PCE Working Group D. Dhody Internet-Draft Q. Wu Intended status: Standards Track Huawei Technologies Expires: January 6, 2016 July 5, 2015 Path Computation Element communication Protocol extension for relationship between LSPs and Attributes draft-dhody-pce-association-attr-02 Abstract The Path Computation Element (PCE) provides functions of path computation in support of traffic engineering in networks controlled by Multi-Protocol Label Switching (MPLS) and Generalized MPLS (GMPLS). This document defines a mechanism to create associations between a set of LSPs and a set of attributes (such as configuration parameters, policy or behaviours). 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 6, 2016. Copyright Notice Copyright (c) 2015 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 Dhody & Wu Expires January 6, 2016 [Page 1] Internet-Draft ASSOC-ATTR July 2015 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 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.1. Opaque Identifier . . . . . . . . . . . . . . . . . . . . 3 3.2. Policy based Constraints . . . . . . . . . . . . . . . . 4 3.3. Bundled requests . . . . . . . . . . . . . . . . . . . . 4 4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5. Attribute Association Group . . . . . . . . . . . . . . . . . 5 5.1. ATTRIBUTE-OBJECT-TLV . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 7.1. Association object Type Indicators . . . . . . . . . . . 7 7.2. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 7 8. Manageability Considerations . . . . . . . . . . . . . . . . 8 8.1. Control of Function and Policy . . . . . . . . . . . . . 8 8.2. Information and Data Models . . . . . . . . . . . . . . . 8 8.3. Liveness Detection and Monitoring . . . . . . . . . . . . 8 8.4. Verify Correct Operations . . . . . . . . . . . . . . . . 8 8.5. Requirements On Other Protocols . . . . . . . . . . . . . 8 8.6. Impact On Network Operations . . . . . . . . . . . . . . 8 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 10.1. Normative References . . . . . . . . . . . . . . . . . . 9 10.2. Informative References . . . . . . . . . . . . . . . . . 9 Appendix A. Contributor Addresses . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction [RFC5440] describes the Path Computation Element communication Protocol (PCEP) which enables the communication between a Path Computation Client (PCC) and a Path Control Element (PCE), or between two PCEs based on the PCE architecture [RFC4655]. [I-D.minei-pce-association-group] introduces a generic mechanism to create a grouping of LSPs which can then be used to define associations between a set of LSPs and a set of attributes (such as configuration parameters or behaviours) and is equally applicable to the active and passive modes of a stateful PCE and a stateless PCE. Dhody & Wu Expires January 6, 2016 [Page 2] Internet-Draft ASSOC-ATTR July 2015 This document specifies a PCEP extension to associate one or more LSPs with a set of attributes, which includes, but not limited to - o Configured Parameters o Policies o Behaviour 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 [RFC2119]. 2. Terminology The following terminology is used in this document. AAG: Attribute Association Group. LSR: Label Switch Router. MPLS: Multiprotocol Label Switching. PCC: Path Computation Client. Any client application requesting a path computation to be performed by a Path Computation Element. PCE: Path Computation Element. An entity (component, application, or network node) that is capable of computing a network path or route based on a network graph and applying computational constraints. PCEP: Path Computation Element Communication Protocol. 3. Motivation This section discusses in more detail the motivation and use cases for such an association including but not limited to - 3.1. Opaque Identifier An opaque identifier may represent attributes such as configured parameters or constraints that a PCEP speaker may invoke on a peer. Thus a PCEP speaker may only need an opaque identifier to invoke these attributes (parameters or constraints) rather than encoding them explicitly in each PCEP message. Dhody & Wu Expires January 6, 2016 [Page 3] Internet-Draft ASSOC-ATTR July 2015 3.2. Policy based Constraints In the context of policy-enabled path computation [RFC5394], path computation policies may be applied at both a PCC and a PCE. Consider an Label Switch Router (LSR) with a policy enabled PCC, it receives a service request via signaling, including over a Network- Network Interface (NNI) or User Network Interface (UNI) reference point, or receives a configuration request over a management interface to establish a service. The PCC may also apply user- or service-specific policies to decide how the path selection process should be constrained, that is, which constraints, diversities, optimization criterion, and constraint relaxation strategies should be applied in order for the service LSP(s) to have a likelihood to be successfully established and provide necessary QoS and resilience against network failures. The user- or service-specific policies applied to PCC and are then passed to the PCE along with the Path computation request, in the form of constraints [RFC5394]. PCEP speaker can use the generic mechanism as per [I-D.minei-pce-association-group] to associate a set of LSPs with policy and its resulting path computation constraints. This simplified the path computation message exchanges. 3.3. Bundled requests In some scenarios(e.g.,the topology example described in Section 4.6 of [RFC6805]), there is a need to send multiple requests with the same constraints and attributes to the PCE. Currently these requests are either sent in a separate path computation request (PCReq) messages or bundled together in one (or more) PCReq messages. In either case, the constraints and attributes need to be encoded separately for each request even though they are exactly identical. If a association is used to identify these constraints and attributes shared by multiple requests and grouped together via association mechanism, thus simplifying the path computation message exchanges. 4. Overview As per [I-D.minei-pce-association-group], LSPs are associated with other LSPs with which they interact by adding them to a common association group. This grouping can then be used to define associations between sets of LSPs or between a set of LSPs and a set of attributes (such as configuration parameters or behaviors). A new optional Association Object is defined. This document uses the same association for attributes, called Attribute Association Group (AAG) based on the generic Association object. This document defines a new association type called "Attribute Association Type" of value TBD. Dhody & Wu Expires January 6, 2016 [Page 4] Internet-Draft ASSOC-ATTR July 2015 An AAG can have one or more LSPs and its associated attributes. The scope and handling of AAG identifier is similar to the generic association identifier defined in [I-D.minei-pce-association-group]. One or more LSP are grouped via a single group identifier as defined in [I-D.minei-pce-association-group]. The attributes that may be associated with this set of LSPs may either are - o known to the PCEP peers via some external means like configuration, policy enforcement etc (can be considered as 'out- of-band'). PCEP speaker simply use the AAG identifier in the PCEP message and the peer is supposed to be aware of the associated attributes. This is suitable for stateless PCE where the PCEP peers should be aware of the association and its significance outside of the protocol. o or communicated to the PCEP peer via PCEP itself on first use (can be considered as 'in-band'). PCEP speaker creates a new AAG by using a new identifier and the associated attributes are communicated via TLVs in association object. This is applicable for stateful PCE only. Error handling would be taken up in future revision. 5. Attribute Association Group The format of the generic Association object used for AAG is shown in Figure 1: Dhody & Wu Expires January 6, 2016 [Page 5] Internet-Draft ASSOC-ATTR July 2015 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 | Flags |R| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Association ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Association Source | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // Optional TLVs // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 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 | Flags |R| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Association ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | IPv6 Association Source | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // Optional TLVs // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: The Association Object formats Type - TBD for the Attribute Association Type. AAG may carry optional TLVs including but not limited to - o ATTRIBUTE-OBJECT-TLV: Used to communicate associated attributes in form of PCEP objects, described in this document. o VENDOR-INFORMATION-TLV: Used to communicate arbitrary behavioural information, described in [RFC7150]. 5.1. ATTRIBUTE-OBJECT-TLV The ATTRIBUTE-OBJECT-TLV(s) maybe included in AAG object to associate attributes encoded in PCEP objects. The format of the ATTRIBUTE-OBJECT-TLV is shown in the following figure: Dhody & Wu Expires January 6, 2016 [Page 6] Internet-Draft ASSOC-ATTR July 2015 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=[TBD] | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Object-Class | OT |Res|P|I| Object Length (bytes) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // (Object body) // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: ATTRIBUTE-OBJECT-TLV format The type of the TLV is [TBD] and it has a variable length. The value part consist of a PCEP object (including common header [RFC5440] identifying the object) that is associated with this AAG. This TLV identifies the attributes associated with this group. For each attribute a separate TLV is used. Future PCEP message exchanges may only carry the AAG. 6. Security Considerations This document defines a new type for association and a new ATTRIBUTE- OBJECT-TLV which do not add any new security concerns beyond those discussed in [RFC5440], [I-D.ietf-pce-stateful-pce] and [I-D.minei-pce-association-group] in itself. Some deployments may find these associations and their implications as extra sensitive and thus should employ suitable PCEP security mechanisms like TCP-AO or [I-D.ietf-pce-pceps]. 7. IANA Considerations 7.1. Association object Type Indicators This document defines the following new association type originally defined in [I-D.minei-pce-association-group]. Value Name Reference TBD Attribute Association Type [This I.D.] 7.2. PCEP TLV Type Indicators This document defines the following new PCEP TLV; IANA is requested to make the following allocations from this registry. http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type- indicators Dhody & Wu Expires January 6, 2016 [Page 7] Internet-Draft ASSOC-ATTR July 2015 Value Name Reference TBD ATTRIBUTE-OBJECT-TLV [This I.D.] 8. Manageability Considerations 8.1. Control of Function and Policy An operator MUST BE allowed to configure the attribute associations at PCEP peers and associate it with the LSPs. 8.2. Information and Data Models [RFC7420] describes the PCEP MIB, there are no new MIB Objects for this document. 8.3. Liveness Detection and Monitoring Mechanisms defined in this document do not imply any new liveness detection and monitoring requirements in addition to those already listed in [RFC5440]. 8.4. Verify Correct Operations Mechanisms defined in this document do not imply any new operation verification requirements in addition to those already listed in [RFC5440]. 8.5. Requirements On Other Protocols Mechanisms defined in this document do not imply any new requirements on other protocols. 8.6. Impact On Network Operations Mechanisms defined in this document do not have any impact on network operations in addition to those already listed in [RFC5440]. 9. Acknowledgments A special thanks to author of [I-D.minei-pce-association-group], this document borrow some of the text from it. 10. References Dhody & Wu Expires January 6, 2016 [Page 8] Internet-Draft ASSOC-ATTR July 2015 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, August 2006. [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009. [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-01 (work in progress), July 2015. [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-11 (work in progress), April 2015. 10.2. Informative References [RFC5394] Bryskin, I., Papadimitriou, D., Berger, L., and J. Ash, "Policy-Enabled Path Computation Framework", RFC 5394, December 2008. [RFC6805] King, D. and A. Farrel, "The Application of the Path Computation Element Architecture to the Determination of a Sequence of Domains in MPLS and GMPLS", RFC 6805, November 2012. [RFC7150] Zhang, F. and A. Farrel, "Conveying Vendor-Specific Constraints in the Path Computation Element Communication Protocol", RFC 7150, March 2014. [RFC7420] Koushik, A., Stephan, E., Zhao, Q., King, D., and J. Hardwick, "Path Computation Element Communication Protocol (PCEP) Management Information Base (MIB) Module", RFC 7420, December 2014. [I-D.ietf-pce-pceps] Lopez, D., Dios, O., Wu, W., and D. Dhody, "Secure Transport for PCEP", draft-ietf-pce-pceps-04 (work in progress), May 2015. Dhody & Wu Expires January 6, 2016 [Page 9] Internet-Draft ASSOC-ATTR July 2015 Appendix A. Contributor Addresses Xian Zhang Huawei Technologies Bantian, Longgang District Shenzhen 518129 P.R.China EMail: zhang.xian@huawei.com Udayasree Palle Huawei Technologies Divyashree Techno Park, Whitefield Bangalore, Karnataka 560037 INDIA EMail: udayasree.palle@huawei.com Authors' Addresses Dhruv Dhody Huawei Technologies Divyashree Techno Park, Whitefield Bangalore, Karnataka 560037 India EMail: dhruv.ietf@gmail.com Qin Wu Huawei Technologies 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China EMail: sunseawq@huawei.com Dhody & Wu Expires January 6, 2016 [Page 10]