Internet Engineering Task Force S. Alvarez Internet-Draft S. Sivabalan Intended status: Standards Track Cisco Systems, Inc. Expires: April 25, 2014 October 22, 2013 PCE Path Profiles draft-alvarez-pce-path-profiles-00 Abstract This document describes extensions to the Path Computation Element (PCE) Communication Protocol (PCEP) to signal path profiles. A stateful or stateless path computation element (PCE) can maintain an association between a set of path parameters and a profile. A PCC can use the path profile to initiate a path computation request without having to specify a detailed list of path parameters. In addition, a PCC can use the path profile to implement local policies associated with a path. 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 April 25, 2014. 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 Alvarez & Sivabalan Expires April 25, 2014 [Page 1] Internet-Draft PCE Path Profiles October 2013 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 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 2. Path Profiles . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.1. Capability Advertisement . . . . . . . . . . . . . . . . 3 3.2. PCC-Initiated Paths . . . . . . . . . . . . . . . . . . . 3 3.2.1. Point-to-Point Paths . . . . . . . . . . . . . . . . 4 3.2.2. Point-to-Multipoint Paths . . . . . . . . . . . . . . 5 3.3. PCE-Initiated Paths . . . . . . . . . . . . . . . . . . . 5 4. Object Extensions . . . . . . . . . . . . . . . . . . . . . . 6 4.1. OPEN Object . . . . . . . . . . . . . . . . . . . . . . . 6 4.2. PATH-PROFILE Object . . . . . . . . . . . . . . . . . . . 6 5. Error Codes for PATH-PROFILE Object . . . . . . . . . . . . . 7 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 7. Security Considerations . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 8.1. Normative References . . . . . . . . . . . . . . . . . . 8 8.2. Informative References . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction 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. Path Profiles A path profile represents a list of path computation parameters or attributes that a PCE owns. The PCC learns that association through the interaction with the PCE. If the PCC initiates the path setup, it uses the path profile as part of the path computation request. In its simplest form, the request will only include mandatory path request objects and a PATH-PROFILE object defined in Section 4.2. The PCE uses the path profile to identify the appropriate path computation parameters. Then, it performs the path computation and sends a reply listing the detailed path parameters used. If the PCE initiates the path setup, the PCE signals the path parameters and includes a PATH-PROFILE object to indicate the path profile id associated with the path. Alvarez & Sivabalan Expires April 25, 2014 [Page 2] Internet-Draft PCE Path Profiles October 2013 3. Procedures 3.1. Capability Advertisement PCEP speakers advertise their capability to support path profiles during the session initialization phase. They include the PATH- PROFILE-CAPABILITY TLV defined in Section 4.1 as part of the OPEN object. A PCEP speaker can only signal a path profile if both speakers advertised this capability. A speaker MUST send a PCErr message with Error-Type=4 (Not supported object), Error-value=1 (Not supported object class) and close the session if it receives a message with a path profile id, it supports the extensions in this document and both speakers did not advertise this capability. 3.2. PCC-Initiated Paths A PCC MAY include a PATH-PROFILE object when sending a PCReq message. The PCE uses the path profile id to select the parameters to fullfil the request. The means by which the PCC learns about a particular path profile id and decides to include it in a PCReq message are outside the scope of this document. Similarly, the means by which the PCE selects a set of parameters based on the profile id for a specific request are outside the scope of this document. The PCE may be stateful or stateless. A PCE may receive a path computation request with an unknown or invalid path profile id. The PCE sends a PCErr message with Error- Type=[TBA] (PATH-PROFILE Error), Error-value=1 (Unknown path profile) if the path profile id is not known to the PCE. The PCE sends a PCErr message with Error-Type=[TBA] (PATH-PROFILE Error), Error- value=2 (Invalid path profile) if the PCE knows about the path profile id, but considers the request invalid. The profile may be invalid because of the path type, the PCEP session type or for the originating PCC. The PCE will determine whether to consider any additional optional objects included in a PCReq message based on policy. As illustrated in Section 3.2.1 and Section 3.2.2, the PCC MAY include other optional objects along with a PATH-PROFILE object as part of a path computation request. The PCC will use the processing-rule (P) flag in the common object header to signal whether it considers those objects mandatory or optional when the PCE performs path computation. Those objects may overlap with the path parameters that the PCE associates with the path profile id. PCE policy may place different kinds of restrictions on PCReq messages that include a PATH-PROFILE object and additional parameters. A PCE MUST send an error message if it receives a Alvarez & Sivabalan Expires April 25, 2014 [Page 3] Internet-Draft PCE Path Profiles October 2013 request with optional objects signaled as mandatory (P flag = 1) for path computation and PCE policy does not allow such behavior from the originating PCC. In that case, the PCE sends a PCErr message with Error-Type=[TBA] (PATH-PROFILE Error), Error-value=3 (Unexpected mandatory object). If the objects are signaled as optional (P flag = 0) for path computation, the PCE will decide based on policy whether to consider them or not. When sending the PCRep message for the request, the PCE will use the ignore (I) flag in the common object header to indicate to the PCC whether an object was ignored. 3.2.1. Point-to-Point Paths [RFC5440] defines the basic structure of a PCReq message for point- to-point paths. This documents extends the message format as follows: ::= [] where: ::=[] ::=[] ::= [] [] where: is the list of optional objects used for path computation as defined initially in [RFC5440] and modified in subsequent PCEP extensions. If present in a PCReq message, the PATH-PROFILE object MUST be the first optional object in the request portion of the message. Alvarez & Sivabalan Expires April 25, 2014 [Page 4] Internet-Draft PCE Path Profiles October 2013 3.2.2. Point-to-Multipoint Paths [RFC6006] defines the basic structure of a PCReq message for point- to-multipoint paths. This documents extends the message format as follows: TBD 3.3. PCE-Initiated Paths A PCE MAY include a PATH-PROFILE object when sending a PCInitiate message as defined in [I-D.crabbe-pce-pce-initiated-lsp]. The PCC can use the path profile id to select local behavior to apply to the path. The means by which the PCE selects a profile id for a specific PCInitiate message are outside the scope of this document. Similarly, the means by which the PCC selects the local behavior to apply to a path based on a path profile id are outside the scope of this document. [I-D.crabbe-pce-pce-initiated-lsp] defines the basic structure of a PCInitiate message. This documents extends the message format as follows: ::= Where: ::= [] ::= (| ) ::= [PATH-PROFILE> [] ::= where: Alvarez & Sivabalan Expires April 25, 2014 [Page 5] Internet-Draft PCE Path Profiles October 2013 is defined in [RFC5440] and extended by PCEP extensions. 4. Object Extensions 4.1. OPEN Object This documents defines a new optional PATH-PROFILE-CAPABILITY TLV in the OPEN object. 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=[TBA] | Length=4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ PATH-PROFILE-CAPABILITY TLV Figure 1 Reserved (16 bits): MUST be set to zero on transmission and ignored on recepit. Flags (16 bits): Unassigned bits are considered reserved. They MUST be set to zero on transmission and ignored on recepit. No flags are currently defined. 4.2. PATH-PROFILE Object The PATH-PROFILE object may be carried in PCReq, PCInitiate and PCUpd messages. PATH-PROFILE Object-Class is [TBA]. PATH-PROFILE Object-Type is 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | Path Profile Id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Optional TLVs // | | Alvarez & Sivabalan Expires April 25, 2014 [Page 6] Internet-Draft PCE Path Profiles October 2013 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ PATH-PROFILE Object Figure 2 Reserved (16 bits): MUST be set to zero on transmission and ignored on recepit. Path Profile Id (16 bits): (non-zero) unsigned path profile identifier. The PATH-PROFILE object has a variable length and may contain additional TLVs. No TLVs are currently defined. 5. Error Codes for PATH-PROFILE Object Error-Type Meaning Error-Value PATH-PROFILE Error 1: Unknown path profile 2: Invalid path profile 3: Unexpected mandatory object 6. IANA Considerations IANA is requested to assign the following code points. PATH-PROFILE-CAPABILITY TLV PATH-PROFILE Object-Class PATH-PROFILE Object-Type PATH-PROFILE Error-Type 7. Security Considerations TBD 8. References Alvarez & Sivabalan Expires April 25, 2014 [Page 7] Internet-Draft PCE Path Profiles October 2013 8.1. Normative References [I-D.ali-pce-remote-initiated-gmpls-lsp] Ali, Z., Sivabalan, S., Filsfils, C., Varga, R., Lopez, V., and O. Dios, "Path Computation Element Communication Protocol (PCEP) Extensions for remote-initiated GMPLS LSP Setup", draft-ali-pce-remote-initiated-gmpls-lsp-01 (work in progress), July 2013. [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", draft-crabbe-pce-pce-initiated-lsp-03 (work in progress), October 2013. [I-D.ietf-pce-gmpls-pcep-extensions] Margaria, C., Dios, O., and F. Zhang, "PCEP extensions for GMPLS", draft-ietf-pce-gmpls-pcep-extensions-08 (work in progress), July 2013. [I-D.ietf-pce-stateful-pce] Crabbe, E., Medved, J., Minei, I., and R. Varga, "PCEP Extensions for Stateful PCE", draft-ietf-pce-stateful- pce-07 (work in progress), October 2013. [I-D.sivabalan-pce-segment-routing] Sivabalan, S., Medved, J., Filsfils, C., Crabbe, E., and R. Raszuk, "PCEP Extensions for Segment Routing", draft- sivabalan-pce-segment-routing-02 (work in progress), October 2013. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009. [RFC6006] Zhao, Q., King, D., Verhaeghe, F., Takeda, T., Ali, Z., and J. Meuric, "Extensions to the Path Computation Element Communication Protocol (PCEP) for Point-to-Multipoint Traffic Engineering Label Switched Paths", RFC 6006, September 2010. 8.2. Informative References [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, August 2006. Alvarez & Sivabalan Expires April 25, 2014 [Page 8] Internet-Draft PCE Path Profiles October 2013 Authors' Addresses Santiago Alvarez Cisco Systems, Inc. 170 West Tasman Drive San Jose, CA 95134 USA Email: saalvare@cisco.com Siva Sivabalan Cisco Systems, Inc. 2000 Innovation Drive Kanata, ON K2K-3E8 Canada Email: msiva@cisco.com Alvarez & Sivabalan Expires April 25, 2014 [Page 9]