Networking Working GroupInternet Engineering Task Force (IETF) L. GinsbergInternet-Draft N. Akiya Intended status: Standards TrackRequest for Comments: 7883 Cisco SystemsExpires: September 3, 2015Category: Standards Track N. Akiya ISSN: 2070-1721 Big Switch Networks M. Chen HuaweiMarch 2, 2015July 2016 AdvertisingS-BFDSeamless Bidirectional Forwarding Detection (S-BFD) Discriminators in IS-ISdraft-ietf-isis-sbfd-discriminator-02.txtAbstract This document defines a means of advertising one or moreS-BFDSeamless Bidirectional Forwarding Detection (S-BFD) Discriminators using the IS-IS RouterCapabilityCAPABILITY TLV.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].Status of This Memo ThisInternet-Draftissubmitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documentsan Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF).Note that other groups may also distribute working documents as Internet-Drafts. The listIt represents the consensus ofcurrent Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents validthe IETF community. It has received public review and has been approved fora maximumpublication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 ofsix monthsRFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may beupdated, replaced, or obsoleted by other documentsobtained atany 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 3, 2015.http://www.rfc-editor.org/info/rfc7883. Copyright Notice Copyright (c)20152016 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 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. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Table of Contents 1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . 2....................................................3 2. Encoding Format. . . . . . . . . . . . . . . . . . . . . . 2.................................................3 3. IANA Considerations. . . . . . . . . . . . . . . . . . . . . 3.............................................4 4. Security Considerations. . . . . . . . . . . . . . . . . . . 3.........................................4 5.Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 6.Normative References. . . . . . . . . . . . . . . . . . . . 4............................................4 Acknowledgements ...................................................5 Authors' Addresses. . . . . . . . . . . . . . . . . . . . . . . 4.................................................5 1. Introduction[S-BFD][RFC7880] defines a simplified mechanismto usefor using Bidirectional Forwarding Detection(BFD)[RFC5880].(BFD) [RFC5880]. This mechanism depends on network nodes knowing the BFDdiscriminators whichDiscriminators that each node in the network has reserved for this purpose.UseThe use of the Intermediate System to Intermediate System(IS-IS)[IS-IS](IS-IS) [IS-IS] protocol is one possible means of advertising these discriminators. 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. Encoding Format The IS-IS Router CAPABILITY TLV as defined in [RFC4971] will be used to advertiseS-BFD discriminators.Seamless BFD (S-BFD) Discriminators. A new sub-TLV is defined as described below. S-BFD Discriminators sub-TLVs are formatted as specified in [RFC5305]. No. of octets +-----------------------------+ | Type(to be assigned by(20) | 1| IANA - suggested value 20) |+-----------------------------+ | Length (multiple of 4) | 1 +-----------------------------+ | Discriminator Value(s) | 4/Discriminator : : +-----------------------------+InclusionThe inclusion ofthean S-BFD Discriminators sub-TLV in a RouterCapabilityCAPABILITY TLV is optional. Multiple S-BFD Discriminators sub-TLVs MAY be advertised by an IS.When multiple S-BFD discriminators are advertised howHow a given discriminator is mapped to a specific use case when multiple S-BFD Discriminators are advertised is out of scope for this document. S-BFDdiscriminatorDiscriminator advertisements MAY be flooded within an area or throughout thedomaindomain, using the procedures specified in [RFC4971]. The appropriate flooding scope depends on the intended use of S-BFD. If S-BFDuseusage will be exclusively within a Level-1areaarea, then area scope is appropriate. If S-BFD usage will span differentL1 areasLevel-1 areas, then domain scope is appropriate. 3. IANA ConsiderationsThis document requires the definition ofIANA has added a new sub-TLV in theSub- TLVs"Sub-TLVs for TLV242242" registry. Thevalue written belowregistration isa suggested value subject to assignment by IANA.as follows: Value Description---- -------------------------- -------------------- 20 S-BFD Discriminators 4. Security Considerations Security concerns for IS-IS are addressed in [IS-IS], [RFC5304], and [RFC5310].Introduction of theThe new S-BFD Discriminators sub-TLVintroduces nodoes not introduce any new security risks for IS-IS.Advertisement ofAdvertising the S-BFDdiscriminators does makeDiscriminators makes it possible for attackers to initiate S-BFD sessions using the advertised information. The vulnerabilities this poses and how to mitigate them are discussed inthe Security Considerations section of [S-BFD].[RFC7880]. 5.Acknowledgements The authors wish to thank Sam Aldrin, Manav Bhatia, and Carlos Pignataro for input essential to defining the needed functionality. 6.Normative References [IS-IS] International Organization for Standardization, "IntermediatesystemSystem to IntermediatesystemSystem intra-domain routeing information exchange protocol for use in conjunction with the protocol for providing the connectionless-modeNetwork Servicenetwork service (ISO8473), ISO/IEC 10589:2002, Second Edition.", Nov8473)", ISO Standard 10589, 2002. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March1997.1997, <http://www.rfc-editor.org/info/rfc2119>. [RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed., "Intermediate System to Intermediate System (IS-IS) Extensions for Advertising Router Information", RFC 4971, DOI 10.17487/RFC4971, July2007.2007, <http://www.rfc-editor.org/info/rfc4971>. [RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic Authentication", RFC 5304, DOI 10.17487/RFC5304, October2008.2008, <http://www.rfc-editor.org/info/rfc5304>. [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, DOI 10.17487/RFC5305, October2008.2008, <http://www.rfc-editor.org/info/rfc5305>. [RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R., and M. Fanto, "IS-IS Generic Cryptographic Authentication", RFC 5310, DOI 10.17487/RFC5310, February2009.2009, <http://www.rfc-editor.org/info/rfc5310>. [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD)", RFC 5880, DOI 10.17487/RFC5880, June2010. [S-BFD]2010, <http://www.rfc-editor.org/info/rfc5880>. [RFC7880] Pignataro, C., Ward, D., Akiya, N., Bhatia, M., and S. Pallagatti, "Seamless Bidirectional Forwarding Detection(S-BFD), draft-ietf-bfd-seamless-base-04(work in progress)", January 2015.(S-BFD)", RFC 7880, DOI 10.17487/RFC7880, July 2016, <http://www.rfc-editor.org/info/rfc7880>. Acknowledgements The authors wish to thank Sam Aldrin, Manav Bhatia, and Carlos Pignataro for input essential to defining the needed functionality. Authors' Addresses Les Ginsberg Cisco Systems 510 McCarthy Blvd. Milpitas, CA 95035USAUnited States of America Email: ginsberg@cisco.com Nobo AkiyaCisco SystemsBig Switch Networks Email:nobo@cisco.comnobo.akiya.dev@gmail.com Mach(Guoyi) Chen Huawei Email: mach.chen@huawei.com