PCE Working Group D. Dhody Internet-Draft Q. Wu Intended status: Standards Track Huawei Technologies Expires: September 13, 2017 March 12, 2017 Path Computation Element communication Protocol extension for relationship between LSPs and Attributes draft-dhody-pce-association-attr-06 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). 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 September 13, 2017. Copyright Notice Copyright (c) 2017 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 September 13, 2017 [Page 1] Internet-Draft ASSOC-ATTR March 2017 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 . . . . . . . . . . . . . . . . . . . . 4 3.2. Bundled requests . . . . . . . . . . . . . . . . . . . . 4 4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5. Attribute Association Group . . . . . . . . . . . . . . . . . 5 5.1. ATTRIBUTE-OBJECT-TLV . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 7.1. Association object Type Indicators . . . . . . . . . . . 8 7.2. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 8 7.3. Flag field in ATTRIBUTE-OBJECT-TLV . . . . . . . . . . . 8 8. Manageability Considerations . . . . . . . . . . . . . . . . 8 8.1. Control of Function and Policy . . . . . . . . . . . . . 9 8.2. Information and Data Models . . . . . . . . . . . . . . . 9 8.3. Liveness Detection and Monitoring . . . . . . . . . . . . 9 8.4. Verify Correct Operations . . . . . . . . . . . . . . . . 9 8.5. Requirements On Other Protocols . . . . . . . . . . . . . 9 8.6. Impact On Network Operations . . . . . . . . . . . . . . 9 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 10.1. Normative References . . . . . . . . . . . . . . . . . . 9 10.2. Informative References . . . . . . . . . . . . . . . . . 10 Appendix A. Policy . . . . . . . . . . . . . . . . . . . . . . . 12 Appendix B. Contributor Addresses . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 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.ietf-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) and is equally applicable to the active and passive modes of a stateful PCE and a stateless PCE. Dhody & Wu Expires September 13, 2017 [Page 2] Internet-Draft ASSOC-ATTR March 2017 This document specifies a PCEP extension to associate one or more LSPs with a set of attributes. PCEP Extensions for Stateful PCE Model [I-D.ietf-pce-stateful-pce] describes a set of extensions to PCEP to enable active control of MPLS-TE and GMPLS tunnels. [I-D.ietf-pce-pce-initiated-lsp] describes the setup and teardown of PCE-initiated LSPs under the active stateful PCE model, without the need for local configuration on the PCC, thus allowing for a dynamic network. The mechanism described in this document is equally applicable to these deployment models. 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: Multi-protocol Label Switching. PAG: Policy Association Group. 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 - Dhody & Wu Expires September 13, 2017 [Page 3] Internet-Draft ASSOC-ATTR March 2017 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. This can also be used for tagging bunch of LSP to a particular customer or for creation of virtual network like in case of Abstraction and Control of TE Networks (ACTN) [I-D.ietf-teas-actn-requirements]. (See [I-D.leedhody-pce-vn-association]) 3.2. 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.ietf-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). A new optional Association Object-type is defined based on the generic Association object - o Attribute Association Group (AAG) Thus this document defines a new association type called "Attribute Association Type" of value TBD1. 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.ietf-pce-association-group]. Dhody & Wu Expires September 13, 2017 [Page 4] Internet-Draft ASSOC-ATTR March 2017 One or more LSP are grouped via a single group identifier as defined in [I-D.ietf-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 September 13, 2017 [Page 5] Internet-Draft ASSOC-ATTR March 2017 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 | Flags |R| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Association type (TBD1) | 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | Flags |R| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Association type (TBD1) | Association ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | IPv6 Association Source | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // Optional TLVs // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: The AAG Object formats Type = TBD1 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 behavioral information, described in [RFC7470]. 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 September 13, 2017 [Page 6] Internet-Draft ASSOC-ATTR March 2017 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 (TBD2) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags |M|R| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Object-Class | OT |Res|P|I| Object Length (bytes) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // (Object body) // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: ATTRIBUTE-OBJECT-TLV format The type of the TLV is TBD2 and it has a variable length. The value part consist of a 32-bit Flag filed followed by a PCEP object (including common header [RFC5440] identifying the object) that is associated with this AAG. Following Flags are defined: R (Remove - 1 bit): This is set to indicate that the attribute is being removed from the attribute-list. M (Modify - 1 bit): This is set to indicate that a previous attribute is being modified, and the peer should overwrite the attribute with the new value as per the object-body. 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 with no ATTRIBUTE-OBJECT-TLV. 6. Security Considerations This document defines a new types 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.ietf-pce-association-group] in itself. Some deployments may find the associations and their implications as extra sensitive and thus should employ suitable PCEP security mechanisms like TCP-AO or [I-D.ietf-pce-pceps]. Dhody & Wu Expires September 13, 2017 [Page 7] Internet-Draft ASSOC-ATTR March 2017 7. IANA Considerations 7.1. Association object Type Indicators This document defines the following new association type originally defined in [I-D.ietf-pce-association-group]. Value Name Reference TBD1 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 Value Name Reference TBD2 ATTRIBUTE-OBJECT-TLV [This I.D.] 7.3. Flag field in ATTRIBUTE-OBJECT-TLV This document requests that a new sub-registry, named "ATTRIBUTE- OBJECT-TLV Flag Field", is created within the "Path Computation Element Protocol (PCEP) Numbers" registry to manage the Flag field of the ATTRIBUTE-OBJECT-TLV. New values are to be assigned by Standards Action [RFC5226]. Each bit should be tracked with the following qualities: o Bit number (counting from bit 0 as the most significant bit) o Capability description o Defining RFC The following values are defined in this document: Bit Description Reference 31 Remove [This I.D.] 30 Modify [This I.D.] 8. Manageability Considerations Dhody & Wu Expires September 13, 2017 [Page 8] Internet-Draft ASSOC-ATTR March 2017 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.ietf-pce-association-group], this document borrow some of the text from it. 10. References 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . Dhody & Wu Expires September 13, 2017 [Page 9] Internet-Draft ASSOC-ATTR March 2017 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, DOI 10.17487/RFC5440, March 2009, . [RFC7470] Zhang, F. and A. Farrel, "Conveying Vendor-Specific Constraints in the Path Computation Element Communication Protocol", RFC 7470, DOI 10.17487/RFC7470, March 2015, . [I-D.ietf-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- ietf-pce-association-group-02 (work in progress), January 2017. [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-18 (work in progress), December 2016. 10.2. Informative References [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, DOI 10.17487/RFC4655, August 2006, . [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, DOI 10.17487/RFC5226, May 2008, . [RFC6805] King, D., Ed. and A. Farrel, Ed., "The Application of the Path Computation Element Architecture to the Determination of a Sequence of Domains in MPLS and GMPLS", RFC 6805, DOI 10.17487/RFC6805, November 2012, . [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, DOI 10.17487/RFC7420, December 2014, . Dhody & Wu Expires September 13, 2017 [Page 10] Internet-Draft ASSOC-ATTR March 2017 [I-D.ietf-pce-pceps] Lopez, D., Dios, O., Wu, W., and D. Dhody, "Secure Transport for PCEP", draft-ietf-pce-pceps-11 (work in progress), January 2017. [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-09 (work in progress), March 2017. [I-D.ietf-teas-actn-requirements] Lee, Y., Dhody, D., Belotti, S., Pithewan, K., and D. Ceccarelli, "Requirements for Abstraction and Control of TE Networks", draft-ietf-teas-actn-requirements-04 (work in progress), January 2017. [I-D.ietf-pce-association-policy] Dhody, D., Sivabalan, S., Litkowski, S., Tantsura, J., and J. Hardwick, "Path Computation Element communication Protocol extension for associating Policies and LSPs", draft-ietf-pce-association-policy-00 (work in progress), December 2016. [I-D.leedhody-pce-vn-association] Lee, Y., Dhody, D., Zhang, X., and D. Ceccarelli, "PCEP Extensions for Establishing Relationships Between Sets of LSPs and Virtual Networks", draft-leedhody-pce-vn- association-01 (work in progress), October 2016. Dhody & Wu Expires September 13, 2017 [Page 11] Internet-Draft ASSOC-ATTR March 2017 Appendix A. Policy An earlier version of this document also had details about Policy association group. This has been moved to an independent document - [I-D.ietf-pce-association-policy]. Appendix B. 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 560066 India EMail: udayasree.palle@huawei.com Authors' Addresses Dhruv Dhody Huawei Technologies Divyashree Techno Park, Whitefield Bangalore, Karnataka 560066 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 September 13, 2017 [Page 12]