CCAMP Working Group Zafar Ali Reshad Rahman Danny Prairie Cisco Systems, Inc. Internet Draft Category: Informational Expires: August 2004 February 2004 Node ID based RSVP Hello: A Clarification Statement draft-ali-ccamp-rsvp-node-id-based-hello-00.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. 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 failure detection. Nonetheless, this implied behavior is unclear and this informational draft clarifies use of node-id based RSVP Hellos. 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 clarifies use of node-id based RSVP Hellos. Z. Ali, et al. Page 1 2/5/2004 [Page 1] draft-ali-ccamp-rsvp-node-id-based-hello-00.txt February 2004 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 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 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 Author's Addresses................................................4 1. Terminology Node-id: Router-id as defined in the Router Address TLV for OSPF [OSPF-TE] and Traffic Engineering router ID TLV for ISIS [ISIS-TE]. 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 was introduced in [RFC 3209]. The usage of RSVP Hello protocol is over-loaded in [RFC 3473] to support RSVP Graceful Restart (GR) procedures. Specifically, [RFC 3473] specifies the use of the RSVP Hello protocol 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 information is carried over a control network, which may be physically different than 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]. One of the consequences of separation of data bearer links from control channels is that RSVP Hellos are not exchanged over data links; instead hellos use the control channel. Consequently, the use of RSVP Hellos for GR applications introduces a need for node-id based Hellos. Nonetheless, this implied behavior is unclear and this draft clarifies the usage. Z. Ali, et al. Page 2 2/5/2004 [Page 2] draft-ali-ccamp-rsvp-node-id-based-hello-00.txt February 2004 Another scenario which introduces the need for node-id based Hellos is when nodes support unnumbered TE links. Specifically, when all TE links between neighbor nodes are unnumbered, it is implied that the nodes will use node-id based Hellos for detecting node failures. This draft 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 use of node-id based Hellos is also optimal for detection of nodal failures. 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. 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 with its neighbor. If all interfaces between a pair of nodes are unnumbered, the optimal way to use RSVP to detect nodal failure is to run node-id based Hellos. Similarly, 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, if all interfaces between a pair of nodes are unnumbered or when link level failure detection is performed by some means other than RSVP Hellos, a node MUST run node-id based Hellos for node failure detection. Nonetheless, if it is desirable to distinguish between node and link failures, node id based Hellos can co-exist with interface bound Z. Ali, et al. Page 3 2/5/2004 [Page 3] draft-ali-ccamp-rsvp-node-id-based-hello-00.txt February 2004 Hellos. 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 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] remain relevant. 6. Acknowledgements 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. Reference [RFC2205] " 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, 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. [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). [ISIS-TE] Li, T., Smit, H., "IS-IS extensions for Traffic Engineering", draft-ietf-isis-traffic-04.txt (work in progress) [BFD] Katz, D., and Ward, D., "Bidirectional Forwarding Detection", draft-katz-ward-bfd-01.txt (work in progress). Author's Addresses Zafar Ali Cisco Systems Inc. Z. Ali, et al. Page 4 2/5/2004 [Page 4] draft-ali-ccamp-rsvp-node-id-based-hello-00.txtFebruary 2004 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)-254-3519 Email: dprairie@cisco.com Z. Ali, et al. Page 5 2/5/2004 [Page 5]