GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc4558

Network Working Group Z. Ali Request for Comments: 4558 R. Rahman Category: Standards Track D. Prairie

                                                         Cisco Systems
                                                      D. Papadimitriou
                                                               Alcatel
                                                             June 2006
     Node-ID Based Resource Reservation Protocol (RSVP) Hello:
                     A Clarification Statement

Status of This Memo

 This document specifies an Internet standards track protocol for the
 Internet community, and requests discussion and suggestions for
 improvements.  Please refer to the current edition of the "Internet
 Official Protocol Standards" (STD 1) for the standardization state
 and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

 Copyright (C) The Internet Society (2006).

Abstract

 Use of Node-ID based Resource Reservation Protocol (RSVP) Hello
 messages is implied in a number of cases, e.g., when data and control
 planes are separated, when TE links are unnumbered.  Furthermore,
 when link level failure detection is performed by some means other
 than exchanging RSVP Hello messages, use of a Node-ID based Hello
 session is optimal for detecting signaling adjacency failure for
 Resource reSerVation Protocol-Traffic Engineering (RSVP-TE).
 Nonetheless, this implied behavior is unclear, and this document
 formalizes use of the Node-ID based RSVP Hello session in some
 scenarios.  The procedure described in this document applies to both
 Multi-Protocol Label Switching (MPLS) and Generalized MPLS (GMPLS)
 capable nodes.

Ali, et al. Standards Track [Page 1] RFC 4558 Node-ID Based RSVP Hello June 2006

1. Introduction

 The RSVP Hello message exchange was introduced in [RFC3209].  The
 usage of RSVP Hello has been extended in [RFC3473] to support RSVP
 Graceful Restart (GR) procedures.
 More specifically, [RFC3473] specifies the use of the RSVP Hello
 messages 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 whose end-points are IP capable and
 that may be physically or logically disjoint from the data bearer
 links it controls.  One of the consequences of separation of data
 bearer links from control channels is that RSVP Hello messages are
 not terminated on data bearer links' interfaces even if (some of)
 those are numbered.  Instead, RSVP Hello messages are terminated at
 the control 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 Hello
 messages for GR applications introduces a need for clarifying the
 behavior and usage of Node-ID based Hello sessions.
 Even in the case of packet switching capable interfaces, when link
 failure detection is performed by some means other than RSVP Hello
 messages (e.g., [BFD]), the use of Node-ID based Hello sessions is
 also optimal for detection of signaling adjacency failures for
 GMPLS-RSVP-TE and RSVP-TE when there is more than one link between a
 pair of nodes.  Similarly, when all TE links between neighbor nodes
 are unnumbered, it is implied that the nodes will exchange Node-ID
 based Hello messages for detection of signaling adjacency failures.
 This document also clarifies the use of Node-ID based Hello message
 exchanges when all or a sub-set of TE links are unnumbered.

2. Terminology

 Node-ID: TE Router ID as advertised in the Router Address TLV for
 OSPF [OSPF-TE] and Traffic Engineering Router ID TLV for ISIS
 [ISIS-TE].  For IPv6, the Node-ID refers to the Router_IPv6_Address
 for OSPFv3 [OSPFv3-TE] and the IPv6 TE Router_ID for IS-IS
 [IS-ISv6-TE].
 Node-ID based Hello Session: A Hello session in which 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 in which local and
 remote addresses of the interface in question are used in the source
 and destination fields of the Hello packet, respectively.

Ali, et al. Standards Track [Page 2] RFC 4558 Node-ID Based RSVP Hello June 2006

2.1. 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].

3. Node-ID Based RSVP Hello Messages

 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, for IPv4, Node-ID refers to the TE router-id as
 defined in the Router Address TLV for OSPF [OSPF-TE] and the Traffic
 Engineering router ID TLV for ISIS [ISIS-TE].  For IPv6, the Node-ID
 refers to the Router_IPv6_Address for OSPFv3 [OSPFv3-TE] and the IPv6
 TE Router_ID for IS-IS [IS-ISv6-TE].  This section formalizes a
 procedure for establishing Node-ID based Hello sessions.
 If a node wishes to establish a Node-ID based RSVP Hello session with
 its neighbor, it sends a Hello message with its Node-ID in the source
 IP address field of the Hello packet.  Furthermore, the node also
 puts the neighbor's Node-ID in the destination address field of the
 IP packet.
 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.
 Even in the case of packet switching capable interfaces, when link
 failure detection is performed by some means other than exchanging
 RSVP Hello messages, use of Node-ID based Hello sessions is also
 optimal in detecting signaling adjacency failures for GMPLS-RSVP-TE
 and RSVP-TE when there is more than one link between a pair of nodes.
 Similarly, if all interfaces between a pair of nodes are unnumbered,
 the optimal way to use RSVP to detect signaling adjacency failure is
 to run Node-ID based Hello sessions.  Furthermore, in the case of an
 optical network with single or multiple numbered or unnumbered
 control channels, use of Node-ID based Hello messages for detecting
 signaling adjacency failure is also optimal.  Therefore, when link
 failure detection is performed by some means other than exchanging
 RSVP Hello messages, or if all interfaces between a pair of nodes are
 unnumbered, or in a GMPLS network with data and control plane
 separation, a node MUST run Node-ID based Hello sessions for
 detection of signaling adjacency failure for RSVP-TE.  Nonetheless,

Ali, et al. Standards Track [Page 3] RFC 4558 Node-ID Based RSVP Hello June 2006

 if it is desirable to distinguish between signaling adjacency and
 link failures, Node-ID based Hello sessions can co-exist with the
 exchange of interface bound Hellos messages.  Similarly, if a pair of
 nodes share numbered and unnumbered TE links, Node-ID and interface
 based Hello sessions can co-exist.

4. Backward Compatibility Note

 The procedure presented in this document is backward compatible with
 both [RFC3209] and [RFC3473].
 Per [RFC3209], the Hello mechanism is intended for use between
 immediate neighbors, and Hello messages are by default sent between
 direct RSVP neighbors.  This document does not modify this behavior,
 as it uses as "local node_id" the IPv4/IPv6 source address of the
 sending node and as "remote node_id" the IPv4/IPv6 destination
 address of the neighbor node.  TTL/Hop Limit setting and processing
 are also left unchanged.
 Moreover, this document does not modify the use of Hello Processing
 for State Recovery as defined in Section 9.3 of [RFC3473] (including
 definition and processing of the RESTART_CAP object).

5. Security Considerations

 As this document does not modify or extend the RSVP Hello messages
 exchange between immediate RSVP neighbors, it does not introduce new
 security considerations.
 The security considerations pertaining to the original [RFC3209]
 remain relevant.  RSVP message security is described in [RFC2747] and
 provides Hello message integrity and authentication of the Node-ID
 ownership.

6. Acknowledgements

 We would like to thank Anca Zamfir, Jean-Louis Le Roux, Arthi
 Ayyangar, and Carol Iturralde for their useful comments and
 suggestions.

Ali, et al. Standards Track [Page 4] RFC 4558 Node-ID Based RSVP Hello June 2006

7. Reference

7.1. Normative References

 [RFC2119]    Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.
 [RFC2747]    Baker, F., Lindell, B., and M. Talwar, "RSVP
              Cryptographic Authentication", RFC 2747, January 2000.
 [RFC3209]    Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan,
              V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
              Tunnels", RFC 3209, December 2001.
 [RFC3473]    Berger, L., "Generalized Multi-Protocol Label Switching
              (GMPLS) Signaling Resource ReserVation Protocol-Traffic
              Engineering (RSVP-TE) Extensions", RFC 3473, January
              2003.

7.2. Informative References

 [OSPF-TE]    Katz, D., Kompella, K., and D. Yeung, "Traffic
              Engineering (TE) Extensions to OSPF Version 2", RFC
              3630, September 2003.
 [ISIS-TE]    Smit, H. and T. Li, "Intermediate System to Intermediate
              System (IS-IS) Extensions for Traffic Engineering (TE)",
              RFC 3784, June 2004.
 [BFD]        Katz, D. and D. Ward, "Bidirectional Forwarding
              Detection", Work in Progress.
 [IS-ISv6-TE] Harrison, J., et al. "IPv6 Traffic Engineering in IS-
              IS", Work in Progress, November 2005.
 [OSPFv3-TE]  Ishiguro, K., et al. "Traffic Engineering Extensions to
              OSPF version 3", Work in Progress, April 2006.

Ali, et al. Standards Track [Page 5] RFC 4558 Node-ID Based RSVP Hello June 2006

Authors' Addresses

 Zafar Ali
 Cisco Systems Inc.
 100 South Main St. #200
 Ann Arbor, MI 48104, USA
 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
 Danny Prairie
 Cisco Systems Inc.
 2000 Innovation Dr.,
 Kanata, Ontario, K2K 3E8, Canada
 Phone: (613) 254-3544
 EMail: dprairie@cisco.com
 Dimitri Papadimitriou
 Alcatel
 Fr. Wellesplein 1,
 B-2018 Antwerpen, Belgium
 Phone: +32 3 240-8491
 EMail: dimitri.papadimitriou@alcatel.be

Ali, et al. Standards Track [Page 6] RFC 4558 Node-ID Based RSVP Hello June 2006

Full Copyright Statement

 Copyright (C) The Internet Society (2006).
 This document is subject to the rights, licenses and restrictions
 contained in BCP 78, and except as set forth therein, the authors
 retain all their rights.
 This document and the information contained herein are provided on an
 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
 ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
 INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Intellectual Property

 The IETF takes no position regarding the validity or scope of any
 Intellectual Property Rights or other rights that might be claimed to
 pertain to the implementation or use of the technology described in
 this document or the extent to which any license under such rights
 might or might not be available; nor does it represent that it has
 made any independent effort to identify any such rights.  Information
 on the procedures with respect to rights in RFC documents can be
 found in BCP 78 and BCP 79.
 Copies of IPR disclosures made to the IETF Secretariat and any
 assurances of licenses to be made available, or the result of an
 attempt made to obtain a general license or permission for the use of
 such proprietary rights by implementers or users of this
 specification can be obtained from the IETF on-line IPR repository at
 http://www.ietf.org/ipr.
 The IETF invites any interested party to bring to its attention any
 copyrights, patents or patent applications, or other proprietary
 rights that may cover technology that may be required to implement
 this standard.  Please address the information to the IETF at
 ietf-ipr@ietf.org.

Acknowledgement

 Funding for the RFC Editor function is provided by the IETF
 Administrative Support Activity (IASA).

Ali, et al. Standards Track [Page 7]

/data/webs/external/dokuwiki/data/pages/rfc/rfc4558.txt · Last modified: 2006/06/09 22:06 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki