protocol Overview and Functioning . . . . . . . . . . . . . . 6
5. Parameters and Constants . . . . . . . . . . . . . . . . . . . 6
5.1. Router Parameters . . . . . . . . . . . . . . . . . . . . 6
6. Packets and Messages . . . . . . . . . . . . . . . . . . . . . 7
6.1. HELLO and TC messages . . . . . . . . . . . . . . . . . . 7
6.1.1. MP_OLSRv2 TLV . . . . . . . . . . . . . . . . . . . . 7
6.2. Datagram . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.2.1. Source Routing Header in IPv4 . . . . . . . . . . . . 7
6.2.2. Source Routing Header in IPv6 . . . . . . . . . . . . 8
7. Information Bases . . . . . . . . . . . . . . . . . . . . . . 8
7.1. MP-OLSRv2 Router Set . . . . . . . . . . . . . . . . . . . 8
7.2. Multi-path Routing Set . . . . . . . . . . . . . . . . . . 8
8. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 9
8.1. HELLO and TC Message Generation . . . . . . . . . . . . . 9
8.2. HELLO and TC Message Processing . . . . . . . . . . . . . 9
8.3. Datagram Processing at the MP-OLSRv2 Originator . . . . . 10
8.4. Multi-path Dijkstra Algorithm . . . . . . . . . . . . . . 10
8.5. Datagram Forwarding . . . . . . . . . . . . . . . . . . . 11
9. Configuration Parameters . . . . . . . . . . . . . . . . . . . 12
10. Implementation Status . . . . . . . . . . . . . . . . . . . . 12
10.1. Multi-path extension based on nOLSRv2 . . . . . . . . . . 13
10.2. Multi-path extension based on olsrd . . . . . . . . . . . 13
10.3. Multi-path extension based on umOLSR . . . . . . . . . . . 13
11. Security Considerations . . . . . . . . . . . . . . . . . . . 14
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
12.1. HELLO Message-Type-Specific TLV Type Registries . . . . . 14
12.2. TC Message-Type-Specific TLV Type Registries . . . . . . . 14
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
13.1. Normative References . . . . . . . . . . . . . . . . . . . 15
13.2. Informative References . . . . . . . . . . . . . . . . . . 15
Appendix A. An example of Multi-path Dijkstra Algorithm . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17
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1. Introduction
The Optimized Link State Routing Protocol version 2 (OLSRv2)
[RFC7181] is a proactive link state protocol designed for use in
mobile ad hoc networks (MANETs). It generates routing messages
periodically to create and maintain a Routing Set, which contains
routing information to all the possible destinations in the routing
domain. For each destination, there exists an unique Routing Tuple,
which indicates the next hop to reach the destination.
This document specifies an extension of the OLSRv2 protocol
[RFC7181], to provide multiple disjoint paths for a source-
destination pair. Because of the characteristics of MANETs
[RFC2501], especially the dynamic topology, having multiple paths is
helpful for increasing network throughput, improving transmission
reliability and load balancing.
The Multi-path OLSRv2 (MP-OLSRv2) specified in this document uses
multi-path Dijkstra algorithm to explore multiple disjoint paths from
source to the destination based on the topology information obtained
through OLSRv2, and forward the datagrams in a load-balancing manner
using source routing. MP-OLSRv2 is designed to be interoperable with
OLSRv2.
1.1. Motivation and Experiments to Be Conducted
This document is an experimental extension of OLSRv2 that can
increase the data forwarding reliability in dynamic and high-load
MANET scenarios by transmitting packet over multiple disjoint paths
using source routing. This mechanism is used because:
o Disjoint paths can avoid single route failure.
o By having control of that paths at the source, the delay can be
provisioned.
o Certain scenarios require some routers must (or must not) be used.
o An very important application of this extension is combination
with Forward Error Correction coding. This requires disjoint
paths. The single path routing is not adapted because the packet
drop is normally continuous, in which forward correction coding is
not helpful.
While existed deployments, running code and simulations have proven
the interest of multipath extension for OLSRv2 in certain networks,
more experiments and experiences are still needed to understand the
mechanisms of the protocol. The multipath extension for OLSRv2 is
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expected to be revised and improved to the Standard Track, once
sufficient operational experience is obtained. Other than the
general experiences including the protocol specification,
interoperability with original OLSRv2 implementations, the
experiences in the following aspects are highly appreciated:
o Optimal values for the number of multiple paths (NUMBER_OF_PATHS)
to be used. This depends on the network topology and router
density.
o Optimal values for the cost functions. Cost functions are applied
to punish the costs of used links and nodes so as to obtain
disjoint paths. What kind of disjointness is desired (node-
disjoint or link-disjoint) may depends on the layer 2 protocol
used, and can be achieved by setting different sets of cost
functions.
o Optimal choice of "key" routers for loose source routing. In some
cases, loose source routing is use to reduce overhead or for
interoperability with OLSRv2. Other than the basic rules defined
in the following of this document, optimal choices of routers to
put in the source routing header can be further studied.
o Use of other metric other than hop-count. This multipath
extension can be used not only for hop-count metric type, but
other metric types that meet the requirement of OLSRv2, such as
[I-D.ietf-manet-olsrv2-dat-metric]. The metric type used has also
co-relation with the choice of cost functions as indicated in the
previous bullet.
o The impacts to the delay variation due to multi-path routing.
[RFC2991] brings out some concerns of multi-path routing,
especially variable latencies. Although current experiments
result show that multi-path routing can reduce the jitter in
dynamic scenarios, some transport protocols or applications may be
sensitive to the packet re-ordering.
o The disjoint multiple path protocol has interesting application
with Forward Error Correction (FEC) Coding, especially for
services like video/audio streaming. The combination of FEC
coding mechanisms and this extension is thus encouraged.
o In addition to IP source routing based approach, it can be
interesting to try multi-path routing in MANET using label-
switched flow in the future.
o The usage of multi-topology information. By using
[I-D.ietf-manet-olsrv2-multitopology], multiple topologies using
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different metric types can be obtained. It is encouraged to
experiment the use of multiple metrics for building multiple paths
also.
2. Terminology
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].
This document uses the terminology and notation defined in [RFC5444],
[RFC6130], [RFC7181]. Additionally, it defines the following
terminology:
OLSRv2 Routing Process - The routing process based on [RFC7181],
without multi-path extension specified in this document.
MP-OLSRv2 Routing Process - The routing process based on this
specification as an extension to [RFC7181].
3. Applicability Statement
As an extension of OLSRv2, this specification is applicable to MANETs
for which OLSRv2 is applicable (see [RFC7181]). It can operate on
single, or multiple interfaces, to discover multiple disjoint paths
from a source router to a destination router.
MP-OLSRv2 is specially designed for networks with dynamic topology
and slow data rate links. By providing multiple paths, higher
aggregated bandwidth can be obtained, and the routing process is more
robust to packet loss.
In a router supporting MP-OLSRv2, MP-OLSRv2 does not necessarily
replace OLSRv2 completely. The extension can be applied for certain
applications that are suitable for multi-path routing (mainly video
or audio streams), based on the information such as DiifServ Code
Point [RFC2474].
Compared to OLSRv2, this extension does not introduce new message
type in the air, and is interoperable with OLSRv2 implementations
that do not have this extension.
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4. Protocol Overview and Functioning
This specification requires OLSRv2 [RFC7181] to:
o Identify all the reachable routers in the network.
o Identify a sufficient subset of links in the networks, so that
routes can be calculated to all reachable destinations.
o Provide a Routing Set containing shortest routes from this router
to all destinations.
Based on the above information acquired by OLSRv2, the MP-OLSRv2
Routing Process is able to calculate multiple paths to certain
destinations based on multi-path Dijkstra algorithm: the Dijkstra
algorithm is performed multiple times . In each iteration, the cost
of used links are increased (i.e., punished), so that they can be
avoided to be chosen in the next iteration. The multi-path Dijkstra
algorithm can generate multiple disjoint paths from a source to a
destination , and such information is kept in Multi-path Routing Set.
The algorithm is invoked on demand, i.e., only when there is data
traffic to be sent from the source to the destination, and there is
no available routing tuples in the Multi-path Routing Set.
The datagram is forwarded based on source routing. When there is a
datagram to be sent to a destination, the source router acquires a
path from the Multi-path Routing Set (in Round-Robin fashion here) .
The path information is stored in the datagram header as source
routing header. The intermediate routers listed in the source
routing header (SRH) read the SRH and forward the datagram to the
next hop indicated in the SRH.
5. Parameters and Constants
In addition to the parameters and constants defined in [RFC7181],
this specification uses the parameters and constants described in
this section.
5.1. Router Parameters
NUMBER_OF_PATHS The number of paths desired by the router.
MAX_SRC_HOPS The maximum number of hops allowed to put in the
source routing header.
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fp Incremental function of multi-path Dijkstra algorithm. It is
used to increase costs of links belonging to the previously
computed path.
fe Incremental function of multi-path Dijkstra algorithm. It is
used to increase costs of links who lead to routers of the
previous computed path.
MR_HOLD_TIME It is the minimal time that a Multi-path Routing Tuple
SHOULD be kept in the Multi-path Routing Set.
MP_OLSR_HOLD_TIME It is the minimal time that a MP-OLSRv2 Router
Tuple SHOULD be kept in the MP-OLSRv2 Router Set.
6. Packets and Messages
This extension employs the routing control messages HELLO and TC
(Topology Control) as defined in OLSRv2 [RFC7181]. To support source
routing, a source routing header is added to each datagram routed by
this extension. Depending on the IP version used, the source routing
header is defined in following of this section.
6.1. HELLO and TC messages
HELLO and TC messages used by MP-OLSRv2 Routing Process share the
same format as defined in [RFC7181]. In addition, one Message TLV is
defined, to identify the originator of the HELLO or TC message is
running MP-OLSRv2.
6.1.1. MP_OLSRv2 TLV
An MP_OLSRv2 TLV is a Message TLV that signals the message is
generated by an MP-OLSRv2 Routing Process. It does not include any
value.
Every HELLO or TC message generated by MP-OLSRv2 Routing Process MUST
has one MP_OLSRv2 TLV.
6.2. Datagram
6.2.1. Source Routing Header in IPv4
In IPv4 [RFC0791] networks, the MP-OLSRv2 routing process employs
loose source routing, as defined in [RFC0791]. It exists as an
option header, with option class 0, and option number 3.
The source route information is kept in the "route data" field of the
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loss source route header.
6.2.2. Source Routing Header in IPv6
In IPv6 [RFC2460] networks, the MP-OLSRv2 routing process employs the
source routing header as defined in [RFC6554], with IPv6 Routing Type
3.
The source route information is kept in the "Addresses" field of the
routing header.
7. Information Bases
Each MP-OLSRv2 routing process maintains the information bases as
defined in [RFC7181]. Additionally, two more information bases are
defined for this specification.
7.1. MP-OLSRv2 Router Set
The MP-OLSRv2 Router Set recordes the routers running the MP-OLSRv2
Routing Process. It consists of MP-OLSRv2 Router Tuples:
(MP_OLSR_addr, MP_OLSR_valid_time)
where:
MP_OLSR_addr - it is the network address of the router that runs
MP-OLSRv2 Routing Process;
MP_OLSR_valid_time - it is the time until which the MP-OLSRv2
Router Tuples is considered valid.
7.2. Multi-path Routing Set
The Multi-path Routing Set records the full path information of
different paths to the destination. It consists of Multi-path
Routing Tuples:
(MR_dest_addr, MR_valid_time, MR_path_set)
where:
MR_dest_addr - it is the network address of the destination, either
the network address of an interface of a destination router or the
network address of an attached network;
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MR_valid_time - it is the time until which the Multi-path Routing
Tuples is considered valid;
MP_path_set - it contains the multiple paths to the destination.
It consists of Path Tuples.
Each Path Tuple is defined as:
(PT_cost, PT_address[1], PT_address[2], ..., PT_address[n])
where:
PT_cost - the cost of the path to the destination;
PT_address[1...n] - the addresses of intermediate router to be
visited numbered from 1 to n.
8. Protocol Details
This protocol is based on OLSRv2, and extended to discover multiple
disjoint paths from the source to the destination router. It retains
the basic routing control packets formats and processing of OLSRv2 to
obtain topology information of the network. The main differences
between OLSRv2 routing process is the datagram processing at the
source router and datagram forwarding.
8.1. HELLO and TC Message Generation
HELLO and TC messages are generated according to the section 15.1 or
section 16.1 of [RFC7181].
A single Message-Type-Specific TLV with Type := MP_OLSRv2 is added to
the message.
8.2. HELLO and TC Message Processing
HELLO and TC messages are processed according to the section 15.3 and
16.3 of [RFC7181].
For every HELLO or TC message received, if there exists a TLV with
Type := MP_OLSRv2, create or update (if the tuple exists already) the
MP-OLSR Router Tuple with
o MP_OLSR_addr = originator of the HELLO or TC message
and set the MP_OLSR_valid_time := current_time + MP_OLSR_HOLD_TIME.
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8.3. Datagram Processing at the MP-OLSRv2 Originator
When the MP-OLSRv2 routing process receives a datagram from upper
layers or interfaces connecting other routing domains, find the
Multi-path Routing Tuple where:
o MR_dest_addr = destination of the datagram, and
o MR_valid_time < current_time.
If a matching Multi-path Routing Tuple is found, a Path Tuple is
chosen from the MR_path_set in Round-robin fashion (if there are
multiple datagrams to be sent). Or else, the Multi-path Dijkstra
Algorithm defined in Section 8.4 is invoked, to generate the desired
Multi-path Routing Tuple.
The addresses in PT_address[1...n] of the chosen Path Tuple are thus
added to the datagram header in order as source routing header,
following the rules:
o Only the addresses exist in MP-OLSR Router Set can be added to the
source routing header.
o If the length of the path (n) is greater than MAX_SRC_HOPS, only
the key routers in the path are kept. By default, the key routers
are uniformly chosen in the path.
o The routers with higher priority (such as higher willingness of
routing) are preferred.
o The routers that are considered not appropriate for forwarding
indicated by external policies should be avoided.
8.4. Multi-path Dijkstra Algorithm
The Multi-path Dijkstra Algorithm is invoked when there is no
available Multi-path Routing Tuple to a desired destination d. The
general principle of the algorithm is at step i to look for the
shortest path Pi to the destination d. Based on Dijkstra algorithm,
the main modification consists in adding two cost functions namely
incremental functions fp and fe in order to prevent the next steps to
use similar path. fp is used to increase costs of arcs belonging to
the previously path Pi (or which opposite arcs belong to it). This
encourages future paths to use different arcs but not different
vertices. fe is used to increase costs of the arcs who lead to
vertices of the previous path Pi. It is possible to choose different
fp and fe to get link-disjoint path or node-disjoint routes as
necessary. A recommendation of configuration of fp and fe is given
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in Section 5.
To get NUMBER_OF_PATHS distinct paths, for each path Pi (i = 1, ...,
NUMBER_OF_PATHS) do:
1. Run Dijkstra algorithm to get the shortest path Pi for the
destination d.
2. Apply cost function fp to the links in Pi.
3. Apply cost function fe to the links who lead to routers used in
P.
A simple example of Multi-path Dijkstra Algorithm is illustrated in
Appendix A.
By invoking the algorithm depicted above, NUMBER_OF_PATHS distinct
paths is obtained, and added to the Multi-path Routing Set, by
creating a Multi-path Routing Tuple with:
o MR_dest_addr := destination d
o MR_valid_time := current time + MR_HOLD_TIME
o Each Path Tuple in the MP_path_set corresponds to a path obtained
in multi-path Dijkstra algorithm, with PT_cost := cost of the path
to the destination d.
8.5. Datagram Forwarding
On receiving a datagram with source routing header, the Destination
Address field of the IP header is first compared to the addresses of
the local interfaces. If no matching address is found, the datagram
is forwarded according OLSRv2 routing process. If a matching local
address if found, the datagram is processed as follows:
1. Obtain the next source address Address[i] in the source route
header. How to obtain the next source address depends on the IP
version used. In IPv4, the position of the next source address
is indicated by the "pointer" field of the source routing header
[RFC0791]. In IPv6, the position is indicated by "Segments Left"
field of the source routing header. If no next source address is
found, the forwarding process is finished.
2. Swap Address[i] and destination address in the IP header.
3. Forward the datagram to the destination address according to the
OLSRv2 Routing Tuple information through R_local_iface_addr where
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* R_dest_addr = destination address in the IP header
9. Configuration Parameters
This section gives default values and guideline for setting
parameters defined in Section 5. Network administrator may wish to
change certain, or all the parameters for different network
scenarios. As an experimental track protocol, the users of this
protocol are also encouraged to explore different parameter setting
in various network environments, and provide feedback.
o NUMBER_OF_PATHS = 3. This parameter defines the number of
parallel paths used in datagram forwarding. Setting it to one
makes the specification identical to OLSRv2. Setting it to too
big value can lead to unnecessary computational overhead and
inferior paths.
o MAX_SRC_HOPS = 10.
o MR_HOLD_TIME = 10 seconds.
o fp(c) = 4*c, where c is the original cost of the link.
o fe(c) = 2*c, where c is the original cost of the link.
The setting of cost functions fp and fc defines the preference of
obtained multiple disjoint paths. If id is the identity functions, 3
cases are possible:
o if id=fe<fp paths tend to be link disjoint;
o if id<fe=fp paths tend to be node-disjoint;
o if id<fe<fp paths also tend to be node-disjoint, but when is not
possible they tend to be arc disjoint.
10. 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
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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".
Until April 2014, there are 3 open source implementations of the
protocol specified in this document, for both testbed and simulation
use.
10.1. Multi-path extension based on nOLSRv2
The implementation is conducted by University of Nantes, France, and
is based on Niigata University's nOLSRv2 implementation. It is an
open source implementation. The code is available at
http://jiaziyi.com/index.php/research-projects/mp-olsr .
It can be used for Qualnet simulations, and be exported to run in
testbed. All the specification is implemented in this
implementation.
Implementation experience and test data can be found at [ADHOC11].
10.2. Multi-path extension based on olsrd
The implementation is conducted under SEREADMO (Securite des Reseaux
Ad Hoc & Mojette) project, and supported by French research agency
(RNRT2803). It is based on olsrd (http://www.olsr.org/)
implementation, and is open sourced. The code is available at
http://jiaziyi.com/index.php/research-projects/sereadmo .
The implementation is for testing the specification in the field.
All the specification is implemented in this implementation.
Implementation experience and test data can be found at [ADHOC11].
10.3. Multi-path extension based on umOLSR
The implementation is conducted by University of Nantes, France, and
is based on um-olsr implementation
(http://masimum.inf.um.es/fjrm/development/um-olsr/). The code is
available at http://jiaziyi.com/index.php/research-projects/mp-olsr
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under GNU GPL license.
The implementation is just for network simulation for NS2 network
simulator. All the specification is implemented in this
implementation.
Implementation experience and test data can be found at [WCNC08].
11. Security Considerations
This document does currently not specify any security
considerations....
12. IANA Considerations
This specification defines two Message TLV Types, which must be
allocated from the Message TLV Types repository of [RFC5444].
12.1. HELLO Message-Type-Specific TLV Type Registries
IANA is requested to create a registry for Message-Type-Specific
Message TLV for HELLO messages, in accordance with Section 6.2.1 of
[RFC5444], and with initial assignments and allocation policies as
specified in Table 1.
+---------+-------------+-------------------+
| Type | Description | Allocation Policy |
+---------+-------------+-------------------+
| 128 | MP_OLSRv2 | |
| 129-223 | Unassigned | Expert Review |
+---------+-------------+-------------------+
Table 1: HELLO Message-Type-specific Message TLV Types
12.2. TC Message-Type-Specific TLV Type Registries
IANA is requested to create a registry for Message-Type-Specific
Message TLV for TC messages, in accordance with Section 6.2.1 of
[RFC5444], and with initial assignments and allocation policies as
specified in Table 2.
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+---------+-------------+-------------------+
| Type | Description | Allocation Policy |
+---------+-------------+-------------------+
| 128 | MP_OLSRv2 | |
| 129-223 | Unassigned | Expert Review |
+---------+-------------+-------------------+
Table 2: TC Message-Type-specific Message TLV Types
13. References
13.1. Normative References
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
September 1981.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5444] Clausen, T., Dearlove, C., Dean, J., and C. Adjih,
"Generalized Mobile Ad Hoc Network (MANET) Packet/Message
Format", RFC 5444, February 2009.
[RFC6130] Clausen, T., Dearlove, C., and J. Dean, "Mobile Ad Hoc
Network (MANET) Neighborhood Discovery Protocol (NHDP)",
RFC 6130, April 2011.
[RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6
Routing Header for Source Routes with the Routing Protocol
for Low-Power and Lossy Networks (RPL)", RFC 6554,
March 2012.
[RFC7181] Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg,
"The Optimized Link State Routing Protocol Version 2",
RFC 7181, April 2014.
13.2. Informative References
[ADHOC11] Yi, J., Adnane, A-H., David, S., and B. Parrein,
"Multipath optimized link state routing for mobile ad hoc
networks", In Elsevier Ad Hoc Journal, vol.9, n. 1, 28-47,
January, 2011.
[I-D.ietf-manet-olsrv2-dat-metric]
Rogge, H. and E. Baccelli, "Packet Sequence Number based
directional airtime metric for OLSRv2",
draft-ietf-manet-olsrv2-dat-metric-01 (work in progress),
Yi & Parrein Expires January 30, 2015 [Page 15]
Internet-Draft Multi-Path OLSRv2 July 2014
July 2014.
[I-D.ietf-manet-olsrv2-multitopology]
Dearlove, C. and T. Clausen, "Multi-Topology Extension for
the Optimized Link State Routing Protocol version 2
(OLSRv2)", draft-ietf-manet-olsrv2-multitopology-04 (work
in progress), July 2014.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
December 1998.
[RFC2501] Corson, M. and J. Macker, "Mobile Ad hoc Networking
(MANET): Routing Protocol Performance Issues and
Evaluation Considerations", RFC 2501, January 1999.
[RFC2991] Thaler, D. and C. Hopps, "Multipath Issues in Unicast and
Multicast Next-Hop Selection", RFC 2991, November 2000.
[RFC6982] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", RFC 6982,
July 2013.
[WCNC08] Yi, J., Cizeron, E., Hamma, S., and B. Parrein,
"Simulation and performance analysis of MP-OLSR for mobile
ad hoc networks", In Proceeding of IEEE Wireless
Communications and Networking Conference, 2008.
Appendix A. An example of Multi-path Dijkstra Algorithm
This appendix gives an example of multi-path Dijkstra algorithm. The
network topology is depicted in Figure 1.
.-----2-----.
/ / \ \
/ / \ \
1 / \ 5
\ / \ /
\ / \ /
3-----------4
Figure 1: Network Topology for the on-demand example
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Internet-Draft Multi-Path OLSRv2 July 2014
The initial cost of all the links is set to 1. The incremental
functions fp and fe are defined as fp(c)=4c and fe(c)=2c in this
example. Two routes from node 1 to node 5 are demanded.
On the first run of the Dijkstra algorithm, the shortest path 1->2->5
with cost 2 is obtained.
The incremental function fp is applied to increase the cost of the
link 1-2 and 2-5, from 1 to 4. fe is applied to increase the cost of
the link 1-3, 2-3, 2-4, 4-5, from 1 to 2.
On the second run of the Dijkstra algorithm, the second path
1->3->4->5 with cost 5 is obtained.
Authors' Addresses
Jiazi Yi
LIX, Ecole Polytechnique
91128 Palaiseau Cedex,
France
Phone: +33 1 77 57 80 85
Email: jiazi@jiaziyi.com
URI: http://www.jiaziyi.com/
Benoit Parrein
University of Nantes
IRCCyN lab - IVC team
Polytech Nantes, rue Christian Pauc, BP50609
44306 Nantes cedex 3
France
Phone: +33 (0) 240 683 050
Email: Benoit.Parrein@polytech.univ-nantes.fr
URI: http://www.irccyn.ec-nantes.fr/~parrein
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