CCAMP Working Group Zafar Ali
Reshad Rahman
Danny Prairie
Cisco Systems, Inc. Systems
D. Papadimitriou
Alcatel
Internet Draft
Category: Informational BCP
Expires: August October 2004 February April 2004
Node ID based RSVP Hello: A Clarification Statement
draft-ali-ccamp-rsvp-node-id-based-hello-00.txt
draft-ali-ccamp-rsvp-node-id-based-hello-01.txt
Status of this Memo
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Abstract
Use of node-id based RSVP Hello messages is implied in a number of
cases, e.g., when data and control plan are separated, when TE links
are unnumbered. Furthermore, when link level failure detection is
performed by some means other than RSVP Hellos, use of node-id based
Hellos is optimal for node detecting signaling adjacency failure detection. for RSVP-
TE. Nonetheless, this implied behavior is unclear and this informational draft clarifies document
formalizes use of node-id based RSVP Hellos. Hello sessions as a best current
practice (BCP) in some scenarios.
Z. Ali, et al. Page 1 4/16/2004
Conventions used in this document
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].
Routing Area ID Summary
(This section to be removed before publication.)
SUMMARY
This draft document clarifies use of node-id based RSVP Hellos.
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WHERE DOES IT FIT IN THE PICTURE OF THE ROUTING AREA WORK?
This work fits in the context of [RFC 3209] and [RFC 3473].
WHY IS IT TARGETED AT THIS WG?
This draft document is targeted at ccamp as it clarifies procedures in
[RFC 3209] and [RFC 3473], related to use of RSVP-TE Hello protocol.
RELATED REFERENCES
Please refer to the reference section.
Table of Contents
1. Terminology....................................................2
2. Introduction...................................................2 Introduction...................................................3
3. Node-id based RSVP Hellos......................................3
4. Backward Compatibility Note....................................4
5. Security Considerations........................................4
6. Acknowledgements...............................................4
7. IANA Considerations............................................4
Reference.........................................................4 Considerations............................................5
8. Reference......................................................5
8.1 Normative Reference........................................5
8.2 Informative Reference......................................5
9. Author's Addresses................................................4 Addresses.............................................5
1. Terminology
Node-id: Router-id as defined advertised in the Router Address TLV for OSPF
[OSPF-TE] and Traffic Engineering router ID TLV for ISIS [ISIS-TE].
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Node-id based Hello Session: A Hello session such that local and
remote node-ids are used in the source and destination fields of the
Hello packet, respectively.
Interface bounded Hello Session: A Hello session such that local and
remote addresses of the interface in question are used in the source
and destination fields of the Hello packet, respectively.
2. Introduction
The RSVP Hello protocol message exchange was introduced in [RFC 3209]. The
usage of RSVP Hello protocol is over-loaded has been extended in [RFC 3473] to support RSVP
Graceful Restart (GR) procedures. Specifically, [RFC 3473] specifies
the use of the RSVP Hello protocol Hellos for GR procedures for Generalized MPLS
(GMPLS). GMPLS introduces the notion of control plane and data plane
separation. In other words, in GMPLS networks, the control plane
information is carried over a control network, network whose end-points are IP
capable, and which may be physically different than or logically disjoint from the
data network. The notion of separation
of data and control plane also applies to the Optical User Network
Interface (O-UNI) 1.0 Signaling Specification [OIF-UNI], which reuses
the RSVP GR procedures defined in [RFC 3473]. bearer links it controls. One of the consequences of separation
of data bearer links from control channels is that RSVP Hellos are
not exchanged over terminated on data links; instead bearer linksÆ interfaces even if (some of)
those are numbered. Instead RSVP hellos use are terminated at the control channel.
channel (IP-capable) end-points. The latter MAY be identified by the
value assigned to the node hosting these control channels i.e. Node-
Id. Consequently, the use of RSVP Hellos for GR applications
introduces a need for clarifying the behavior and usage of node-id
based Hellos. Nonetheless,
this implied behavior is unclear and this draft clarifies
Even in the usage.
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Another scenario which introduces case of packet MPLS, when link failure detection is
performed by some means other than RSVP Hellos (e.g., [BFD]), the need for use
of node-id based Hellos is when nodes support unnumbered TE links. Specifically, also optimal for detection of signaling
adjacency failures for RSVP-TE. Similarly, when all TE links between
neighbor nodes are unnumbered, it is implied that the nodes will use
node-id based Hellos for detecting node detection of signaling adjacency failures.
This
draft document also clarifies the use of node-id based Hellos when all
or a sub-set of TE links are unnumbered.
When link level failure detection is performed by some means other
than RSVP Hellos (e.g., [BFD]), the This draft also clarifies
use of node-id based Hellos is
also optimal for detection of nodal failures. in these scenarios.
3. Node-id based RSVP Hellos
A node-id based Hello session is established through the exchange of
RSVP Hello messages such that local and remote node-ids are
respectively used in the source and destination fields of Hello
packets. Here, node-id refers to a router-id as defined in the Router
Address TLV for OSPF [OSPF-TE] and the Traffic Engineering router ID
TLV for ISIS [ISIS-TE]. This section formalizes a procedure for
establishing node-id based Hello sessions.
Z. Ali, et al. Page 3 4/16/2004
If a node wishes to establish a node-id based RSVP Hello session with
its neighbor, it sends a Hello Request message with its node-id in the source
IP address field of the Hello packet. Furthermore, the node also puts
the neighborÆs node-id in the destination address field of the IP
packet.
An implementation may initiate a node-id based Hello session when it
starts sharing RSVP states with the neighbor or at an earlier time.
Similarly, an implementation may use the IGP topology to determine
the remote node-id which matches an interface address(es) used in
RSVP signaling. These aspects are considered to be a local
implementation decision.
When a node receives a Hello packet where the destination IP address
is its local node-id as advertised in the IGP-TE topology, the node
MUST use its node-id in replying to the Hello message. In other
words, nodes must ensure that the node-ids used in RSVP Hello
messages are those derived/contained in the IGP-TE topology.
Furthermore, a node can only run one node-id based RSVP Hello session
per IGP instance (i.e., per node-id pair) with its neighbor.
If all interfaces between a pair of nodes are unnumbered,
In the optimal
way to use RSVP to detect nodal failure is to run node-id based
Hellos. Similarly, case of packet MPLS, when link level failure detection is performed
by some means other than RSVP Hellos, use of node-id based Hellos is
also optimal in detecting nodal failures. Therefore, signaling adjacency failures, e.g., for
RSVP GR procedure. Similarly, if all interfaces between a pair of
nodes are unnumbered unnumbered, the optimal way to use RSVP to detect signaling
adjacency failure is to run node-id based Hellos. Furthermore, in the
case of optical network with single or multiple, numbered or
unnumbered control channels, use of node-id based Hellos for
detecting signaling adjacency failure is also optimal. Therefore,
when link level failure detection is performed by some means other than
RSVP Hellos, or if all interfaces between a pair of nodes are
unnumbered, or in GMPLS network with data and control plane
separation, a node MUST run node-id based Hellos for node detection of
signaling adjacency failure detection. for RSVP-TE. Nonetheless, if it is
desirable to distinguish between node signaling adjacency and link
failures, node id based Hellos can co-exist with interface bound
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draft-ali-ccamp-rsvp-node-id-based-hello-00.txt February 2004
Hellos.
Hellos messages. Similarly, if a pair of nodes share numbered and
unnumbered TE links, node id and interface based Hellos can co-exist.
4. Backward Compatibility Note
The procedure presented in this draft document is backward compatible with
both [RFC3209] and [RFC3473].
5. Security Considerations
This document does not introduce new security issues. The security
considerations pertaining to the original RSVP protocol [RFC2205] [RFC3209] remain relevant.
6. Acknowledgements
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We would like to thank Anca Zamfir, Jean-Louis Le Roux, Arthi
Ayyangar and Carol Iturralde for their useful comments and
suggestions.
7. IANA Considerations
None.
8. Reference
8.1 Normative Reference
[RFC2205] " Resource "Resource ReSerVation Protocol (RSVP) - Version 1,
Functional Specification", RFC 2205, Braden, et al, September
1997.
[RFC3209] "Extensions to RSVP for LSP Tunnels", D. Awduche, et al,
RFC 3209, December 2001.
[RFC3471] Generalized Multi-Protocol Label Switching (GMPLS)
Signaling Functional Description, RFC 3471, L. Berger, et al,
January 2003.
[RFC3473] "Generalized Multi-Protocol Label Switching (GMPLS)
Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-
TE) Extensions", RFC 3471, 3473, L. Berger, et al, January 2003.
[RFC2119] "Key words for use in RFCs to Indicate Requirement Levels",
RFC 2119, S. Bradner, March 1997.
[OIF-UNI] "User Network Interface (UNI) 1.0 Signaling Specification -
Implementation Agreement OIF-UNI-01.0," The Optical Internetworking
Forum, October 2001.
8.2 Informative Reference
[OSPF-TE] Katz, D., Yeung, D., Kompella, K., "Traffic Engineering
Extensions to OSPF Version 2", draft-katz-yeung-ospf-traffic-
09.txt(work in progress). RFC 3630.
[ISIS-TE] Li, T., Smit, H., "IS-IS extensions for Traffic
Engineering", draft-ietf-isis-traffic-04.txt draft-ietf-isis-traffic-05.txt (work in progress) progress).
[BFD] Katz, D., and Ward, D., "Bidirectional Forwarding Detection",
draft-katz-ward-bfd-01.txt (work in progress).
9. Author's Addresses
Zafar Ali
Cisco Systems Inc.
Z. Ali, et al. Page 4 2/5/2004
100 South Main St. #200
Ann Arbor, MI 48104, USA.
Z. Ali, et al. Page 5 4/16/2004
Phone: (734) 276-2459
Email: zali@cisco.com
Reshad Rahman
Cisco Systems Inc.
2000 Innovation Dr.,
Kanata, Ontario, K2K 3E8, Canada.
Phone: (613)-254-3519
Email: rrahman@cisco.com dprairie@cisco.com
Danny Prairie
Cisco Systems Inc.
2000 Innovation Dr.,
Kanata, Ontario, K2K 3E8, Canada.
Phone: (613)-254-3519
Email: dprairie@cisco.com rrahman@cisco.com
Dimitri Papadimitriou (Alcatel)
Fr. Wellesplein 1,
B-2018 Antwerpen, Belgium
Phone: +32 3 240-8491
Email: dimitri.papadimitriou@alcatel.be
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