Network Working Group Rajiv Asati Internet Draft Cisco Systems, Inc. Expiration Date: December 2007 Bob Thomas Cisco Systems, Inc. June 2007 LDP End-of-LIB draft-asati-mpls-ldp-end-of-lib-00.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. Copyright Notice Copyright (C) The IETF TRUST (2007). Abstract There are situations following LDP session establishment where it would be useful for an LDP speaker to know when its peer has advertised all of its labels. These include session re-establishment following loss of an LDP session when LDP graceful restart is in use Asati & Thomas [Page 1] Internet Draft draft-asati-mpls-ldp-end-of-lib-00.txt June 2007 and session establishment when LDP-IGP sync is in use. The LDP specification provides no mechanism for an LDP speaker to notify a peer when it has completed its initial label advertisements to that peer. This document specifies means for an LDP speaker to signal completion of its initial label advertisements following session establishment. Table of Contents 1 Introduction .......................................... 2 2 Specification Language ................................ 3 3 Signaling Completion of Initial Label Advertisement ... 3 4 IANA Considerations ................................... 4 5 Security Considerations ............................... 4 6 References ............................................ 4 7 Author Information .................................... 5 8 Intellectual Property Statement ....................... 5 9 Full Copyright Statement .............................. 6 1. Introduction There are situations following LDP session establishment where it would be useful for an LDP speaker to know when its peer has advertised all of its labels. For example, after an LDP session is re-established when LDP graceful restart [RFC3478] is in effect it would be helpful for each peer to signal the other after it has advertised all its label bindings. Similarly when an LDP speaker is using LDP-IGP synchronization procedures [LDPSynch] it would be useful for the speaker to know when its peer has completed advertisement of its IP label bindings. The LDP specification [RFC3036] provides no mechanism for an LDP speaker to notify a peer when it has completed its initial label advertisements to that peer. This document specifies use of a Notification message with the "End- of-LIB" Status Code for an LDP speaker to signal completion of its label advertisements following session establishment. RFC3036 implicitly assumes that new Status Codes will be defined over the course of time. However, it does not explicitly define the behavior of an LDP speaker which does not understand the Status Code Asati & Thomas [Page 2] Internet Draft draft-asati-mpls-ldp-end-of-lib-00.txt June 2007 in a Notification message. To avoid backward compatibility issues this document specifies use of the LDP capability mechanism [LDPCap] at session establishment time for informing a peer that an LDP speaker is capable of processing Notification messages that carry the "End-of-LIB" Status Code. 2. Specification Language 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 [RFC2119]. 3. Signaling Completion of Initial Label Advertisement An LDP speaker MAY include a Capability Parameter in an Initialization message to inform a peer that it is capable of processing Notification Messages that carry a Status TLV with the End-of-LIB Status Code. The Capability Parameter for the End-of-LIB capability is a TLV with the following format: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |U|F| End-of-LIB (IANA) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S| Reserved | +-+-+-+-+-+-+-+-+ where: U and F bits: As specified by RFC3036. End-of-LIB: TLV code point to be assigned by IANA. S-bit: Must be 1 (indicates that cability is being advertised). An LDP speaker MUST NOT send a Notificiation which carries a Status TLV with the End-of-LIB Status Code unless its peer had advertised the End-of-LIB capability during session establishment. If its peer had advertised the End-of-LIB capability during session establishment an LDP speaker MAY signal completion of its label advertisements to the peer by means of a Notification message. Such Asati & Thomas [Page 3] Internet Draft draft-asati-mpls-ldp-end-of-lib-00.txt June 2007 a Notification message MUST carry: - An "End-of-LIB" Status Code in the Status TLV. This is a new Status Code. - A FEC TLV with the Typed Wildcard FEC Element [TypedWC] that identifies the FEC type for which initial label advertisements have been completed. In terms of Section 3.5.1 of RFC3036 this TLV is an "Optional Parameter" of the Notification message. 4. IANA Considerations This draft introduces a new LDP Status Code and a new LDP Capability both of shich require IANA assignment. 5. Security Considerations No security considerations beyond those that apply to the base LDP specification and described in [RFC3036] apply to use of the Typed Wildcard FEC Element defined in this document. 6. References Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC2119, March 1997. [RFC3036] Andersson, L., Doolan, P., Feldman, N., Fredette, A. and Thomas, B., "LDP Specification", RFC 3036, January 2001. [LDPCap] Thomas, B., Aggarwal, S., Aggarwal, R., Le Roux, J.L., "LDP Capabilities", draft-ietf-mpls-ldp-capabilities-00, Work in Progress, May 2007. [TypedWC] Thomas, B., Minei, I., "LDP Typed Wildcard FEC", draft- ietf-mpls-ldp-typed-wildcard-01, Work in Progress, May 2007. Informative References [LDPCap] Thomas, B., Aggarwal, S., Agarwal, R., Le Roux, J.L., "LDP Capabilities", Work in Progreaa, May 2007. Asati & Thomas [Page 4] Internet Draft draft-asati-mpls-ldp-end-of-lib-00.txt June 2007 [LDPSynch] Jork, M., Atlas, A., Fang, L., "LDP IGP Synchronization", draft-jork-ldp-igp-sync-02, Work in Progress, June 2006. [RFC3478] Leelanivas, M., Rekhter, Y., Aggarwal, R., "Graceful Restart Mechanism for Label Distribution Protocol", February 2003. 7. Author Information Rajiv Asati Cisco Systems, Inc. Mail Stop RTP6P/2/1 7025-6 Kit Creek Road PO Box 14987 Research Triangle Park , NORTH CAROLINA 27709-4987 Email: rajiva@cisco.com Bob Thomas Cisco Systems, Inc. 1414 Massachusetts Ave. Boxborough MA 01719 Email: rhthomas@cisco.com 8. 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. Asati & Thomas [Page 5] Internet Draft draft-asati-mpls-ldp-end-of-lib-00.txt June 2007 9. Full Copyright Statement Copyright (C) The IETF Trust (2007). 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, THE IETF TRUST 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. Asati & Thomas [Page 6]