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Network Working Group                                             Z. AliRequest for Comments: 4558                                     R. RahmanCategory: Standards Track                                     D. Prairie                                                           Cisco Systems                                                        D. Papadimitriou                                                                 Alcatel                                                               June 2006Node-ID Based Resource Reservation Protocol (RSVP) Hello:A Clarification StatementStatus 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 20061.  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 20062.1.  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 inRFC 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 inSection 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 20067.  Reference7.1.  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",RFC3630, 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 2006Authors' 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.beAli, et al.                 Standards Track                     [Page 6]

RFC 4558                Node-ID Based RSVP Hello               June 2006Full Copyright Statement   Copyright (C) The Internet Society (2006).   This document is subject to the rights, licenses and restrictions   contained inBCP 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 inBCP 78 andBCP 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 athttp://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]