Conveying Vendor-Specific Information in the Path Computation Element (PCE) Communication Protocol (PCEP) extensions for stateful PCE.
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|Authors||Cheng Li , Haomian Zheng|
|Last updated||2019-02-19 (Latest revision 2018-08-29)|
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PCE Working Group C. Li Internet-Draft H. Zheng Intended status: Standards Track Huawei Technologies Expires: August 23, 2019 February 19, 2019 Conveying Vendor-Specific Information in the Path Computation Element (PCE) Communication Protocol (PCEP) extensions for stateful PCE. draft-dhody-pce-stateful-pce-vendor-06 Abstract A Stateful Path Computation Element (PCE) maintains information on the current network state, including: computed Label Switched Path (LSPs), reserved resources within the network, and pending path computation requests. This information may then be considered when computing new traffic engineered LSPs, and for associated and dependent LSPs, received from Path Computation Clients (PCCs). RFC 7470 defines a facility to carry vendor-specific information in PCEP. This document extends this capability for the stateful PCE model. 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 https://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 August 23, 2019. Copyright Notice Copyright (c) 2019 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 Li & Zheng Expires August 23, 2019 [Page 1] Internet-Draft VENDOR-STATEFUL February 2019 (https://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 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Procedures for the Vendor Information Object . . . . . . . . 3 3. Procedures for the Vendor Information TLV . . . . . . . . . . 5 4. Vendor Information Object and TLV . . . . . . . . . . . . . . 5 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 8.1. Normative References . . . . . . . . . . . . . . . . . . 6 8.2. Informative References . . . . . . . . . . . . . . . . . 7 Appendix A. Contributor Addresses . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction The Path Computation Element communication Protocol (PCEP) [RFC5440] provides mechanisms for Path Computation Elements (PCEs) to perform path computations in response to Path Computation Clients' (PCCs) requests. A stateful PCE is capable of considering, for the purposes of path computation, not only the network state in terms of links and nodes (referred to as the Traffic Engineering Database or TED) but also the status of active services (previously computed paths, and currently reserved resources, stored in the Label Switched Paths Database (LSPDB). [RFC8051] describes general considerations for a stateful PCE deployment and examines its applicability and benefits, as well as its challenges and limitations through a number of use cases. [RFC8231] describes a set of extensions to PCEP to provide stateful control. A stateful PCE has access to not only the information carried by the network's Interior Gateway Protocol (IGP), but also the set of active paths and their reserved resources for its computations. The additional state allows the PCE to compute constrained paths while considering individual LSPs and their interactions. [RFC8281] describes the setup, maintenance and Li & Zheng Expires August 23, 2019 [Page 2] Internet-Draft VENDOR-STATEFUL February 2019 teardown of PCE-initiated LSPs under the stateful PCE model. These extensions added new messages in PCEP. [RFC7470] defined Vendor Information object that can be used to carry arbitrary, proprietary information such as vendor-specific constraints. It also defined VENDOR-INFORMATION-TLV that can be used to carry arbitrary information within any existing or future PCEP object that supports TLVs. This document extend the usage of Vendor Information Object and VENDOR-INFORMATION-TLV to stateful PCE. The VENDOR-INFORMATION-TLV can be carried inside any of the new objects added in PCEP for stateful PCE as per [RFC7470], this document extend the PCEP messages to also include the Vendor Information Object too. 1.1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 2. Procedures for the Vendor Information Object A Path Computation LSP State Report message [RFC8231] (also referred to as PCRpt message) is a PCEP message sent by a PCC to a PCE to report the current state of an LSP. A PCC that wants to convey proprietary or vendor-specific information or metrics to a PCE does so by including a Vendor Information object in the PCRpt message. The contents and format of the object are described in Section 4 of [RFC7470]. The PCE determines how to interpret the information in the Vendor Information object by examining the Enterprise Number it contains. The Vendor Information object is OPTIONAL in a PCRpt message. Multiple instances of the object MAY be used on a single PCRpt message. Different instances of the object can have different Enterprise Numbers. The format of the PCRpt message (with [RFC8231] as base) is updated as follows Li & Zheng Expires August 23, 2019 [Page 3] Internet-Draft VENDOR-STATEFUL February 2019 <PCRpt Message> ::= <Common Header> <state-report-list> Where: <state-report-list> ::= <state-report>[<state-report-list>] <state-report> ::= [<SRP>] <LSP> <path> [<vendor-info-list>] Where: <vendor-info-list> ::= <VENDOR-INFORMATION> [<vendor-info-list>] <path> is defined in [RFC8231]. A Path Computation LSP Update Request message (also referred to as PCUpd message) is a PCEP message sent by a PCE to a PCC to update attributes of an LSP. The Vendor Information object can be included in a PCUpd message to convey proprietary or vendor-specific information. The format of the PCUpd message (with [RFC8231] as base) is updated as follows <PCUpd Message> ::= <Common Header> <update-request-list> Where: <update-request-list> ::= <update-request> [<update-request-list>] <update-request> ::= <SRP> <LSP> <path> [<vendor-info-list>] Where: <vendor-info-list> ::= <VENDOR-INFORMATION> [<vendor-info-list>] <path> is defined in [RFC8231]. A Path Computation LSP Initiate Message (also referred to as PCInitiate message) is a PCEP message sent by a PCE to a PCC to trigger LSP instantiation or deletion. The Vendor Information object can be included in a PCInitiate message to convey proprietary or vendor-specific information. Li & Zheng Expires August 23, 2019 [Page 4] Internet-Draft VENDOR-STATEFUL February 2019 The format of the PCInitiate message (with [RFC8281] as base) is updated as follows <PCInitiate Message> ::= <Common Header> <PCE-initiated-lsp-list> Where: <PCE-initiated-lsp-list> ::= <PCE-initiated-lsp-request> [<PCE-initiated-lsp-list>] <PCE-initiated-lsp-request> ::= (<PCE-initiated-lsp-instantiation>| <PCE-initiated-lsp-deletion>) <PCE-initiated-lsp-instantiation> ::= <SRP> <LSP> [<END-POINTS>] <ERO> [<attribute-list>] [<vendor-info-list>] Where: <vendor-info-list> ::= <VENDOR-INFORMATION> [<vendor-info-list>] <PCE-initiated-lsp-deletion> and <attribute-list> is as per [RFC8281]. A legacy implementation that does not recognize the Vendor Information object will act according to the procedures set out in [RFC8231] and [RFC8281]. An implementation that supports the Vendor Information object, but receives one carrying an Enterprise Number that it does not support, SHOULD ignore the object as per [RFC7470]. 3. Procedures for the Vendor Information TLV The Vendor Information TLV can be used to carry vendor-specific information that applies to a specific PCEP object by including the TLV in the object. This includes objects used in stateful PCE extension such as SRP and LSP object. All the procedures as per section 3 of [RFC7470]. 4. Vendor Information Object and TLV [RFC7470] specify the format of VENDOR-INFORMATION Object and VENDOR- INFORMATION-TLV. Li & Zheng Expires August 23, 2019 [Page 5] Internet-Draft VENDOR-STATEFUL February 2019 5. IANA Considerations There are no IANA consideration in this document. 6. Security Considerations The protocol extensions defined in this document do not change the nature of PCEP. Therefore, the security considerations set out in [RFC5440], [RFC7470], [RFC8231] and [RFC8281] apply unchanged. As stated in [RFC6952], PCEP implementations SHOULD support the TCP- AO [RFC5925] and not use TCP MD5 because of TCP MD5's known vulnerabilities and weakness. PCEP also support Transport Layer Security (TLS) [RFC8253] as per the recommendations and best current practices in [RFC7525]. 7. Acknowledgments Thanks to Avantika, Mahendra Singh Negi, Udayasree Palle and Swapna K for their suggestions. 8. References 8.1. 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, <https://www.rfc-editor.org/info/rfc2119>. [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, DOI 10.17487/RFC5440, March 2009, <https://www.rfc-editor.org/info/rfc5440>. [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, <https://www.rfc-editor.org/info/rfc7470>. [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>. Li & Zheng Expires August 23, 2019 [Page 6] Internet-Draft VENDOR-STATEFUL February 2019 [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path Computation Element Communication Protocol (PCEP) Extensions for Stateful PCE", RFC 8231, DOI 10.17487/RFC8231, September 2017, <https://www.rfc-editor.org/info/rfc8231>. [RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path Computation Element Communication Protocol (PCEP) Extensions for PCE-Initiated LSP Setup in a Stateful PCE Model", RFC 8281, DOI 10.17487/RFC8281, December 2017, <https://www.rfc-editor.org/info/rfc8281>. 8.2. Informative References [RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP Authentication Option", RFC 5925, DOI 10.17487/RFC5925, June 2010, <https://www.rfc-editor.org/info/rfc5925>. [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of BGP, LDP, PCEP, and MSDP Issues According to the Keying and Authentication for Routing Protocols (KARP) Design Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, <https://www.rfc-editor.org/info/rfc6952>. [RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, "Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May 2015, <https://www.rfc-editor.org/info/rfc7525>. [RFC8051] Zhang, X., Ed. and I. Minei, Ed., "Applicability of a Stateful Path Computation Element (PCE)", RFC 8051, DOI 10.17487/RFC8051, January 2017, <https://www.rfc-editor.org/info/rfc8051>. [RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody, "PCEPS: Usage of TLS to Provide a Secure Transport for the Path Computation Element Communication Protocol (PCEP)", RFC 8253, DOI 10.17487/RFC8253, October 2017, <https://www.rfc-editor.org/info/rfc8253>. Appendix A. Contributor Addresses Dhruv Dhody Huawei Technologies Divyashree Techno Park, Whitefield Bangalore, Karnataka 560066 India Li & Zheng Expires August 23, 2019 [Page 7] Internet-Draft VENDOR-STATEFUL February 2019 Authors' Addresses Cheng Li Huawei Technologies Huawei Campus, No. 156 Beiqing Rd. Beijing 100095 China Email: firstname.lastname@example.org Haomian Zheng Huawei Technologies F3 RnD Center, Huawei Industrial Base, Bantian, Longgang District Shenzhen, Guangdong 518129 P.R.China Email: email@example.com Li & Zheng Expires August 23, 2019 [Page 8]