Internet Engineering Task Force S. Sivabalan Internet-Draft J. Medved Intended status: Informational Cisco Systems, Inc. Expires: July 30, 2013 January 28, 2013 IGP Extensions for Stateful PCE Discovery draft-sivabalan-pce-disco-stateful-00 Abstract When a PCE is a Label Switching Router (LSR) participating in the Interior Gateway Protocol (IGP), or even a server participating in IGP, its presence and path computation capabilities can be advertised using IGP flooding. Such IGP extensions exist for OSPF and ISIS. This document specifies two new PCE capabilities advertised by IGP. 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 July 30, 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 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 Sivabalan & Medved Expires July 30, 2013 [Page 1] Internet-Draft Stateful PCE Discovery January 2013 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Overview of Protocol Extensions . . . . . . . . . . . . . . . 3 4. Backward Compatibility . . . . . . . . . . . . . . . . . . . . 3 5. Management Considerations . . . . . . . . . . . . . . . . . . 3 6. Security Considerations . . . . . . . . . . . . . . . . . . . 3 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 4 8.1. Normative References . . . . . . . . . . . . . . . . . . . 4 8.2. Informative References . . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction [RFC5440] describes the Path Computation Element Protocol (PCEP), which defines the communication between a Path Computation Client (PCC) and a Path Control Element (PCE), or between PCE and PCE, enabling computation of Multiprotocol Label Switching (MPLS) for Traffic Engineering Label Switched Path (TE LSP) characteristics. Stateful PCE [I-D.ietf-pce-stateful-pce] specifies a set of extensions to PCEP to enable stateful control of 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. It focuses on a model where LSPs are configured on the PCC and the LSP's path routing and the timing of its setup is delegated to the PCE. A mechanism for instantiating LSPs on a PCC using stateful PCE is specified in [I-D.crabbe-pce-pce-initiated-lsp]. Such mechanism is considered useful in applications such as Software Defined Networks (SDN), demand engineering, etc. When PCCs are LSRs participating in the IGP (OSPF or IS-IS), and PCEs are either LSRs or servers also participating in the IGP, an effective mechanism for PCE discovery within an IGP routing domain consists of utilizing IGP advertisements. Such extension to OSPF to IS-IS exists in [RFC5088] and [RFC5089], respectively. Currently, the IGP PCE capability does not indicate whether the advertised PCE is stateful or capable to actively instantiate LSPs on a PCC. Advertising such capabilities would facilitate a PCC to learn about available stateful PCEs, as well as about a PCE's capability to instantiate LSPs. A PCC could listen to IGP updates, or use other mechanisms that carry IGP information to interested clients, such as BGP-LS ([I-D.ietf-idr-ls-distribution]). This document extends the IGP capability advertisement mechanism to include stateful PCE and PCE-based LSP instantiation capabilities. 1.1. Requirements 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 RFC 2119 [RFC2119] 2. Terminology Sivabalan & Medved Expires July 30, 2013 [Page 2] Internet-Draft Stateful PCE Discovery January 2013 The following terminology is used in this document: IGP: Interior Gateway Protocol IS-IS: Intermediate System to Intermediate System LSR: Label Switching Router OSPF: Open Shortest Path First PCC: Path Computation Client PCE: Path Computation Element PCEP: Path Computation Element Protocol 3. Overview of Protocol Extensions The PCE-CAP-FLAGS sub-TLV is an optional sub-TLV used to advertise PCE capabilities. It MAY be present within the PCED sub-TLV carried by OSPF or IS-IS. [RFC5088] and [RFC5089] provide the description and processing rules for this sub-TLV when carried within OSPF and IS-IS, respectively. The value field of the PCE-CAP-FLAGS sub-TLV is made up of an array of units of 32-bit flags numbered from the most significant as bit 0, where each bit represents one PCE capability. The PCE-CAP-FLAGS sub-TLV has the following format: o TYPE: 5 o LENGTH: Multiple of 4 o VALUE: This contains an array of units of 32 bit flags with the most significant bit as 0. Each bit represents one PCE capability PCE capability bits are defined in [RFC5088]. This document defines new capability bits for the stateful PCE as follows: Bit Capability 9 Support stateful PCE capability 10 Support PCE-based tunnel instantiation capability 4. Backward Compatibility An LSR that does not support the new IGP PCE capability bits specified in this document silently ignores those bits. 5. Management Considerations TBD. 6. Security Considerations Security considerations described in [RFC5088] are applicable to stateful PCE capabilities. No additional security measures are required. 7. IANA Considerations Sivabalan & Medved Expires July 30, 2013 [Page 3] Internet-Draft Stateful PCE Discovery January 2013 IANA is requested to allocate a new bit in "PCE Capability Flags" registry for stateful PCE capability as follows: Bit Meaning Reference 9 Stateful PCE capability This document 10 PCE-based tunnel instantiation capability This document Table 1 8. References 8.1. Normative References [I-D.crabbe-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", Internet-Draft draft-crabbe-pce-pce-initiated- lsp-00, October 2012. [I-D.ietf-idr-ls-distribution] Gredler, H., Medved, J., Previdi, S., Farrel, A., and S. Ray, "North-Bound Distribution of Link-State and TE Information using BGP", Internet-Draft draft-ietf-idr-ls- distribution-01, October 2012. [I-D.ietf-pce-stateful-pce] Crabbe, E., Medved, J., Minei, I., and R. Varga, "PCEP Extensions for Stateful PCE", Internet-Draft draft-ietf- pce-stateful-pce-02, October 2012. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5088] Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang, "OSPF Protocol Extensions for Path Computation Element (PCE) Discovery", RFC 5088, January 2008. [RFC5089] Le Roux, JL., Vasseur, JP., Ikejiri, Y., and R. Zhang, "IS-IS Protocol Extensions for Path Computation Element (PCE) Discovery", RFC 5089, January 2008. [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009. 8.2. Informative References [RFC4657] Ash, J. and J.L. Le Roux, "Path Computation Element (PCE) Communication Protocol Generic Requirements", RFC 4657, September 2006. Authors' Addresses Sivabalan & Medved Expires July 30, 2013 [Page 4] Internet-Draft Stateful PCE Discovery January 2013 Siva Sivabalan Cisco Systems, Inc. 2000 Innovation Drive Kanata, Ontario K2K 3E8 Canada Email: msiva@cisco.com Jan Medved Cisco Systems, Inc. 170 West Tasman Drive San Jose, CA 95134 USA Email: jmedved@cisco.com Sivabalan & Medved Expires July 30, 2013 [Page 5]