CCAMP Working Group Rakesh Gandhi Internet-Draft Zafar Ali Intended status: BCP Gabriele Maria Galimberti Expires: January 16, 2014 Cisco Systems, Inc. July 15, 2013 RSVP-TE Extensions For Signaling GMPLS Restoration LSP draft-gandhi-ccamp-gmpls-restoration-lsp-01 Abstract In transport networks, there are requirements where Generalized Multi-Protocol Label Switching (GMPLS) recovery scheme need to employ restoration LSP while keeping resources for the working and/ or protecting LSPs reserved in the network. Existing GMPLS recovery procedures do not address these requirements. This document describes best common practice for using RSVP-TE for GMPLS recovery with restoration LSP. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on May 31, 2013. Copyright Notice Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of gandhi, et al. Expires January 16, 2014 [Page 1] Internet-Draft RSVP-TE Signaling for Restoration LSP July 15, 2013 publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . 4 3. Restoration LSP Signaling Extensions . . . . . . . . . . . . . 5 3.1. Signaling Procedure . . . . . . . . . . . . . . . . . . . 5 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 6. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 5 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 7.1. Normative references . . . . . . . . . . . . . . . . . . . 6 7.2. Informative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 gandhi, et al. Expires January 16, 2014 [Page 2] Internet-Draft RSVP-TE Signaling for Restoration LSP July 15, 2013 1. Introduction Generalized Multi-Protocol Label Switching (GMPLS) extends MPLS to include support for different switching technologies [RFC3471] [RFC3473]. These switching technologies provide several protection schemes [RFC4426][RFC4427] (e.g. 1+1, 1:N and M:N). GMPLS RSVP-TE signaling has been extended to support various recovery schemes to establish Label Switched Paths (LSPs) [RFC4872][RFC4873], typically working LSP and protecting LSP. [RFC4427] Section 7 specifies various schemes for GMPLS restoration. In GMPLS recovery schemes currently considered, restoration LSP is signaled after the failure has been detected and notified on the working LSP. These schemes assume that working LSP is removed from the network before restoration LSP is signaled. In transport networks, as working LSPs are typically signaled over a nominal path, there are many scenarios where service providers would like to keep resources associated with the working LSPs reserved. This is to make sure that the service (working LSP) can use the nominal path when the failure is repaired. Consequently, in transport networks one can employ a recovery scheme where a new restoration LSP is signaled while working LSP and/ or protecting LSP are not torn down in control plane due to a failure. Restoration LSP differs from a secondary LSP in the way that secondary LSP does not reserve resources in the data plane and is not able to carry any traffic until it is refreshed whereas restoration LSP does reserve resources and is able to carry traffic. One example of the recovery scheme considered in this draft is 1+R recovery. The 1+R recovery is exemplified in Figure 1. In this example, working LSP on path A-B-C-Z is pre-established. Typically after a failure detection and notification on the working LSP, a second LSP on path A-H-I-J-Z is established as a restoration LSP. Unlike protection LSP, restoration LSP is signaled on as needed basis. A --- B --- C --- Z \ / H --- I --- J Figure 1: An example of 1+R recovery scheme During failure with 1+R recovery scheme, in general, working LSP resources are not released and working and restoration LSPs coexist in the network. Nonetheless, working and restoration LSPs can share gandhi, et al. Expires January 16, 2014 [Page 3] Internet-Draft RSVP-TE Signaling for Restoration LSP July 15, 2013 network resources. Typically when failure is recovered on the working LSP, restoration LSP is no longer required and torn down (e.g. revertive mode). Another example of the recovery scheme considered in this draft is 1+1+R. In 1+1+R, a restoration LSP is signaled for the working LSP and/ or the protecting LSP after the failure has been detected and notified on the working LSP or the protecting LSP. The 1+1+R recovery is exemplified in Figure 2. In this example, working LSP on path A-B- C-Z and protecting LSP on path A-D-E-F-Z are pre-established. After a failure detection and notification on a working LSP or protecting LSP, a third LSP on path A-H-I-J-Z is established as a restoration LSP. The restoration LSP in this case provides protection against a second order failure. Restoration LSP is torn down when the failure on the working or protecting LSP is repaired. D --- E --- F / \ A --- B --- C --- Z \ / H --- I --- J Figure 2: An example of 1+1+R recovery scheme [RFC4872] Section 14 defines PROTECTION object for GMPLS recovery signaling. The PROTECTION object is used to identify primary and secondary LSPs using S bit and protecting and working LSPs using P bit. However, the PROTECTION object does not have a way to identify restoration LSP. [RFC4872] and [RFC6689] define the usage of ASSOCIATION object for further associating GMPLS working and protecting LSPs for the case where restoration LSP is signaled for GMPLS recovery after the working or protecting LSPs are removed. This draft outlines the best common practice for identifying the restoration LSP for GMPLS recovery where working and protecting LSP resources are kept reserved. 2. 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 [RFC2119]. gandhi, et al. Expires January 16, 2014 [Page 4] Internet-Draft RSVP-TE Signaling for Restoration LSP July 15, 2013 3. Restoration LSP Signaling Extensions 3.1. Signaling Procedure Where GMPLS recovery scheme need to employ restoration LSP while keeping resources for the working and/ or protecting LSPs reserved in the network, restoration LSP is signaled with ASSOCIATION object with the association ID set to the LSP ID of the LSP it is restoring. For example, when a restoration LSP is signaled for a working LSP, the ASSOCIATION object in the restoration LSP contains the association ID set to the LSP ID of the working LSP. Similarly, when a restoration LSP is signaled for a protecting LSP, the ASSOCIATION object in the restoration LSP contains the association ID set to the LSP ID of the protecting LSP. The procedure for signaling the PROTECTION object is specified in [RFC4872][RFC4873] and does not change. Restoration LSP for the working LSP is signaled with P bit cleared and restoration LSP for the protecting LSP is signaled with P bit set. When using a GMPLS recovery mode, where working LSP is destroyed, and the restoration LSP is promoted to be the new working LSP, restoration LSP RSVP Path message MUST be refreshed by using the ASSOCIATION_OBJECT.LSP_ID from the destroyed working LSP ASSOCIATION_OBJECT.LSP_ID. When using a GMPLS recovery mode, where a protecting LSP is destroyed, and the restoration LSP is promoted to be the new protecting LSP, restoration LSP RSVP Path message MUST be refreshed by using the ASSOCIATIN_OBJECT.LSP_ID from the destroyed protecting LSP ASSOCIATION_OBJECT.LSP_ID. 4. IANA Considerations This document makes no request for IANA action. 5. Security Considerations This document introduces no additional security considerations. For a general discussion on MPLS and GMPLS related security issues, see the MPLS/GMPLS security framework [RFC5920]. In addition, the considerations specified in [RFC4872] and [RFC4873] will apply. 6. Acknowledgement gandhi, et al. Expires January 16, 2014 [Page 5] Internet-Draft RSVP-TE Signaling for Restoration LSP July 15, 2013 The authors would like to thank George Swallow for the discussion on the GMPLS restoration. 7. References 7.1. Normative references [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997. [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. [RFC3471] Berger, L., Editor, "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description", RFC 3471, January 2003. [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. [RFC4872] Lang, J., Rekhter, Y., and D. Papadimitriou, "RSVP-TE Extensions in Support of End-to-End Generalized Multi- Protocol Label Switching (GMPLS) Recovery", RFC 4872, May 2007. [RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel, "GMPLS Segment Recovery", RFC 4873, May 2007. [RFC6689] Berger, L, "Usage of the RSVP ASSOCIATION Object", RFC 6689, July 2012. gandhi, et al. Expires January 16, 2014 [Page 6] Internet-Draft RSVP-TE Signaling for Restoration LSP July 15, 2013 7.2. Informative References [RFC4426] Lang, J., Rajagopalan B., and D.Papadimitriou, Editors, "Generalized Multiprotocol Label Switching (GMPLS) Recovery Functional Specification", RFC 4426, March 2006. [RFC4427] Mannie, E., Ed. and D. Papadimitriou, Ed., "Recovery (Protection and Restoration) Terminology for Generalized Multi-Protocol Label Switching, RFC 4427, March 2006. [RFC5920] Fang, L., "Security Framework for MPLS and GMPLS Networks", RFC 5920, July 2010. Authors' Addresses Rakesh Gandhi Cisco Systems, Inc. Email: rgandhi@cisco.com Zafar Ali Cisco Systems, Inc. Email: zali@cisco.com Gabriele Maria Galimberti Cisco Systems, Inc. Email: ggalimbe@cisco.com gandhi, et al. Expires January 16, 2014 [Page 7]