Network Working Group J.L. Le Roux (Editor) France Telecom IETF Internet Draft J.P. Vasseur (Editor) Cisco System Inc. Proposed Status: Standard Track Seisho Yasukawa Expires: January 2007 NTT July 2006 Routing extensions for discovery of P2MP TE LSP Leaf LSRs draft-leroux-mpls-p2mp-te-autoleaf-01.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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 The setup of a Point To MultiPoint (P2MP) Traffic Engineering Label Switched Path (TE LSP) requires the head-end Label Switching Router (LSR) to be aware of all leaf LSRs. This may require the potentially cumbersome configuration of potentially a large number of leaf LSRs on the P2MP TE LSP head-end LSR. Also leaf LSRs may want to dynamically join or leave a P2MP TE LSP without requiring manual configuration on the head-end LSR. This document specifies IGP Le Roux, Vasseur, Yasukawa [Page 1] Internet Draft draft-leroux-mpls-p2mp-te-autoleaf-01.txt June 2006 routing extensions for ISIS and OSPF so as to provide an automatic discovery of the set of leaf LSRs members of a P2MP TE-LSP, also referred to as a P2MP TE Group, in order to automate the creation and modification of such P2MP TE LSP. 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. Table of Contents 1. Terminology.................................................2 2. Introduction................................................2 3. P2MP TE Group...............................................3 3.1. Description.................................................3 3.2. Required Information........................................3 4. P2MP-TE-GROUP TLV formats...................................4 4.1. OSPF P2MP-TE-GROUP TLV format...............................4 4.2. IS-IS P2MP-TE-GROUP TLV format..............................5 5. Elements of procedure.......................................6 5.1. OSPF........................................................6 5.2. ISIS........................................................7 6. Backward compatibility......................................8 7. IANA Considerations.........................................8 7.1. OSPF........................................................8 7.2. ISIS........................................................8 8. Security Considerations.....................................8 9. References..................................................8 9.1. Normative references........................................8 9.2. Informative References......................................9 10. Authors' Address...........................................10 11. Intellectual Property Statement............................10 1. Terminology This document uses terminologies defined in [RFC3031], [RFC3209], [RFC4461], and [P2MP-RSVP-TE]. 2. Introduction [P2MP-RSVP] defines RSVP-TE extensions for setting up P2MP TE LSPs, with one ingress LSR and a set of one or more egress LSRs (leaves). The setup of a P2MP TE LSP requires the ingress LSR to be aware of all leaf LSRs. In operational networks P2MP TE LSPs may comprise a significant number of leaf LSRs and this may require cumbersome configuration on the Ingress LSR, prone to misconfiguration. Also Leaf LSRs may desire to dynamically join or leave a P2MP TE LSP. Le Roux, Vasseur, Yasukawa [Page 2] Internet Draft draft-leroux-mpls-p2mp-te-autoleaf-01.txt June 2006 Hence an automatic mechanism for discovering the leaf LSRs that want to join or leave a P2MP TE LSP is desired. This document specifies IGP (OSPF and IS-IS) extensions so as to automatically discover the leaf LSRs of a P2MP TE LSP also referred to as a "P2MP TE Group". Note that the mechanism(s) needed for the dynamic creation of P2MP TE LSPs and dynamic Leaf addition/removal (grafting/pruning), is implementation specific and outside the scope of this document. An implementation should take special care of implementing the appropriate dampening mechanisms to avoid any unacceptable impact on the IGP scalability. Routing extensions have been defined in [OSPF-CAP] and [ISIS-CAP] in order to advertise router capabilities. This document specifies IGP (OSPF and ISIS) P2MP TE Group TLVs allowing for the automatic discovery of a P2MP TE LSP leaf LSR, to be carried in the OSPF Router Information LSA [OSPF-CAP] and ISIS Router Capability TLV [ISIS-CAP]. 3. P2MP TE Group 3.1. Description A P2MP TE Group is defined as the set of leaf LSRs of a P2MP TE LSP. Routing extensions are specified in this document allowing for dynamic discovery of the P2MP TE Group members. Procedures are also specified for a member to join or leave a P2MP TE group. An LSR may belong to multiple P2MP TE Group. 3.2. Required Information This document specifies a P2MP-TE-GROUP TLV that indicates the set of P2MP TE Group(s) an LSR belongs to. For each P2MP TE group membership announced by an LSR, the P2MP-TE-GROUP TLV advertises the following information: - A P2MP TE group number identifying the P2MP TE group the LSR belongs to; - A Leaf LSR address used by the Ingress LSR to signal a S2L sub-LSP to the advertising LSR for this P2MP TE group. Le Roux, Vasseur, Yasukawa [Page 3] Internet Draft draft-leroux-mpls-p2mp-te-autoleaf-01.txt June 2006 4. P2MP-TE-GROUP TLV formats 4.1. OSPF P2MP-TE-GROUP TLV format The format of the OSPF P2MP-TE-GROUP TLV is the same as the TLV format used by the Traffic Engineering Extensions to OSPF [OSPF-TE]. That is, the TLV is composed of 2 octets for the type, 2 octets specifying the TLV length and a value field. The TLV is padded to four-octet alignment; padding is not included in the length field (so a three octet value would have a length of three, but the total size of the TLV would be eight octets). The OSPF P2MP-TE-GROUP TLV is used to advertise the desire of an LSR to join/leave a given P2MP TE LSP. The OSPF IPv4 P2MP-TE-GROUP TLV (advertised in an OSPF router information LSA defined in [OSPF-CAP]) has the following format: TYPE: To be assigned by IANA (Suggested Value: 5) LENGTH: Variable VALUE: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | P2MP TE Group Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Leaf LSR IPv4 address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 - IPv4 P2MP-TE-GROUP TLV format The OSPF IPv6 P2MP-TE-GROUP TLV (advertised in an OSPF router information LSA defined in [OSPF-CAP]) has the following format: TYPE: To be assigned by IANA (Suggested Value: 6) LENGTH: Variable VALUE: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | P2MP TE Group Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | Leaf LSR IPv6 address | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2 - IPv6 P2MP-TE-GROUP TLV format Le Roux, Vasseur, Yasukawa [Page 4] Internet Draft draft-leroux-mpls-p2mp-te-autoleaf-01.txt June 2006 For each P2MP TE group announced by the LSR, the P2MP-TE-GROUP TLV comprises: - A P2MP TE group number that identifies the P2MP TE group. - A Leaf-LSR address: an IPv4 or IPv6 IP address to be used as S2L sub-LSP destination address for the corresponding P2MP TE group. 4.2. IS-IS P2MP-TE-GROUP TLV format The IS-IS P2MP-TE-GROUP TLV is composed of 1 octet for the type, 1 octet specifying the TLV length and a value field. The format of the P2MP-TE-GROUP TLV is identical to the TLV format used by the Traffic Engineering Extensions for IS-IS [RFC3784]. The ISIS P2MP-TE-GROUP TLV is used to advertise the desire of an LSR to join/leave a given P2MP TE LSP. The ISIS IPv4 P2MP-TE-GROUP TLV (advertised in an IS-IS Router Capability TLV defined in [ISIS-CAP]) has the following format: TYPE: To be assigned by IANA (Suggested Value: 5) LENGTH: Variable VALUE: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | P2MP TE Group Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Leaf LSR IPv4 address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 - IPv4 P2MP-TE-GROUP TLV format The ISIS IPv6 P2MP-TE-GROUP TLV (advertised in an OSPF router information LSA defined in [OSPF-CAP]) has the following format: TYPE: To be assigned by IANA (Suggested Value: 6) LENGTH: Variable VALUE: Le Roux, Vasseur, Yasukawa [Page 5] Internet Draft draft-leroux-mpls-p2mp-te-autoleaf-01.txt June 2006 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | P2MP TE Group Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | Leaf LSR IPv6 address | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4 - IPv6 P2MP-TE-GROUP TLV format For each P2MP TE group announced by the LSR, the ISIS P2MP-TE-GROUP TLV comprises: - A P2MP TE group number that identifies the P2MP TE group. - A Leaf-LSR address: an IPv4 or IPv6 IP address to be used as S2L sub-LSP destination address, for the corresponding P2MP TE group. 5. Elements of procedure 5.1. OSPF The P2MP-TE-GROUP TLV is advertised, within an OSPFv2 Router Information LSA (Opaque type of 4 and Opaque ID of 0) or OSPFv3 Router information LSA (function code of 12) which are defined in [OSPF-CAP]. As such, elements of procedure are inherited from those defined in [OSPF-CAP]. The P2MP-TE-GROUP TLV is OPTIONAL and must at most appear once in an OSPF Router Information LSA. In OSPFv2 the flooding scope is controlled by the opaque LSA type (as defined in [RFC2370]) and in OSPFv3 by the S1/S2 bits (as defined in [OSPFv3]). The P2MP-TE-GROUP TLV flooding scope will depend on the P2MP TE LSP Ingress LSR and leaf LSRs location: - If the Ingress LSR and generating LSR are located within the same area, the P2MP-TE-GROUP TLV MUST be generated within an OSPFV2 type 10 Router Information LSA or an OSPFV3 Router Information LSA with the S1 bit set and the S2 bit cleared. - If the Ingress LSR and generating LSRs are located within distinct areas, the P2MP-TE-GROUP TLV MUST be generated within an OSPFV2 type 11 Router Information LSA or an OSPFV3 Router Information LSA with the S1 bit cleared and the S2 bit set. Le Roux, Vasseur, Yasukawa [Page 6] Internet Draft draft-leroux-mpls-p2mp-te-autoleaf-01.txt June 2006 A router MUST originate a new OSPF router information LSA whenever the content of the any of the advertised P2MP-TE-GROUP TLV changes or whenever required by the regular OSPF procedure (LSA refresh (every LSRefreshTime)). If an LSR desires to join or leave a particular P2MP TE group, it MUST originate a new OSPF Router Information LSA comprising the updated P2MP-TE-GROUP TLV. In the case of a join a new entry will be added to the P2MP-TE-GROUP TLV; conversely if the LSR leaves a P2MP TE group the corresponding entry will be removed from the P2MP-TE-GROUP TLV. Note that both operations can be performed in the context of a single refresh. An implementation SHOULD be able to detect any change to a previously received P2MP-TE-GROUP TLV from a specific LSR. *Editorial note: Discussion on the number of groups and frequency of changes to be added* 5.2. ISIS The P2MP-TE-GROUP TLV is advertised, within the IS-IS Router CAPABILITY TLV defined in [ISIS-CAP]. As such, elements of procedure are inherited from those defined in [ISIS-CAP]. The P2MP-TE-GROUP TLV is OPTIONAL and must at most appear once in an ISIS Router CAPABILITY TLV. The P2MP-TE-GROUP TLV flooding scope will depend on the P2MP TE LSP Ingress LSR and leaf LSRs location: - If the Ingress LSR and generating LSR are located within a single IS-IS area/level, the P2MP-TE-GROUP TLV MUST not be leaked across IS-IS level/area and the S flag of the Router CAPABILITY TLV MUST be cleared. - If the Ingress LSR and generating LSRs are located within distinct IS-IS area/level, the P2MP-TE-GROUP TLV MUST be leaked across IS- IS level/area and the S flag of the Router CAPABILITY TLV MUST be set. An IS-IS router MUST originate a new IS-IS LSP whenever the content of the any of the advertised P2MP-TE-GROUP TLV changes or whenever required by the regular IS-IS procedure (LSP refresh). If an LSR desires to join or leave a particular P2MP TE group, it MUST originate a new LSP comprising the updated P2MP-TE-GROUP TLV. In the case of a join a new entry will be added to the P2MP-TE-GROUP TLV; conversely if the LSR leaves a P2MP TE group the corresponding entry will be removed from the P2MP-TE-GROUP TLV. Note that both operations can be performed in the context of a single refresh. An implementation SHOULD be able to detect any change to a previously received P2MP-TE-GROUP TLV from a specific LSR. *Editorial note: Discussion on the number of groups and frequency of changes to be added* Le Roux, Vasseur, Yasukawa [Page 7] Internet Draft draft-leroux-mpls-p2mp-te-autoleaf-01.txt June 2006 6. Backward compatibility The P2MP-TE-GROUP TLVs defined in this document do not introduce any interoperability issue. For OSPF, a router not supporting the P2MP-TE-GROUP TLV MUST just silently ignore the TLV as specified in [OSPF-CAP]. For IS-IS a router not supporting the P2MP-TE-GROUP TLV MUST just silently ignore the TLV as specified in [IS-IS-CAP]. 7. IANA Considerations 7.1. OSPF IANA is in charge of the assignment of TLV code points for the Router Information LSA defined in [OSPF-CAP]. IANA will assign a new codepoint for the P2MP-TE-GROUP TLV defined in this document and carried within the Router Information LSA. IPv4 P2MP-TE-GROUP TLV (suggested value=5) IPv6 P2MP-TE-GROUP TLV (suggested value=6) 7.2. ISIS IANA is in charge of the assignment of TLV code points for the IS-IS Router CAPABILITY TLV defined in [ISIS-CAP]. IANA will assign a new codepoint for the P2MP-TE-GROUP TLV defined in this document and carried within the IS-IS Router CAPABILITY TLV. IPv4 P2MP-TE-GROUP TLV (suggested value=5) IPv6 P2MP-TE-GROUP TLV (suggested value=6) 8. Security Considerations No new security issues are raised in this document. 9. References 9.1. Normative references [RFC] Bradner, S., "Key words for use in RFCs to indicate requirements levels", RFC 2119, March 1997. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Le Roux, Vasseur, Yasukawa [Page 8] Internet Draft draft-leroux-mpls-p2mp-te-autoleaf-01.txt June 2006 [RFC3667] Bradner, S., "IETF Rights in Contributions", BCP 78, RFC 3667, February 2004. [BCP79] Bradner, S., "Intellectual Property Rights in IETF Technology", RFC 3979, March 2005. [OSPF-v2] Moy, J., "OSPF Version 2", RFC 2328, April 1998. [OSPF-v3] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6", RFC 2740, December 1999. [RFC2370] Coltun, R., "The OSPF Opaque LSA Option", RFC 2370, July 1998. [IS-IS] "Intermediate System to Intermediate System Intra-Domain Routing Exchange Protocol " ISO 10589. [IS-IS-IP] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and dual environments", RFC 1195, December 1990. [OSPF-TE] Katz, D., Yeung, D., Kompella, K., "Traffic Engineering Extensions to OSPF Version 2", RFC 3630, September 2003. [IS-IS-TE] Li, T., Smit, H., "IS-IS extensions for Traffic Engineering", RFC 3784, June 2004. [OSPF-CAP] Lindem, A., Shen, N., Aggarwal, R., Shaffer, S., Vasseur, J.P., "Extensions to OSPF for advertising Optional Router Capabilities", draft-ietf-ospf-cap, work in progress. [IS-IS-CAP] Vasseur, J.P. et al., "IS-IS extensions for advertising router information", draft-ietf-isis-caps, work in progress. [RSVP-P2MP] Aggarwal, Papadimitriou, Yasukawa, et. al. "Extensions to RSVP-TE for point-to-multipoint TE LSPs", draft-ietf-mpls-rsvp-te- p2mp, work in progress. 9.2. Informative References [P2MP-REQ] Yasukawa, S., et. al., "Signaling Requirements for Point to Multipoint Traffic Engineered MPLS LSPs", RFC4461, April 2006. Le Roux, Vasseur, Yasukawa [Page 9] Internet Draft draft-leroux-mpls-p2mp-te-autoleaf-01.txt June 2006 10. Authors' Address Jean-Louis Le Roux (Editor) France Telecom 2, avenue Pierre-Marzin 22307 Lannion Cedex FRANCE Email: jeanlouis.leroux@francetelecom.com Jean-Philippe Vasseur (Editor) Cisco Systems, Inc. 1414 Massachusetts Avenue Boxborough , MA - 01719 USA Email: jpv@cisco.com Seisho Yasukawa NTT Corporation 9-11, Midori-Cho 3-Chome Musashino-Shi, Tokyo 180-8585, Japan 11. Intellectual Property Statement 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. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS Le Roux, Vasseur, Yasukawa [Page 10] Internet Draft draft-leroux-mpls-p2mp-te-autoleaf-01.txt June 2006 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. 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. Le Roux, Vasseur, Yasukawa [Page 11]