Internet DRAFT - draft-ietf-tsvwg-rsvp-pcn
draft-ietf-tsvwg-rsvp-pcn
Internet Engineering Task Force Georgios Karagiannis
Internet-Draft Huawei Technologies
Intended status: Experimental Anurag Bhargava
Expires: April 6, 2015 Cisco Systems, Inc.
October 6, 2014
Generic Aggregation of Resource ReSerVation Protocol (RSVP)
for IPv4 And IPv6 Reservations over PCN domains
draft-ietf-tsvwg-rsvp-pcn-11
Abstract
This document specifies extensions to Generic Aggregated RSVP
RFC 4860 for support of the PCN Controlled Load (CL) and Single
Marking (SM) edge behaviors over a Diffserv cloud using Pre-
Congestion Notification.
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
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
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 6, 2015.
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Copyright Notice
Copyright (c) 2014 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
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Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Objective . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Overview and Motivation . . . . . . . . . . . . . . . . . . . 5
1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.4. Organization of This Document . . . . . . . . . . . . . . . . 11
2. Overview of RSVP extensions and Operations . . . . . . . . . . . 11
2.1. Overview of RSVP Aggregation Procedures in PCN domains . . . . . 11
2.2. PCN Marking and encoding and transport of pre-congestion
Information . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3. Traffic Classification Within The Aggregation Region . . . . . . 13
2.4. Deaggregator (PCN-egress-node) Determination . . . . . . . . . . 13
2.5. Mapping E2E Reservations Onto Aggregate Reservations . . . . . . 13
2.6 Size of Aggregate Reservations . . . . . . . . . . . . . . . . . 14
2.7. E2E Path ADSPEC update . . . . . . . . . . . . . . . . . . . . . 14
2.8. Intra-domain Routes . . . . . . . . . . . . . . . . . . . . . . .14
2.9. Inter-domain Routes . . . . . . . . . . . . . . . . . . . . . . 15
2.10. Reservations for Multicast Sessions . . . . . . . . . . . . . . 15
2.11. Multi-level Aggregation . . . . . . . . . . . . . . . . . . . . 15
2.12. Reliability Issues . . . . . . . . . . . . . . . . . . . . . . 15
3. Elements of Procedure . . . . . . . . . . . . . . . . . . . . . . 15
3.1. Receipt of E2E Path Message by PCN-ingress-node
(aggregating router) . . . . . . . . . . . . . . . . . . . . . . 15
3.2. Handling Of E2E Path Message by Interior Routers . . . . . . . 16
3.3. Receipt of E2E Path Message by PCN-egress-node
(deaggregating router) . . . . . . . . . . . . . . . . . . . . . 16
3.4. Initiation of new Aggregate Path Message By PCN-ingress-node
(Aggregating Router) . . . . . . . . . . . . . . . . . . . . . 16
3.5. Handling Of new Aggregate Path Message by Interior Routers . . 16
3.6 Handling Of Aggregate Path Message by Deaggregating Router . . 16
3.7. Handling of E2E Resv Message by Deaggregating Router . . . . . 17
3.8. Handling Of E2E Resv Message by Interior Routers . . . . . . . 17
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3.9. Initiation of New Aggregate Resv Message By Deaggregating Router 17
3.10. Handling of Aggregate Resv Message by Interior Routers . . . 18
3.11. Handling of E2E Resv Message by Aggregating Router . . . . . . 18
3.12. Handling of Aggregated Resv Message by Aggregating Router . . 18
3.13. Removal of E2E Reservation . . . . . . . . . . . . . . . . . . 19
3.14. Removal of Aggregate Reservation . . . . . . . . . . . . . . . 19
3.15. Handling of Data On Reserved E2E Flow by Aggregating Router . 19
3.16. Procedures for Multicast Sessions . . . . . . . . . . . . . . 19
3.17. Misconfiguration of PCN node . . . . . . . . . . . . . . . . 19
3.18. PCN based Flow Termination . . . . . . . . . . . . . . . . . 19
4. Protocol Elements . . . . . . . . . . . . . . . . . . . . . . . . 20
4.1 PCN object . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5. Security Considerations . . . . . . . . . . . . . . . . . . . . . 23
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 24
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 24
8. Normative References . . . . . . . . . . . . . . . . . . . . . . 24
9. Informative References . . . . . . . . . . . . . . . . . . . . . 25
10. Appendix A: Example Signaling Flow . . . . . . . . . . . . . . . 26
11. Authors' Address . . . . . . . . . . . . . . . . . . . . . . . . 29
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1. Introduction
1.1 Objective
Pre-Congestion Notification (PCN) can support the quality of service
(QoS) of inelastic flows within a Diffserv domain in a simple,
scalable, and robust fashion. Two mechanisms are used: admission
control and flow termination. Admission control is used to decide
whether to admit or block a new flow request, while flow termination
is used in abnormal circumstances to decide whether to terminate some
of the existing flows. To support these two features, the overall
rate of PCN-traffic is metered on every link in the domain, and PCN-
packets are appropriately marked when certain configured rates are
exceeded. These configured rates are below the rate of the link,
thus providing notification to boundary nodes about overloads before
any congestion occurs (hence "pre-congestion" notification). The
PCN-egress-nodes measure the rates of differently marked PCN traffic
in periodic intervals and report these rates to the Decision Points
for admission control and flow termination; the Decision Points use
these rates to make decisions. The Decision Points may be collocated
with the PCN-ingress-nodes, or their function may be implemented in a
another node. For more details see [RFC5559], [RFC6661], and
[RFC6662].
The main objective of this document is to specify the signaling
protocol that can be used within a Pre-Congestion Notification (PCN)
domain to carry reports from a PCN-ingress-node to a PCN Decision
point, considering that the PCN Decision Point and PCN-egress-node
are collocated.
If the PCN Decision Point is not collocated with the PCN-egress-node
then additional signaling procedures are required that are out of
the scope of this document. Moreover, as mentioned above this
architecture conforms with PBAC (Policy-Based Admission Control),
when the Decision Point is located in a another node then the PCN-
ingress-node [RFC2753].
Several signaling protocols can be used to carry information between
PCN-boundary-nodes (PCN-ingress-node and PCN-egress-node). However,
since (1) both PCN-egress-node and PCN-ingress-nodes are located on
the data path and (2) the admission control procedure needs to be
done at PCN-egress-node, a signaling protocol that follows the same
path as the data path, like RSVP (Resource Reservation Protocol), is
more suited for this purpose. In particular, this document specifies
extensions to Generic Aggregated RSVP [RFC4860] for support of the
PCN Controlled Load (CL) and Single Marking (SM) edge behaviors over
a Diffserv cloud using Pre-Congestion Notification.
This draft is intended to be published as Experimental in order to:
o) validate industry interest by allowing implementation and
deployment
o) gather operational experience, in particular around dynamic
interactions of RSVP signaling and PCN notification and
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corresponding levels of performance.
Support for the techniques specified in this document involves RSVP
functionality in boundary nodes of a PCN domain whose interior nodes
forward RSVP traffic without performing RSVP functionality.
1.2 Overview and Motivation
Two main Quality of Service (QoS) architectures have been specified
by the IETF. These are the Integrated Services (Intserv) [RFC1633]
architecture and the Differentiated Services (DiffServ) architecture
([RFC2475]).
Intserv provides methods for the delivery of end-to-end Quality of
Service (QoS) to applications over heterogeneous networks. One of the
QoS signaling protocols used by the Intserv architecture is the
Resource reServation Protocol (RSVP) [RFC2205], which can be used by
applications to request per-flow resources from the network. These
RSVP requests can be admitted or rejected by the network.
Applications can express their quantifiable resource requirements
using Intserv parameters as defined in [RFC2211] and [RFC2212]. The
Controlled Load (CL) service [RFC2211] is a quality of service (QoS)
closely approximating the QoS that the same flow would receive from a
lightly loaded network element. The CL service is useful for
inelastic flows such as those used for real-time media.
The DiffServ architecture can support the differentiated treatment of
packets in very large scale environments. While Intserv and RSVP
classify packets per-flow, Diffserv networks classify packets into
one of a small number of aggregated flows or "classes", based on the
Diffserv codepoint (DSCP) in the packet IP header. At each Diffserv
router, packets are subjected to a "per-hop behavior" (PHB), which is
invoked by the DSCP. The primary benefit of Diffserv is its
scalability, since the need for per-flow state and per-flow
processing, is eliminated.
However, DiffServ does not include any mechanism for communication
between applications and the network. Several solutions have been
specified to solve this issue. One of these solutions is Intserv over
Diffserv [RFC2998] including resource-based admission control (RBAC),
PBAC, assistance in traffic identification/classification, and
traffic conditioning. Intserv over Diffserv can operate over a
statically provisioned or a RSVP aware Diffserv region. When it is
RSVP aware, several mechanisms may be used to support dynamic
provisioning and topology-aware admission control, including
aggregate RSVP reservations, per-flow RSVP, or a bandwidth broker.
[RFC3175] specifies aggregation of Resource ReSerVation Protocol
(RSVP) end-to-end reservations over aggregate RSVP reservations. In
[RFC3175] the RSVP generic aggregated reservation is characterized by
a RSVP SESSION object using the 3-tuple <source IP address,
destination IP address, Diffserv Code Point>.
Several scenarios require the use of multiple generic aggregate
reservations that are established for a given PHB from a given source
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IP address to a given destination IP address, see [SIG-NESTED],
[RFC4860]. For example, multiple generic aggregate reservations
can be applied in the situation that multiple E2E reservations using
different preemption priorities need to be aggregated through a PCN-
domain using the same PHB. By using multiple aggregate reservations
for the same PHB, it allows enforcement of the different preemption
priorities within the aggregation region. This allows more efficient
management of the Diffserv resources, and in periods of resource
shortage, this allows sustainment of a larger number of E2E
reservations with higher preemption priorities. In particular,
[SIG-NESTED] discusses in detail how end-to-end RSVP reservations can
be established in a nested VPN environment through RSVP aggregation.
[RFC4860] provides generic aggregate reservations by extending
[RFC3175] to support multiple aggregate reservations for the same
source IP address, destination IP address, and PHB (or set of PHBs).
In particular, multiple such generic aggregate reservations can be
established for a given PHB from a given source IP address to a given
destination IP address. This is achieved by adding the concept of a
Virtual Destination Port and of an Extended Virtual Destination Port
in the RSVP SESSION object. In addition to this, the RSVP SESSION
object for generic aggregate reservations uses the PHB Identification
Code (PHB-ID) defined in [RFC3140], instead of using the Diffserv
Code Point (DSCP) used in [RFC3175]. The PHB-ID is used to identify
the PHB, or set of PHBs, from which the Diffserv resources are to be
reserved.
The RSVP like signaling protocol required to carry (1) requests from
a PCN-egress-node to a PCN-ingress-node and (2) reports from a
PCN-ingress-node to a PCN-egress-node needs to follow the PCN
signaling requirements defined in [RFC6663]. In addition to
that the signaling protocol functionality supported by the PCN-
ingress-nodes and PCN-egress-nodes needs to maintain logical
aggregate constructs (i.e. ingress-egress-aggregate state) and be
able to map E2E reservations to these aggregate constructs. Moreover,
no actual reservation state is needed to be maintained inside the PCN
domain, i.e., the PCN-interior-nodes are not maintaining any
reservation state.
This can be accomplished by two possible approaches:
Approach (1):
o) adapting the RFC 4860 aggregation procedures to fit the PCN
requirements with as little change as possible over the RFC 4860
functionality
o) hence performing aggregate RSVP signaling (even if it is to be
ignored by PCN interior nodes)
o) using this aggregate RSVP signaling procedures to carry PCN
information between the PCN-boundary-nodes (PCN-ingress-node and
PCN-egress-node).
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Approach (2):
o) adapting the RFC 4860 aggregation procedures to fit the PCN
requirements with more significant changes over RFC4860 (i.e.
the aspect of the procedures that have to do with maintaining
aggregate states and to do with mapping the E2E reservations to
aggregate constructs are kept, but the procedures that have to
do with the aggregate RSVP signaling and aggregate reservation
establishment/maintenance are dropped).
o) hence not performing aggregate RSVP signaling
o) piggy-backing of the PCN information inside the E2E RSVP
signaling.
Both approaches are probably viable, however, since the RFC 4860
operations have been thoroughly studied and implemented, it can be
considered that the RFC 4860 solution can better deal with the more
challenging situations (rerouting in the PCN domain, failure of an
PCN-ingress-node, failure of an PCN-egress-node, rerouting towards a
different edge, etc.). This is the reason for choosing Approach (1)
for the specification of the signaling protocol used to carry
PCN information between the PCN-boundary-nodes (PCN-ingress-node and
PCN-egress-node).
In particular, this document specifies extensions to Generic
Aggregated RSVP [RFC4860] for support of the PCN Controlled Load (CL)
and Single Marking (SM) edge behaviors over a Diffserv cloud using
Pre-Congestion Notification.
This document follows the PCN signaling requirements defined in
[RFC6663] and specifies extensions to Generic Aggregated RSVP
[RFC4860] for support of PCN edge behaviors as specified in
[RFC6661] and [RFC6662]. Moreover, this document specifies how RSVP
aggregation can be used to setup and maintain: (1) Ingress Egress
Aggregate (IEA) states at Ingress and Egress nodes and (2) generic
aggregation of RSVP end-to-end RSVP reservations over PCN (Congestion
and Pre-Congestion Notification) domains.
To comply with this specification, PCN-nodes MUST be able to
support the functionality specified in [RFC5670], [RFC5559],
[RFC6660], [RFC6661], [RFC6662]. Furthermore, the PCN-boundary-nodes
MUST support the RSVP generic aggregated reservation procedures
specified in [RFC4860] which are augmented with procedures specified
in this document.
1.3. Terminology
This document uses terms defined in [RFC4860], [RFC3175], [RFC5559],
[RFC5670], [RFC6661], [RFC6662].
For readability, a number of definitions from [RFC3175] as well as
definitions for terms used in [RFC5559], [RFC6661], and [RFC6662] are
provided here, where some of them are augmented with new meanings:
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Aggregator This is the process in (or associated with) the
router at the ingress edge of the aggregation region
(with respect to the end-to-end RSVP reservation)
and behaving in accordance with [RFC4860]. In this
document, it is also the PCN-ingress-node. It is
important to notice that in the context of this
document the Aggregator must be able to determine
the Deaggregator using the procedures specified in
Section 4 of [RFC4860] and in Section 1.4.2 of
[RFC3175].
Congestion level estimate (CLE):
The ratio of PCN-marked to total PCN-traffic
(measured in octets) received for a given ingress-
egress-aggregate during a given measurement period.
The CLE is used to derive the PCN-admission-state
and is also used by the report suppression procedure
if report suppression is activated.
Deaggregator This is the process in (or associated with) the
router at the egress edge of the aggregation region
(with respect to the end-to-end RSVP reservation)
and behaving in accordance with [RFC4860]. In this
document, it is also the PCN-egress-node and
Decision Point.
E2E end to end
E2E Reservation This is an RSVP reservation such that:
(i) corresponding RSVP Path messages are initiated
upstream of the Aggregator and terminated
downstream of the Deaggregator, and
(ii) corresponding RSVP Resv messages are initiated
downstream of the Deaggregator and terminated
upstream of the Aggregator, and
(iii) this RSVP reservation is aggregated over an
Ingress Egress Aggregate (IEA) between the
Aggregator and Deaggregator.
An E2E RSVP reservation may be a per-flow
reservation, which in this document is only
maintained at the PCN-ingress-node and PCN-egress-
node. Alternatively, the E2E reservation may itself
be an aggregate reservation of various types (e.g.,
Aggregate IP reservation, Aggregate IPsec
reservation, see [RFC4860]). As per regular RSVP
operations, E2E RSVP reservations are
unidirectional.
E2E microflow a microflow where its associated packets are being
forwarded on an E2E path.
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Extended vDstPort (Extended Virtual Destination Port)
An identifier used in the SESSION that remains
constant over the life of the generic aggregate
reservation. The length of this identifier is 32-
bits when IPv4 addresses are used and 128 bits when
IPv6 addresses are used.
A sender(or Aggregator) that wishes to narrow the
scope of a SESSION to the sender-receiver pair (or
Aggregator-Deaggregator pair) should place its IPv4
or IPv6 address here as a network unique
identifier. A sender (or Aggregator) that wishes to
use a common session with other senders (or
Aggregators) in order to use a shared reservation
across senders (or Aggregators) must set this field
to all zeros. In this document, the Extended
vDstPort should contain the IPv4 or IPv6 address of
the Aggregator.
ETM-rate
The rate of excess-traffic-marked PCN-traffic
received at a PCN-egress-node for a given ingress-
egress-aggregate in octets per second.
Ingress-egress-aggregate (IEA):
The collection of PCN-packets from all PCN-flows
that travel in one direction between a specific pair
of PCN-boundary-nodes. In this document one RSVP
generic aggregated reservation is mapped to only
one ingress-egress-aggregate, while one
ingress-egress-aggregate is mapped to either
one or to more than one RSVP generic aggregated
reservations. PCN-flows and their PCN-traffic that
are mapped into a specific RSVP generic aggregated
reservation can also easily be mapped into their
corresponding ingress-egress-aggregate.
Microflow: a single instance of an application-to-application
(from [RFC2474]) flow of packets which is identified by source
address, destination address, protocol id, and
source port, destination port (where applicable).
PCN-domain: a PCN-capable domain; a contiguous set of
PCN-enabled nodes that perform Diffserv scheduling
[RFC2474]; the complete set of PCN-nodes that in
principle can, through PCN-marking packets,
influence decisions about flow admission and
termination within the domain; includes the PCN-
egress-nodes, which measure these PCN-marks, and the
PCN-ingress-nodes.
PCN-boundary-node: a PCN-node that connects one PCN-domain to a node
either in another PCN-domain or in a non-PCN-domain.
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PCN-interior-node: a node in a PCN-domain that is not a PCN-
boundary-node.
PCN-node: a PCN-boundary-node or a PCN-interior-node.
PCN-egress-node: a PCN-boundary-node in its role in handling
traffic as it leaves a PCN-domain. In this
document the PCN-egress-node operates also as a
Decision Point and Deaggregator.
PCN-ingress-node: a PCN-boundary-node in its role in handling
traffic as it enters a PCN-domain. In this
document the PCN-ingress-node operates also as a
Aggregator.
PCN-traffic,
PCN-packets,
PCN-BA: a PCN-domain carries traffic of different Diffserv
behavior aggregates (BAs) [RFC2474]. The PCN-BA
uses the PCN mechanisms to carry PCN-traffic, and
the corresponding packets are PCN-packets.
The same network will carry traffic of other
Diffserv BAs. The PCN-BA is
distinguished by a combination of the Diffserv
codepoint (DSCP) and ECN fields.
PCN-flow: the unit of PCN-traffic that the PCN-boundary-node
admits (or terminates); the unit could be a single
E2E microflow (as defined in [RFC2474]) or some
identifiable collection of microflows.
PCN-admission-state:
The state ("admit" or "block") derived by the
Decision Point for a given ingress-egress-aggregate
based on statistics about PCN-packet marking. The
Decision Point decides to admit or block new flows
offered to the aggregate based on the current value
of the PCN-admission-state.
PCN-sent-rate
The rate of PCN-traffic received at a PCN-ingress-
node and destined for a given ingress-egress-
aggregate in octets per second.
PHB-ID (Per Hop Behavior Identification Code)
A 16-bit field containing the Per Hop Behavior
Identification Code of the PHB, or of the set of
PHBs, from which Diffserv resources
are to be reserved. This field must be encoded as
specified in Section 2 of [RFC3140].
RSVP generic aggregated reservation: an RSVP reservation that is
identified by using the RSVP SESSION object
for generic RSVP aggregated reservation. This RSVP
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SESSION object is based on the RSVP SESSION object
specified in [RFC4860] augmented with the following
information:
o) the IPv4 DestAddress, IPv6 DestAddress should be
set to the IPv4 or IPv6 destination addresses,
respectively, of the Deaggregator (PCN-egress-
node)
o) PHB-ID (Per Hop Behavior Identification Code)
should be set equal to PCN-compatible Diffserv
codepoint(s).
o) Extended vDstPort should be set to the IPv4 or
IPv6 destination addresses, of the Aggregator
(PCN-ingress-node)
VDstPort (Virtual Destination Port)
A 16-bit identifier used in the SESSION that
remains constant over the life of the generic
aggregate reservation.
1.4. Organization of This Document
This document is organized as follows. Section 2 gives an overview of
RSVP extensions and operations. The elements of the used procedures
are specified in Section 3. Section 4 describes the protocol
elements. The security considerations are given in section 5 and the
IANA considerations are provided in Section 6.
2. Overview of RSVP extensions and Operations
2.1 Overview of RSVP Aggregation Procedures in PCN domains
The PCN-boundary-nodes, see Figure 1, can support RSVP SESSIONS for
generic aggregated reservations {RFC4860], which are depending on
ingress-egress-aggregates. In particular, one RSVP generic aggregated
reservation matches to only one ingress-egress-aggregate.
However, one ingress-egress-aggregate matches to either
one, or more than one, RSVP generic aggregated reservations.
In addition, to comply with this specification, the PCN-boundary
nodes need to distinguish and process (1) RSVP SESSIONS for generic
aggregated sessions and their messages according to [RFC4860], (2)
E2E RSVP sessions and messages according to [RFC2205].
This document locates all RSVP processing for a PCN domain at PCN-
Boundary nodes. PCN-interior-nodes do not perform any RSVP
functionality or maintain RSVP-related state information. Rather,
PCN-interior nodes forward all RSVP messages (for both generic
aggregated reservations[RFC4860] and end to end reservations
[RFC2205]) as if they were ordinary network traffic.
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Moreover, each Aggregator and Deaggregator (i.e., PCN-boundary-nodes)
need to support policies to initiate and maintain for each pair of
PCN-boundary-nodes of the same PCN-domain one ingress-egress-
aggregate.
--------------------------
/ PCN-domain \
|----| | | |----|
H--| R |\ |-----| |------| /| R |-->H
H--| |\\| | |---| |---| | |//| |-->H
|----| \| | | I | | I | | |/ |----|
| Agg |======================>| Deag |
/| | | | | | | |\
H--------//| | |---| |---| | |\\-------->H
H--------/ |-----| |------| \-------->H
| |
\ /
--------------------------
H = Host requesting end-to-end RSVP reservations
R = RSVP router
Agg = Aggregator (PCN-ingress-node)
Deag = Deaggregator (PCN-egress-node)
I = Interior Router (PCN-interior-node)
--> = E2E RSVP reservation
==> = Aggregate RSVP reservation
Figure 1 : Aggregation of E2E Reservations
over Generic Aggregate RSVP Reservations
in PCN domains, based on [RFC4860]
Both the Aggregator and Deaggregator can maintain one or
more RSVP generic aggregated Reservations, but the Deaggregator is
the entity that initiates these RSVP generic aggregated reservations.
Note that one RSVP generic aggregated reservation matches to only
one ingress-egress-aggregate, while one ingress-egress-aggregate
matches to either one or to more than one RSVP generic aggregated
reservations. This can be accomplished by using for the different
RSVP generic aggregated reservations the same combinations of
ingress and egress identifiers, but with a different PHB-ID value
(see [RFC4860]). The procedures for aggregation of E2E reservations
over generic aggregate RSVP reservations are the same as the
procedures specified in Section 4 of [RFC4860], augmented with the
ones specified in Section 2.5.
One significant difference between this document and [RFC4860] is the
fact that in this document the admission control of E2E RSVP
reservations over the PCN core is performed according to the PCN
procedures, while in [RFC4860] this is achieved via first admitting
aggregate RSVP reservations over the aggregation region and then
admitting the E2E reservations over the aggregate RSVP reservations.
Therefore, in this document, the RSVP generic aggregate RSVP
reservations are not subject to admission control in the PCN-core,
and the E2E RSVP reservations are not subject to admission control
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over the aggregate reservations. In turn, this means that several
procedures of [RFC4860] are significantly simplified in this
document:
o) unlike [RFC4860], the generic aggregate RSVP reservations need
not be admitted in the PCN core.
o) unlike [RFC4860], the RSVP aggregated traffic does not need to
be tunneled between Aggregator and Deaggregator, see Section
2.3.
o) unlike [RFC4860], the Deaggregator need not perform admission
control of E2E reservations over the aggregate RSVP
reservations.
o) unlike [RFC4860], there is no need for dynamic adjustment of
the RSVP generic aggregated reservation size, see Section 2.6.
2.2 PCN Marking and encoding and transport of pre-congestion
information
The method of PCN marking within the PCN domain is specified in
[RFC5670]. In addition, the method of encoding and transport of pre-
congestion information is specified in [RFC6660]. The PHB-ID (Per Hop
Behavior Identification Code) used SHOULD be set equal
to PCN-compatible Diffserv codepoint(s).
2.3. Traffic Classification Within The Aggregation Region
The PCN-ingress marks a PCN-BA using PCN-marking (i.e., combination
of the DSCP and ECN fields), which interior nodes use to
classify PCN-traffic. The PCN-traffic (e.g., E2E microflows)
belonging to a RSVP generic aggregated reservation can be
classified only at the PCN-boundary-nodes (i.e., Aggregator and
Deaggregator) by using the RSVP SESSION object for RSVP generic
aggregated reservations, see Section 2.1 of [RFC4860]. Note that the
DSCP value included in the SESSION object, SHOULD be set equal
to a PCN-compatible Diffserv codepoint. Since no admission control
procedures over the RSVP generic aggregated reservations in the PCN-
core are required, unlike [RFC4860], the RSVP aggregated traffic need
not to be tunneled between Aggregator and Deaggregator. In this
document one RSVP generic aggregated reservation is mapped to only
one ingress-egress-aggregate, while one ingress-egress-aggregate is
mapped to either one or to more than one RSVP generic aggregated
reservations. PCN-flows and their PCN-traffic that are mapped into a
specific RSVP generic aggregated reservation can also easily be
classified into their corresponding ingress-egress-aggregate. The
method of traffic conditioning of PCN-traffic and non-PCN traffic and
PHB configuration is described in [RFC6661] and [RFC6662].
2.4. Deaggregator Determination
The present document assumes the same dynamic Deaggregator
determination method as used in [RFC4860].
2.5. Mapping E2E Reservations Onto Aggregate Reservations
To comply with this specification for the mapping of E2E reservations
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onto aggregate reservations, the same methods MUST be used as the
ones described in Section 4 of [RFC4860], augmented by the following
rules:
o) An Aggregator (also PCN-ingress-node in this document) or
Deaggregator (also PCN-egress-node and Decision Point in this
document) MUST use one or more policies to determine whether a
RSVP generic aggregated reservation can be mapped into an ingress-
Egress-aggregate. This can be accomplished by using for the
different RSVP generic aggregated reservations the same
combinations of ingress and egress identifiers, but with a
different PHB-ID value (see [RFC4860]) corresponding to the PCN
specifications. In particular, the RSVP SESSION object specified
in [RFC4860] augmented with the following information:
o) the IPv4 DestAddress, IPv6 DestAddress MUST be set to the
IPv4 or IPv6 destination addresses, respectively, of the
Deaggregator (PCN-egress-node), see [RFC4860]. Note that the
PCN-domain is considered as being only one RSVP hop (for
Generic aggregated RSVP or E2E RSVP). This means that the next
RSVP hop for the Aggregator in the downstream direction is the
Deaggregator and the next RSVP hop for the Deaggregator in the
upstream direction is the Aggregator.
o) PHB-ID (Per Hop Behavior Identification Code) SHOULD be set
equal to PCN-compatible Diffserv codepoint(s).
o) Extended vDstPort SHOULD be set to the IPv4 or IPv6
destination addresses, of the Aggregator (PCN-ingress-node),
see [RFC4860].
2.6. Size of Aggregate Reservations
Since:(i) no admission control of E2 reservations over the RSVP
aggregated reservations is required, and (ii) no admission control of
the RSVP aggregated reservation over the PCN core is required,
the size of the generic aggregate reservation is irrelevant and can
be set to any arbitrary value by the Deaggreagtor. The Deaggregator
SHOULD set the value of a generic aggregate reservation to a null
bandwidth. We also observe that there is no need for dynamic
adjustment of the RSVP aggregated reservation size.
2.7. E2E Path ADSPEC update
To comply with this specification, for the update of the E2E Path
ADSPEC, the same methods can be used as the ones described in
[RFC4860].
2.8. Intra-domain Routes
The PCN-interior-nodes are neither maintaining E2E RSVP nor RSVP
generic aggregation states and reservations. Therefore, intra-domain
route changes will not affect intra-domain reservations since such
reservations are not maintained by the PCN-interior-nodes.
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Furthermore, it is considered that by configuration, the PCN-
interior-nodes are not able to distinguish neither RSVP generic
aggregated sessions and their associated messages [RFC4860], nor E2E
RSVP sessions and their associated messages [RFC2205].
2.9. Inter-domain Routes
The PCN-charter scope precludes inter-domain considerations. However,
for solving inter-domain routes changes associated with the operation
of the RSVP messages, the same methods SHOULD be used as the ones
described in [RFC4860] and in Section 1.4.7 of
[RFC3175].
2.10. Reservations for Multicast Sessions
PCN does not consider reservations for multicast sessions.
2.11. Multi-level Aggregation
PCN does not consider multi-level aggregations within the PCN domain.
Therefore, the PCN-interior-nodes are not supporting multi-level
aggregation procedures. However, the Aggregator and Deaggregator
SHOULD support the multi-level aggregation procedures specified in
[RFC4860] and in Section 1.4.9 of [RFC3175].
2.12. Reliability Issues
To comply with this specification, for solving possible reliability
issues, the same methods MUST used as the ones described in Section 4
of [RFC4860].
3. Elements of Procedure
This section describes the procedures used to implement the
aggregated RSVP procedure over PCN. It is considered that the
procedures for aggregation of E2E reservations over generic aggregate
RSVP reservations are same as the procedures specified in Section
4 of [RFC4860] except where a departure from these procedures is
explicitly described in the present section. Please refer to
[RFC4860] for all the below error
cases:
o) Incomplete message
o) Unexpected objects
3.1. Receipt of E2E Path Message by Aggregating router
When the E2E Path message arrives at the exterior interface of the
Aggregator, (also PCN-ingress-node in this document), then standard
RSVP generic aggregation [RFC4860] procedures are used.
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3.2. Handling Of E2E Path Message by Interior Routers
The E2E Path messages traverse zero or more PCN-interior-nodes.
The PCN-interior-nodes receive the E2E Path message on an interior
interface and forward it on another interior interface.
It is considered that, by configuration, the PCN-interior-nodes
ignore the E2E RSVP signaling messages [RFC2205]. Therefore, the E2E
Path messages are simply forwarded as normal IP datagrams.
3.3. Receipt of E2E Path Message by Deaggregating router
When receiving the E2E Path message the Deaggregator (also PCN-
egress-node and Decision Point in this document) performs the
regular [RFC4860] procedures, augmented with the following rules:
o) The Deaggregator MUST NOT perform the RSVP-TTL vs IP TTL-
check and MUST NOT update the ADspec Break bit. This is because
the whole PCN-domain is effectively handled by E2E RSVP as a
virtual link on which integrated service is indeed supported
(and admission control performed) so that the Break bit MUST
NOT be set, see also [draft-lefaucheur-rsvp-ecn-01].
The Deaggregator forwards the E2E Path message towards the
receiver.
3.4. Initiation of new Aggregate Path Message by Aggregating Router
To comply with this specification, for the initiation of the new RSVP
generic aggregated Path message by the Aggregator (also PCN-ingress-
node in this document), the same methods MUST be used as the ones
described in [RFC4860].
3.5. Handling Of Aggregate Path Message By Interior Routers
The Aggregate Path messages traverse zero or more PCN-interior-nodes.
The PCN-interior-nodes receive the Aggregated Path message on an
interior interface and forward it on another interior interface.
It is considered that, by configuration, the PCN-interior-nodes
ignore the Aggregated Path signaling messages. Therefore, the
Aggregated Path messages are simply forwarded as normal IP datagrams.
3.6. Handling Of Aggregate Path Message By Deaggregating Router
When receiving the Aggregated Path message, the Deaggregator (also
PCN-egress-node and Decision Point in this document) performs the
regular [RFC4860] procedures, augmented with the following rules:
o) When the received Aggregated Path message by the Deaggregator
contains the RSVP-AGGREGATE-IPv4-PCN-response or
RSVP-AGGREGATE-IPv6-PCN-response PCN objects, which carry the
PCN-sent-rate, then the procedures specified in Section 3.18 of
this document MUST be followed.
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3.7. Handling of E2E Resv Message by Deaggregating Router
When the E2E Resv message arrives at the exterior interface of the
Deaggregator, (also PCN-egress-node and Decision Point in this
document) then standard RSVP aggregation [RFC4860] procedures are
used, augmented with the following rules:
o) The E2E RSVP session associated with an E2E Resv
message that arrives at the external interface of the Deaggregator
is mapped/matched with an RSVP generic aggregate and with a PCN
ingress-egress-aggregate.
o) Depending on the type of the PCN edge behavior supported by the
Deaggregator, the PCN admission control procedures specified in
Section 3.3.1 of [RFC6661] or [RFC6662] MUST be followed. Since no
admission control procedures over the RSVP aggregated reservations
in the PCN-core are required, unlike [RFC4860], the Deaggregator
does not perform any admission control of the E2E Reservation over
the mapped generic aggregate RSVP reservation. If the PCN based
admission control procedure is successful then the Deaggregator
MUST allow the new flow to be admitted onto the associated RSVP
generic aggregation reservation and onto the PCN ingress-egress-
aggregate, see [RFC6661] and [RFC6662]. If the PCN based admission
control procedure is not successful, then the E2E Resv MUST NOT be
admitted onto the associated RSVP generic aggregate reservation and
onto the PCN ingress-egress-aggregation. The E2E Resv message is
further processed according to [RFC4860].
The way of how the PCN-admission-state is maintained is specified in
[RFC6661] and [RFC6662].
3.8. Handling Of E2E Resv Message By Interior Routers
The E2E Resv messages traversing the PCN core are IP addressed to the
Aggregating router and are not marked with Router Alert, therefore
the E2E Resv messages are simply forwarded as normal IP datagrams.
3.9. Initiation of New Aggregate Resv Message By Deaggregating Router
To comply with this specification, for the initiation of the new RSVP
generic aggregated Resv message by the Deaggregator (also PCN-egress-
node and Decision Point in this document), the same methods MUST be
used as the ones described in
Section 4 of [RFC4860] augmented with the following rules:
o) The size of the generic aggregate reservation is irrelevant, see
Section 2.6, and can be set to any arbitrary value by the PCN-
egress node. The Deaggregator SHOULD set the value of a RSVP
generic aggregate reservation to a null bandwidth. We also
observe that there is no need for dynamic adjustment of the RSVP
generic aggregated reservation size.
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o) When [RFC6661] is used and the ETM-rate measured by the
Deaggregator contains a non-zero value for some
ingress-egress-aggregate, see [RFC6661] and [RFC6662], the
Deagregator MUST request the PCN-ingress-node to provide an
estimate of the rate (PCN-sent-rate) at which the Aggregator
(also PCN-ingress-node in this document) is receiving PCN-traffic
that is destined for the given ingress-egress-aggregate.
o) When [RFC6662] is used and the PCN-admission-state computed by the
Deaggregator, on the basis of the CLE is "block" for the given
ingress-egress-aggregate, the Deaggregator MUST request the PCN-
ingress-node to provide an estimate of the rate (PCN-sent-rate) at
which the Aggregator is receiving PCN-traffic that is
destined for the given ingress-egress-aggregate.
o) In the above two cases and when the PCN-sent-rate needs to be
requested from the Aggregator, the Deaggregator MUST generate
and send an (refresh) Aggregated Resv message to the Aggregator
that MUST carry one of the following PCN objects, see Section 4.1,
depending on whether IPv4 or IPv6 is supported:
o) RSVP-AGGREGATE-IPv4-PCN-request
o) RSVP-AGGREGATE-IPv6-PCN-request.
3.10. Handling of Aggregate Resv Message by Interior Routers
The Aggregated Resv messages traversing the PCN core are IP addressed
to the Aggregating router and are not marked with Router Alert,
therefore the Aggregated Resv messages are simply forwarded as normal
IP datagrams.
3.11. Handling of E2E Resv Message by Aggregating Router
When the E2E Resv message arrives at the interior interface of the
Aggregator (also PCN-ingress-node in this document), then standard
RSVP aggregation [RFC4860] procedures are used.
3.12. Handling of Aggregated Resv Message by Aggregating Router
When the Aggregated Resv message arrives at the interior interface of
the Aggregator, (also PCN-ingress-node in this document),
then standard RSVP aggregation [RFC4860] procedures are used,
augmented with the following rules:
o) the Aggregator SHOULD use the information carried by the PCN
objects, see Section 4, and follow the steps specified in
[RFC6661], [RFC6662]. If the "R" flag carried by the
RSVP-AGGREGATE-IPv4-PCN-request or RSVP-AGGREGATE-IPv6-PCN-request
PCN objects is set to ON, see Section 4.1, then the Aggregator
follows the steps described in Section 3.4 of [RFC6661] and
[RFC6662] on calculating the PCN-sent-rate. In particular, the
Aggregator MUST provide the estimated current rate of PCN-traffic
received at that node and destined for a given ingress-egress-
aggregate in octets per second (the PCN-sent-rate). The way this
rate estimate is derived is a matter of implementation, see
[RFC6661] or [RFC6662].
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o) the Aggregator initiates an Aggregated Path message. In
particular, when the Aggregator receives an Aggregated Resv
message which carries one of the following PCN objects:
RSVP-AGGREGATE-IPv4-PCN-request or RSVP-AGGREGATE-IPv6-PCN-
request, with the flag "R" set to ON, see Section 4.1, the
Aggregator initiates an Aggregated Path message, and includes the
calculated PCN-sent-rate into the RSVP-AGGREGATE-IPv4-PCN-response
or RSVP-AGGREGATE-IPv6-PCN-response PCN objects, see Section 4.1,
which that MUST be carried by the Aggregated Path message. This
Aggregated Path message is sent towards the Deaggregator (also
PCN-egress-node and Decision Point in this document) that
requested the calculation of the PCN-sent-rate.
3.13. Removal of E2E Reservation
To comply with this specification, for the removal of E2E
reservations, the same methods MUST be used as the ones described in
Section 4 of [RFC4860] and [RFC4495].
3.14. Removal of Aggregate Reservation
To comply with this specification, for the removal of RSVP generic
aggregated reservations, the same methods MUST be used as the ones
described in Section 4 of [RFC4860] and Section 2.10 of [RFC3175]. In
particular, should an aggregate reservation go away (presumably due
to a configuration change, route change, or policy event), the E2E
reservations it supports are no longer active.
They MUST be treated accordingly.
3.15. Handling of Data On Reserved E2E Flow by Aggregating Router
The handling of data on the reserved E2E flow by Aggregator (also
PCN-ingress-node in this document) uses the procedures described
in [RFC4860] augmented with:
o) Regarding, PCN marking and traffic classification the procedures
defined in Section 2.2 and 2.3 of this document are used.
3.16. Procedures for Multicast Sessions
In this document no multicast sessions are considered.
3.17. Misconfiguration of PCN-node
In an event where a PCN-node is misconfigured within a PCN-domain,
the desired behavior is same as described in Section 3.10.
3.18 PCN based Flow Termination
When the Deaggregator (also PCN-egress-node and Decision Point in
this document) needs to terminate an amount of traffic associated
with one ingress-egress-aggregate (see Section 3.3.2 of [RFC6661] and
[RFC6662]), then several procedures of terminating E2E microflows can
be deployed. The default procedure of terminating E2E microflows
(i.e., PCN-flows) is as follows, see i.e., [RFC6661] and [RFC6662].
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For the same ingress-egress-aggregate, select a number of E2E
microflows to be terminated in order to decrease the total incoming
amount of bandwidth associated with one ingress-egress-aggregate by
the amount of traffic to be terminated, see above. In this situation
the same mechanisms for terminating an E2E microflow can be followed
as specified in [RFC2205]. However, based on a local policy, the
Deaggregator could use other ways of selecting which microflows
should be terminated. For example, for the same ingress-egress-
aggregate, select a number of E2E microflows to be terminated or to
reduce their reserved bandwidth in order to decrease the total
incoming amount of bandwidth associated with one ingress-egress-
aggregate by the amount of traffic to be terminated. In this
situation the same mechanisms for terminating an E2E microflow or
reducing bandwidth associated with an E2E microflow can be followed
as specified in [RFC4495].
4. Protocol Elements
The protocol elements in this document are using the ones defined in
Section 4 of [RFC4860] and Section 3 of [RFC3175] augmented with the
following rules:
o) the DSCP value included in the SESSION object, SHOULD be set equal
to a PCN-compatible Diffserv codepoint.
o) Extended vDstPort SHOULD be set to the IPv4 or IPv6 destination
addresses, of the Aggregator (also PCN-ingress-node in this
document), see [RFC4860].
o) When the Deaggregator (also PCN-egress-node and Decision Point
in this document) needs to request the PCN-sent-rate from the
PCN-ingress-node, see Section 3.9 of this document, the
Deaggregator MUST generate and send an (refresh) Aggregate
Resv message to the Aggregator that MUST carry one of the
following PCN objects, see Section 4.1, depending on whether IPv4
or IPv6 is supported:
o) RSVP-AGGREGATE-IPv4-PCN-request
o) RSVP-AGGREGATE-IPv6-PCN-request.
o) When the Aggregator receives an Aggregate Resv message which
carries one of the following PCN objects:
RSVP-AGGREGATE-IPv4-PCN-request or
RSVP-AGGREGATE-IPv6-PCN-request, with the flag "R" set to ON, see
Section 4.1, then the Aggregator MUST generate and send to the
Deaggregator an Aggregated Path message which carries one of the
following PCN objects, see Section 4.1, depending on whether IPv4
or IPv6 is supported:
o) RSVP-AGGREGATE-IPv4-PCN-response,
o) RSVP-AGGREGATE-IPv6-PCN-response.
4.1 PCN objects
This section describes four types of PCN objects that can be carried
by the (refresh) Aggregate Path or the (refresh) Aggregate Resv
messages specified in [RFC4860].
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These objects are:
o RSVP-AGGREGATE-IPv4-PCN-request,
o RSVP-AGGREGATE-IPv6-PCN-request,
o RSVP-AGGREGATE-IPv4-PCN-response,
o RSVP-AGGREGATE-IPv6-PCN-response.
o) RSVP-AGGREGATE-IPv4-PCN-request: PCN request object, when
IPv4 addresses are used:
Class = 248 (PCN)
C-Type = 1 (RSVP-AGGREGATE-IPv4-PCN-request
+-------------+-------------+-------------+-------------+
| IPv4 PCN-ingress-node Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| IPv4 PCN-egress-node Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| IPv4 Decision Point Address (4 bytes) |
+-------------+-------------+-------------+-------------+
|R| Reserved |
+-------------+-------------+-------------+-------------|
o) RSVP-AGGREGATE-IPv6-PCN-request: PCN object, when
IPv6 addresses are used:
Class = 248 (PCN)
C-Type = 2 (RSVP-AGGREGATE-IPv6-PCN-request
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ IPv6 PCN-ingress-node Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ IPv6 PCN-egress-node Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ Decision Point Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
|R| Reserved |
+-------------+-------------+-------------+-------------+
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o) RSVP-AGGREGATE-IPv4-PCN-response: PCN object, IPv4
addresses are used:
Class = 248 (PCN)
C-Type = 3 (RSVP-AGGREGATE-IPv4-PCN-response)
+-------------+-------------+-------------+-------------+
| IPv4 PCN-ingress-node Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| IPv4 PCN-egress-node Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| IPv4 Decision Point Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| PCN-sent-rate |
+-------------+-------------+-------------+-------------+
o) RSVP-AGGREGATE-IPv6-PCN-response: PCN object, IPv6
addresses are used:
Class = 248 (PCN)
C-Type = 4 (RSVP-AGGREGATE-IPv6-PCN-response)
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ IPv6 PCN-ingress-node Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ IPv6 PCN-egress-node Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ Decision Point Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| PCN-sent-rate |
+-------------+-------------+-------------+-------------+
The fields carried by the PCN object are specified in
[RFC6663], [RFC6661] and [RFC6662]:
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o the IPv4 or IPv6 address of the PCN-ingress-node (Aggregator) and
the IPv4 or IPv6 address of the PCN-egress-node (Deaggregator);
together they specify the ingress-egress-aggregate to which the
report refers. According to [RFC6663] the report should carry the
identifier of the PCN-ingress-node (Aggregator) and the
identifier of the PCN-egress-node (Deaggregator) (typically
their IP addresses);
o Decision Point address specify the IPv4 or IPv6 address of the
Decision Point. In this document this field MUST contain the IP
address of the Deaggregator.
o "R": 1 bit flag that when set to ON, signifies, according to
[RFC6661] and [RFC6662], that the PCN-ingress-node (Aggregator)
MUST provide an estimate of the rate (PCN-sent-rate) at which the
PCN-ingress-node (Aggregator) is receiving PCN-traffic that is
destined for the given ingress-egress-aggregate.
O "Reserved": 31 bits that are currently not used by this
document and are reserved. These SHALL be set to 0 and SHALL be
ignored on reception.
o PCN-sent-rate: the PCN-sent-rate for the given
ingress-egress-aggregate. It is expressed in octets/second; its
format is a 32-bit IEEE floating point number; The PCN-sent-rate
is specified in [RFC6661] and [RFC6662] and it represents the
estimate of the rate at which the PCN-ingress-node (Aggregator)
is receiving PCN-traffic that is destined for the given
ingress-egress-aggregate.
5. Security Considerations
The security considerations specified in [RFC2205], [RFC4860] and
[RFC5559] apply to this document. In addition, [RFC4230] and
[RFC6411] provide useful guidance on RSVP security mechanisms.
Security within a PCN domain is fundamentally based on the controlled
environment trust assumption stated in Section 6.3.1 of [RFC5559], in
particular that all PCN-nodes are PCN-enabled and are trusted
to perform accurate PCN-metering and PCN-marking.
In the PCN domain environments addressed by this document, Generic
Aggregate Resource ReSerVation Protocol (RSVP) messages specified in
[RFC4860] are used for support of the PCN Controlled Load (CL) and
Single Marking (SM) edge behaviors over a Diffserv cloud using Pre-
Congestion Notification. Hence the security mechanisms discussed
in [RFC4860] are applicable. Specifically, the INTEGRITY object
[RFC2747][RFC3097] can be used to provide hop-by-hop RSVP message
integrity, node authentication and replay protection, thereby
protecting against corruption and spoofing of RSVP messages and
PCN feedback conveyed by RSVP messages.
For these reasons, this document does not introduce significant
additional security considerations beyond those discussed in
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[RFC5559] and [RFC4860].
6. IANA Considerations
IANA has modified the RSVP parameters registry, 'Class Names,
Class Numbers, and Class Types' subregistry, to add a new
Class Number and assign 4 new C-Types under this new Class
Number, as described below, see Section 4.1:
Class
Number Class Name Reference
------ ---------------------- ---------
248 PCN this document
Class Types or C-Types:
1 RSVP-AGGREGATE-IPv4-PCN-request this document
2 RSVP-AGGREGATE-IPv6-PCN-request this document
3 RSVP-AGGREGATE-IPv4-PCN-response this document
4 RSVP-AGGREGATE-IPv6-PCN-response this document
When this draft is published as an RFC, IANA should update the
reference for the above 5 items to that published RFC (and the RFC
Editor should remove this sentence).
7. Acknowledgments
We would like to thank the authors of [draft-lefaucheur-rsvp-ecn-
01.txt], since some ideas used in this document are based on the work
initiated in [draft-lefaucheur-rsvp-ecn-01.txt]. Moreover, we would
like to thank Bob Briscoe, David Black, Ken Carlberg, Tom Taylor,
Philip Eardley, Michael Menth, Toby Moncaster, James Polk, Scott
Bradner, Lixia Zhang and Robert Sparks for the provided comments. In
particular, we would like to thank Francois Le Faucheur for
contributing in addition to comments also to a significant amount of
text.
8. Normative References
[RFC6661] T. Taylor, A, Charny, F. Huang,
G. Karagiannis, M. Menth, "PCN Boundary Node Behaviour for the
Controlled Load (CL) Mode of Operation", July
2012.
[RFC6662] A. Charny, J. Zhang,
G. Karagiannis, M. Menth, T. Taylor, "PCN Boundary Node Behaviour
for the Single Marking (SM) Mode of Operation",
July 2012.
[RFC6663] G. Karagiannis, T. Taylor,
K. Chan, M. Menth, P. Eardley, " Requirements for Signaling of (Pre-)
Congestion Information in a DiffServ Domain",
July 2012.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2205] Braden, R., ed., et al., "Resource ReSerVation Protocol
(RSVP)- Functional Specification", RFC 2205, September 1997.
[RFC3140] Black, D., Brim, S., Carpenter, B., and F. Le
Faucheur, "Per Hop Behavior Identification Codes",
RFC 3140, June 2001.
[RFC3175] Baker, F., Iturralde, C., Le Faucheur, F., and B. Davie,
"Aggregation of RSVP for IPv4 and IPv6 Reservations", RFC 3175,
September 2001.
[RFC4495] Polk, J. and S. Dhesikan, "A Resource Reservation
Protocol (RSVP) Extension for the Reduction of
Bandwidth of a Reservation Flow", RFC 4495, May 2006.
[RFC4860] F. Le Faucheur, B. Davie, P. Bose, C. Christou, M.
Davenport, "Generic Aggregate Resource ReSerVation Protocol (RSVP)
Reservations", RFC4860, May 2007.
[RFC5670] Eardley, P., "Metering and Marking Behaviour of PCN-Nodes",
RFC 5670, November 2009.
[RFC6660] Moncaster, T., Briscoe, B., and M. Menth, "Baseline
Encoding and Transport of Pre-Congestion Information", RFC 6660,
July 2012.
9. Informative References
[draft-lefaucheur-rsvp-ecn-01.txt] Le Faucheur, F., Charny, A.,
Briscoe, B., Eardley, P., Chan, K., and J. Babiarz, "RSVP Extensions
for Admission Control over Diffserv using Pre-congestion
Notification (PCN) (Work in progress)", June 2006.
[RFC1633] Braden, R., Clark, D., and S. Shenker, "Integrated
Services in the Internet Architecture: an Overview", RFC 1633, June
1994.
[RFC2211] J. Wroclawski, Specification of the Controlled-Load Network
Element Service, September 1997
[RFC2212] S. Shenker et al., Specification of Guaranteed Quality of
Service, September 1997
[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.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z. and
W. Weiss, "A framework for Differentiated Services", RFC 2475,
December 1998.
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[RFC2747] Baker, F., Lindell, B., and M. Talwar, "RSVP Cryptographic
Authentication", RFC 2747, January 2000.
[RFC2753] Yavatkar, R., D. Pendarakis and R. Guerin, "A Framework for
Policy-based Admission Control", January 2000.
[RFC2998] Bernet, Y., Yavatkar, R., Ford, P., Baker, F., Zhang, L.,
Speer, M., Braden, R., Davie, B., Wroclawski, J. and E. Felstaine, "A
Framework for Integrated Services Operation Over DiffServ Networks",
RFC 2998, November 2000.
[RFC3097] Braden, R. and L. Zhang, "RSVP Cryptographic Authentication
-- Updated Message Type Value", RFC 3097, April 2001.
[RFC4230] H. Tschofenig, R. Graveman, "RSVP Security Properties",
RFC 4230, December 2005.
[RFC5559] Eardley, P., "Pre-Congestion Notification (PCN)
Architecture", RFC 5559, June 2009.
[RFC6411] M. Behringer, F. Le Faucheur, B. Weis, "Applicability of
Keying Methods for RSVP Security", RFC 6411, October 2011.
[SIG-NESTED] Baker, F. and P. Bose, "QoS Signaling in a Nested
Virtual Private Network", Work in Progress, July 2007.
10. Appendix A: Example Signaling Flow
This appendix is based on the appendix provided in [RFC4860]. In
particular, it provides an example signaling flow of the
specification detailed in Section 3 and 4.
This signaling flow assumes an environment where E2E reservations are
aggregated over generic aggregate RSVP reservations and applied over
a PCN domain. In particular the Aggregator (PCN-ingress-node) and
Deaggregator (PCN-egress-node) are located at the boundaries of the
PCN domain. The PCN-interior-nodes are located within the PCN-domain,
between the PCN-boundary nodes, but are not shown in this Figure. It
illustrates a possible RSVP message flow that could take place in the
successful establishment of a unicast E2E reservation that is the
first between a given pair of Aggregator/Deaggregator.
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Aggregator (PCN-ingress-node) Deaggregator (PCN-egress-node)
E2E Path
----------->
(1)
E2E Path
------------------------------->
(2)
E2E PathErr(New-agg-needed,SOI=GApcn)
<----------------------------------
(3)
AggPath(Session=GApcn)
------------------------------->
(4)
E2E Path
----------->
(5)
AggResv (Session=GApcn) (PCN object)
<-------------------------------
(6)
AggResvConfirm (Session=GApcn)
------------------------------>
(7)
E2E Resv
<---------
(8)
E2E Resv (SOI=GApcn)
<-----------------------------
(9)
E2E Resv
<-----------
(1) The Aggregator forwards E2E Path into the aggregation region
after modifying its IP protocol number to RSVP-E2E-IGNORE
(2) Let's assume no Aggregate Path exists. To be able to accurately
update the ADSPEC of the E2E Path, the Deaggregator needs the
ADSPEC of Aggregate Path. In this example, the Deaggregator
elects to instruct the Aggregator to set up an Aggregate Path
state for the PCN PHB-ID. To do that, the Deaggregator
sends an E2E PathErr message with a New-Agg-Needed PathErr
code.
The PathErr message also contains a SESSION-OF-INTEREST
(SOI) object. The SOI contains a GENERIC-AGGREGATE SESSION
(GApcn) whose PHB-ID is set to the PCN PHB-ID. The GENERIC-
AGGREGATE SESSION contains an interface-independent Deaggregator
address inside the DestAddress and appropriate values inside the
vDstPort and Extended vDstPort fields. In this document, the
Extended vDstPort SHOULD contain the IPv4 or IPv6 address of
the Aggregator.
(3) The Aggregator follows the request from the Deaggregator and
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signals an Aggregate Path for the GENERIC-AGGREGATE Session
(GApcn).
(4) The Deaggregator takes into account the information contained in
the ADSPEC from both Aggregate Paths and updates the E2E Path
ADSPEC accordingly. The PCN-egress-node MUST NOT perform the
RSVP-TTL vs IP TTL-check and MUST NOT update the ADspec Break
bit. This is because the whole PCN-domain is effectively handled
by E2E RSVP as a virtual link on which integrated service is
indeed supported (and admission control performed) so that the
Break bit MUST NOT be set, see also
[draft-lefaucheur-rsvp-ecn-01]. The Deaggregator also modifies
the E2E Path IP protocol number to RSVP before forwarding it.
(5) In this example, the Deaggregator elects to immediately proceed
with establishment of the generic aggregate reservation. In
effect, the Deaggregator can be seen as anticipating
the actual demand of E2E reservations so that the generic
aggregate reservation is in place when the E2E Resv
request arrives, in order to speed up establishment of E2E
reservations. Here it is also assumed that the Deaggregator
includes the optional Resv Confirm Request in the Aggregate
Resv message.
(6) The Aggregator merely complies with the received ResvConfirm
Request and returns the corresponding Aggregate ResvConfirm.
(7) The Deaggregator has explicit confirmation that the generic
aggregate reservation is established.
(8) On receipt of the E2E Resv, the Deaggregator applies the mapping
policy defined by the network administrator to map the E2E Resv
onto a generic aggregate reservation. Let's assume that this
policy is such that the E2E reservation is to be mapped onto the
generic aggregate reservation with the PCN PHB-ID=x. The
Deaggregator knows that a generic aggregate reservation (GApcn)
is in place for the corresponding PHB-ID since (7). At this step
the Deaggregator maps the generic aggregated reservation onto one
ingress-egress-aggregate maintained by the Deaggregator (as a
PCN-egress-node), see Section 3.7. The Deaggregator performs
admission control of the E2E Resv onto the generic Aggregate
reservation for the PCN PHB-ID (GApcn). The Deaggregator takes
also into account the PCN admission control procedure as
as specified in [RFC6661] and [RFC6662], see Section 3.7.
If one or both the admission control procedures (PCN based
admission control procedure and admission control procedure
specified in [RFC4860]) are not successful, then the E2E Resv is
not admitted onto the associated RSVP generic aggregate
reservation for the PCN PHB-ID (GApcn). Otherwise, assuming that
the generic aggregate reservation for the PCN (GApcn) had been
established with sufficient bandwidth to support the E2E Resv,
the Deaggregator adjusts its counter, tracking the unused
bandwidth on the generic aggregate reservation. Then it forwards
the E2E Resv to the Aggregator including a SESSION-OF-INTEREST
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object conveying the selected mapping onto GApcn (and hence onto
the PCN PHB-ID).
(9) The Aggregator records the mapping of the E2E Resv onto GApcn
(and onto the PCN PHB-ID). The Aggregator removes the SOI object
and forwards the E2E Resv towards the sender.
11. Authors' Address
Georgios Karagiannis
Huawei Technologies
Hansaallee 205,
40549 Dusseldorf,
Germany
Email: Georgios.Karagiannis@huawei.com
Anurag Bhargava
Cisco Systems, Inc.
7100-9 Kit Creek Road
PO Box 14987
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27709-4987
USA
Email: anuragb@cisco.com
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