PCE Working Group H. Ananthakrishnan Internet-Draft Juniper Networks Intended status: Standards Track S. Sivabalan Expires: January 1, 2015 Cisco C. Barth R. Torvi Juniper Networks I. Minei E. Crabbe Google, Inc June 30, 2014 PCEP Extensions for MPSL-TE LSP Path Protection with stateful PCE draft-ananthakrishnan-pce-stateful-path-protection-00.txt Abstract A stateful Path Computation Element (PCE) is capable of computing as well as controlling via Path Computation Element Protocol (PCEP) Multiprotocol Label Switching Traffic Engineering Label Switched Paths (MPLS LSP). Furthermore, it is also possible for a stateful PCE to create, maintain, and delete LSPs. This document describes PCEP extension to associate two or more LSPs to provide end-to-end path protection. 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 January 1, 2015. Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. Ananthakrishnan, et al. Expires January 1, 2015 [Page 1] Internet-Draft Stateful PCE LSP Path Protection June 2014 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 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 . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. PCEP Extensions . . . . . . . . . . . . . . . . . . . . . . . 4 4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.1. State Synchronization . . . . . . . . . . . . . . . . . . 5 4.2. Error Handling . . . . . . . . . . . . . . . . . . . . . 5 5. IANA considerations . . . . . . . . . . . . . . . . . . . . . 6 5.1. Association Type . . . . . . . . . . . . . . . . . . . . 6 5.2. PCEP Errors . . . . . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 7.1. Normative References . . . . . . . . . . . . . . . . . . 6 7.2. Information References . . . . . . . . . . . . . . . . . 7 1. Introduction [RFC5440] describes PCEP for communication between a Path Computation Client (PCC) and a PCE or between one a pair of PCEs. A PCE computes paths for MPLS-TE LSPs based on various constraints and optimization criteria. Stateful pce [I-D.ietf-pce-stateful-pce] specifies a set of extensions to PCEP to enable stateful control of paths such as MPLS TE LSPs between and across PCEP sessions in compliance with [RFC4657]. It includes mechanisms to effect LSP state synchronization between PCCs and PCEs, delegation of control of LSPs to PCEs, and PCE control of timing and sequence of path computations within and across PCEP sessions and focuses on a model where LSPs are configured on the PCC and control over them is delegated to the PCE. Furthermore, a mechanism to dynamically instantiate LSPs on a PCC based on the requests from a stateful PCE or a controller using stateful PCE is specified in [I-D.ietf-pce-pce-initiated-lsp]. Path protection refers to a paradigm in which the working LSP is protected by one or more protection LSP(s). When the working LSP fails, protection LSP(s) is/are activated. When the working LSPs are Ananthakrishnan, et al. Expires January 1, 2015 [Page 2] Internet-Draft Stateful PCE LSP Path Protection June 2014 computed and controlled by the PCE, there is benefit in a mode of operation where protection LSPs are as well. This document specifies a stateful PCEP extension to associate two or more LSPs for the purpose of setting up path protection. The proposed extension covers the following scenarios: 1. A protection LSP is initiated on a PCC by a stateful PCE which retains the control of the LSP. The PCE is responsible for computing the path of the LSP and updating the PCC with the information about the path. 2. A PCC initiates a protection LSP and retains the control of the LSP. The PCC computes the path and updates the PCE with the information about the path as long as it controls the LSP. 3. A PCC initiates a protection LSP and delegates the control of the LSP to a stateful PCE. The PCE may compute the path for the LSP and update the PCC with the information about the path as long as it controls the LSP. Note that protection LSP can be established (e.g., using RSVP-TE signaling) prior to the failure (in which case the LSP is said to me in standby mode) or post failure of the corresponding working LSP according to the operator choice/policy. 2. Terminology The following terminologies are used in this document: AGID: Association Group ID. ERO: Explicit Route Object. LSP: Label Switched Path. PCC: Path Computation Client. PCE: Path Computation Element PCEP: Path Computation Element Protocol. PPAG: Path Protection Association Group. TLV: Type, Length, and Value. Ananthakrishnan, et al. Expires January 1, 2015 [Page 3] Internet-Draft Stateful PCE LSP Path Protection June 2014 3. PCEP Extensions LSPs are not associated by listing the other LSPs with which they interact, but rather by making them belong to an association group referred to as "Path Protection Association Group" (PPAG) in this document. All LSPs join a PPAG individually. PPAG is based on the generic Association object used to associate two or more LSPs specified in [I-D.minei-pce-association-group]. A member of a PPAG can take the role of working or protection LSP. This document defines a new association type called "Path Protection Association Type" of value TBD. A PPAG can have one working LSP and one or more protection LSPs. The source and destination of all LSPs within a PPAG MUST be the same. The format of the Association object used for PPAG is shown in Figure 1: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Type | Generic flags |R| Type-specific flags |S|P| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Association group id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // Optional TLVs // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: The Association Object format Type - TBD for the Path Protection Associaiton Type The description of the flags are as follows: The 'P' Flag indicates whether the LSP associated with the PPAG is working or protection LSP. If this flag is set, the LSP is protection LSP. The 'S' Flag if P flag is set, S flag indicates whether the protection LSP associated with the PPAG is in standby mode (e.g., signaled via RSVP-TE prior to failure). The S flag is ignored if P flag is set to 0. Ananthakrishnan, et al. Expires January 1, 2015 [Page 4] Internet-Draft Stateful PCE LSP Path Protection June 2014 4. Operation A PCE can create/update working and protection LSPs independently. However, it can add a protection LSP to a PPAG only after adding a working LSP to that group. As specified in [I-D.minei-pce-association-group], Association Group ID (AGID) is allocated by PCC. In order to reserve an AGID, PCE sends an association object with AGID of 0 either in PCInitiate message or PCUpd message for a working LSP, with both the P and S flags set to 0. Upon receiving an association object with AGID of 0, PCC MUST allocate a new AGID and send it the PCE via PCRpt message. Once the PCE receives the AGID, it can either create one or more protection LSP(s) and add it/them to the PPAG or simply add already existing LSP(s) to the PPAG. A PCE can remove a protection LSP from a PPAG as specified in [I-D.minei-pce-association-group]. A PCC can associate a set of LSPs under its control for path protection purpose. Similarly, the PCC can remove one or more LSPs under its control from the corresponding PPAG. In both cases, the PCC must report the change in association to PCE(s) via PCRpt message. The forwarding behavior after failure of the protected LSP, in particular how and whether traffic will be load balanced among protection pahts will be detailed in a future version of this document. 4.1. State Synchronization During state synchronization, a PCC MUST report all the existing path protection association groups as well as any path protection flags to PCE(s). Following the state synchronization, the PCE MUST remove all stale path protection associations. 4.2. Error Handling All LSPs (working or protection) within a PPAG MUST have the same source and destination. If a PCE attempts to add an LSP to a PPAG and the source and/or destination of the LSP is/are different from the LSP(s) in the PPAG, the PCC MUST send PCErr with Error-Type= TBD (Path Protection Association Error) and Error-Value = 1 (End points mismatch). Ananthakrishnan, et al. Expires January 1, 2015 [Page 5] Internet-Draft Stateful PCE LSP Path Protection June 2014 5. IANA considerations 5.1. Association Type This document defines a new association type for path protection as follows: +-----------------------+--------------------------+----------------+ | Association Type | Association Name | Reference | | Value | | | +-----------------------+--------------------------+----------------+ | 1 | Path Protection | This | | | Association | document | +-----------------------+--------------------------+----------------+ 5.2. PCEP Errors This document defines new Error-Type and Error-Value related to path protection association as follows: +-------------+------------------------------------+ | Error-Type | Meaning | +-------------+------------------------------------+ | 25 | Path Protection Association error: | | | Error-value=1: End-Points mismatch | +-------------+------------------------------------+ 6. Security Considerations The same security considerations apply in head end as described in [I-D.ietf-pce-pce-initiated-lsp] 7. References 7.1. Normative References [I-D.ietf-pce-pce-initiated-lsp] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "PCEP Extensions for PCE-initiated LSP Setup in a Stateful PCE Model", draft-ietf-pce-pce-initiated-lsp-01 (work in progress), June 2014. [I-D.ietf-pce-stateful-pce] Crabbe, E., Minei, I., Medved, J., and R. Varga, "PCEP Extensions for Stateful PCE", draft-ietf-pce-stateful- pce-09 (work in progress), June 2014. Ananthakrishnan, et al. Expires January 1, 2015 [Page 6] Internet-Draft Stateful PCE LSP Path Protection June 2014 [I-D.minei-pce-association-group] Minei, I., Crabbe, E., Sivabalan, S., Ananthakrishnan, H., Zhang, X., and Y. Tanaka, "PCEP Extensions for establishing relationships between sets of LSPs", draft- minei-pce-association-group-00 (work in progress), June 2014. [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. [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009. 7.2. Information References [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, August 2006. [RFC4657] Ash, J. and J. Le Roux, "Path Computation Element (PCE) Communication Protocol Generic Requirements", RFC 4657, September 2006. [RFC5394] Bryskin, I., Papadimitriou, D., Berger, L., and J. Ash, "Policy-Enabled Path Computation Framework", RFC 5394, December 2008. [RFC5557] Lee, Y., Le Roux, JL., King, D., and E. Oki, "Path Computation Element Communication Protocol (PCEP) Requirements and Protocol Extensions in Support of Global Concurrent Optimization", RFC 5557, July 2009. Authors' Addresses Ananthakrishnan, et al. Expires January 1, 2015 [Page 7] Internet-Draft Stateful PCE LSP Path Protection June 2014 Hariharan Ananthakrishnan Juniper Networks 1194 N Mathilda Ave, Sunnyvale, CA, 94086 USA EMail: hanantha@juniper.net Siva Sivabalan Cisco 2000 Innovation Drive Kananta, Ontaria K2K 3E8 Cananda EMail: msiva@cisco.com Colby Barth Juniper Networks 1194 N Mathilda Ave, Sunnyvale, CA, 94086 USA EMail: cbarth@juniper.net Raveendra Torvi Juniper Networks 1194 N Mathilda Ave, Sunnyvale, CA, 94086 USA EMail: rtorvi@juniper.net Ina Minei Google, Inc 1600 Amphitheatre Parkway Mountain View, CA, 94043 USA EMail: inaminei@google.com Ananthakrishnan, et al. Expires January 1, 2015 [Page 8] Internet-Draft Stateful PCE LSP Path Protection June 2014 Edward Crabbe Google, Inc 1600 Amphitheatre Parkway Mountain View, CA, 94043 USA EMail: edc@google.com Ananthakrishnan, et al. Expires January 1, 2015 [Page 9]