Network Working Group X. Xu Internet-Draft N. Wu Intended status: Standards Track Huawei Expires: December 5, 2015 H. Shah Ciena L. Contreras Telefonica I+D June 3, 2015 Advertising Service Functions Using IS-IS draft-xu-isis-service-function-adv-03 Abstract Source Packet Routing in Networking (SPRING) WG specifies a special MPLS-based source routing mechanism, called MPLS-SPRING. Such source routing mechanism can be leveraged to realize the service path layer functionality of service function chaining (i.e, steering traffic through a particular service function path) by encoding the service function path information as an explicit path information in the form of an MPLS label stack. This document describes how to advertise service functions and their corresponding attributes (e.g.,segment ID) using IS-IS. 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 December 5, 2015. Copyright Notice Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved. Xu, et al. Expires December 5, 2015 [Page 1] Internet-Draft Advertising Service Functions Using IS-IS June 2015 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 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Advertising Service Functions and Corresponding SIDs . . . . 3 3.1. Service Function Sub-TLV . . . . . . . . . . . . . . . . 3 3.2. SF SID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 4 4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 7.1. Normative References . . . . . . . . . . . . . . . . . . 4 7.2. Informative References . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction [I-D.xu-sfc-using-mpls-spring] describes how to leverage MPLS-SPRING [I-D.ietf-spring-segment-routing-mpls]) (a.k.a., an MPLS-based source routing mechanism) to realize the service path layer functionality of the Service Function Chaining (SFC), i.e, steering traffic through the Service Function Path (SFP). To allow a service classifier to attach the segment list (i.e., an MPLS label stack) which represents a particular SFP to the selected traffic, the service classifier needs to know on which Service Function Forwarder (SFF) a given Service Function (SF) is located and what segment ID (SID) is used to indicate that SF. This document describes how to advertise Service Functions (SFs) and their corresponding attributes (e.g.,SID) using IS-IS. 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]. Xu, et al. Expires December 5, 2015 [Page 2] Internet-Draft Advertising Service Functions Using IS-IS June 2015 2. Terminology This memo makes use of the terms defined in [RFC4971], [I-D.ietf-sfc-architecture] and [I-D.xu-sfc-using-mpls-spring]. 3. Advertising Service Functions and Corresponding SIDs SFFs within the SFC domain need to advertise each SF they are offering by using a new sub-TLV of the IS-IS Router CAPABILITY TLV [RFC4971]. This new sub-TLV is called as Service Function sub-TLV. The Service Function sub-TLV could appear multiple times wihin a given IS-IS Router CAPABILITY TLV when more than one SF needs to be advertised. The scope of the advertisement depends on the application but it is recommended that it SHOULD be domain-wide. Furthermore, SFFs need to allocate a corresponding SID to each SF they are offering and advertise it by using a sub-TLV of the above Service Function sub-TLV, called SF SID sub-TLV. To support the approach of encoding SFP information in the form of an MPLS label stack as described in [I-D.xu-sfc-using-mpls-spring], SFFs SHOULD allocate a locally significant MPLS label to each SF they are offering. 3.1. Service Function Sub-TLV 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Service Function Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Sub-TLVs ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: TBD. Length: variable. Service Function Identifier: A unique identifier that represents an SF within an SFC-enabled domain. Sub-TLVs: contains zero or more sub-TLVs corresponding to the particular attributes of a given SF. The SF SID sub-TLV as defined in Section 3.2 is one such sub-TLV which is used to indicate the corrresponding SF SID. Other sub-TLVs are to be defined in the future. Xu, et al. Expires December 5, 2015 [Page 3] Internet-Draft Advertising Service Functions Using IS-IS June 2015 3.2. SF SID Sub-TLV 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Resv | SF SID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: TBD. Length: 3. Value: The rightmost 20 bits represent an MPLS label which is the SF SID of the corresponding SF. 4. Acknowledgements TBD. 5. IANA Considerations This document includes a request to IANA for allocating type codes for the Service Function sub-TLV and the SF SID sub-TLV. 6. Security Considerations This document does not introduce any new security risk. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4971] Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate System to Intermediate System (IS-IS) Extensions for Advertising Router Information", RFC 4971, July 2007. 7.2. Informative References [I-D.ietf-sfc-architecture] Halpern, J. and C. Pignataro, "Service Function Chaining (SFC) Architecture", draft-ietf-sfc-architecture-08 (work in progress), May 2015. Xu, et al. Expires December 5, 2015 [Page 4] Internet-Draft Advertising Service Functions Using IS-IS June 2015 [I-D.ietf-spring-segment-routing-mpls] Filsfils, C., Previdi, S., Bashandy, A., Decraene, B., Litkowski, S., Horneffer, M., Shakir, R., Tantsura, J., and E. Crabbe, "Segment Routing with MPLS data plane", draft-ietf-spring-segment-routing-mpls-01 (work in progress), May 2015. [I-D.xu-sfc-using-mpls-spring] Xu, X., Li, Z., Shah, H., and L. Contreras, "Service Function Chaining Using MPLS-SPRING", draft-xu-sfc-using- mpls-spring-03 (work in progress), March 2015. Authors' Addresses Xiaohu Xu Huawei Email: xuxiaohu@huawei.com Nan Wu Huawei Email: eric.wu@huawei.com Himanshu Shah Ciena Email: hshah@ciena.com Luis M. Contreras Telefonica I+D Ronda de la Comunicacion, s/n Sur-3 building, 3rd floor Madrid, 28050 Spain Email: luismiguel.contrerasmurillo@telefonica.com URI: http://people.tid.es/LuisM.Contreras/ Xu, et al. Expires December 5, 2015 [Page 5]