Network Working Group X. Xu Internet-Draft Huawei Intended status: Standards Track U. Chunduri Expires: March 29, 2015 Ericsson September 25, 2014 Carrying Routable IP Addresses in IS-IS Router Capability TLV draft-xu-isis-routable-ip-address-01 Abstract This document proposes two new sub-TLVs of the IS-IS Router CAPABILITY TLV, called routable IPv4 address sub-TLV and routable IPv6 address sub-TLV respectively. 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 March 29, 2015. Copyright Notice Copyright (c) 2014 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. Xu & Chunduri Expires March 29, 2015 [Page 1] Internet-Draft September 2014 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Routable IPv4 Address Sub-TLV . . . . . . . . . . . . . . . . 3 4. Routable IPv6 Address Sub-TLV . . . . . . . . . . . . . . . . 3 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 7. Security Considerations . . . . . . . . . . . . . . . . . . . 4 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 8.1. Normative References . . . . . . . . . . . . . . . . . . 4 8.2. Informative References . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction There are several situations where it is useful for IS-IS routers within a given area to identify the routable IP address of IS-IS routers within the same area. In deployments, multiple IP addresses can be hosted by an IS-IS router for a particular purpose and all these addresses cannot be represented through the currently defined TE Router ID TLVs [RFC5305] [RFC6119]. For example, a private address range used for PQ nodes, as specified in Section 12 of [I-D.ietf-rtgwg-remote-lfa], can be easily represented through the sub-TLVs defined in this document without having to parse through all TE reachability TLVs [RFC5305] [RFC5120] where a receiving node can not identify if the prefix is an external prefix, an inter-area leaked prefix or a locally attached prefix. Similarly, in the case where a topology database is learned by an orchestrator or controller [I-D.ietf-i2rs-problem-statement], an application can easily determine the router reachability from a private address range (specifically for this purpose), advertised through the sub-TLVs defined in this document. Meanwhile, there are also several situations where it is required for IS-IS routers in one area to find correlations between routable IP addresses and capabilities of IS-IS routers in another area. One example is the Entropy Label Capability (ELC) advertisement [I-D.xu-isis-mpls-elc] across the IS-IS domain. In this example, assume the ELC TLV originated by a router in one area is propagated to another area, those routers in the latter area need to find routable IP addresses of the router originating that ELC TLV before inserting the Entropy Label (EL) for packets going to the Label Switch Path (LSP) tunnel towards one of the above routable IP addresses. Another example is the S-BFD discriminator distribution [I-D.ginsberg-isis-sbfd-discriminator] across the IS-IS domain. In this example, assume the S-BFD Discriminator sub-TLV originated by a Xu & Chunduri Expires March 29, 2015 [Page 2] Internet-Draft September 2014 router in one area is propagated to another area, those routers in the latter area need to find routable IP addresses of the router originating that S-BFD Discriminator sub-TLV so as to set up S-BDF sessions with that originating router. However, in the IS-IS Router CAPABILITY TLV as defined in [RFC4971], which is applicable for both IPv4 IS-IS [RFC1195] [RFC5305] and IPv6 MT IS-IS [RFC5120], there is no such field for containing the routable IP address. Although TE Router ID sub-TLVs defined in [RFC5316] can be used to carry routable IP addresses, TE Router ID sub-TLVs are specifically designed for TE purpose. Therefore, this document propose two new sub-TLVs of this CAPABILITY TLV to carry a routable IPv4 and IPv6 address of the router originating the CAPABILITY TLV respectively. These two sub-TLVs could be used for non-TE purpose. A router MUST NOT advertise the sub-TLVs defined in this document if the same has been advertised through TE Router ID sub-TLVs. 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]. 2. Terminology This memo makes use of the terms defined in [RFC4971]. 3. Routable IPv4 Address Sub-TLV A new sub-TLV of the IS-IS Router Capability TLV, called Routable IPv4 Address sub-TLV is defined to carry one or more routable /32 IPv4 address of the router originating the CAPABILITY TLV. The Type of this sub-TLV is TBD, the Length is variable (multiple of 4), and the Value field contains one or more routable IPv4 address of the router originating the CAPABILITY TLV. For every IPv4 address of this type, a corresponding IP reachability TLV [RFC5305] or MT IP reachability TLV [RFC5120] MUST be included in its LSP. An implementation receiving a Routable IPv4 Address sub-TLV defined in this document MUST NOT consider these /32 reachable prefixes in the standard SPF calculation because this can lead to forwarding loops when interacting with systems that do not support this TLV. 4. Routable IPv6 Address Sub-TLV A new sub-TLV of the IS-IS Router Capability TLV, called Routable IPv6 Address sub-TLV is defined to carry one or more routable /128 IPv6 global address of the router originating the CAPABILITY TLV. Xu & Chunduri Expires March 29, 2015 [Page 3] Internet-Draft September 2014 The Type of this sub-TLV is TBD, the Length is variable (multiple of 16), and the Value field contains one or more routable IPv6 global address of the router originating the CAPABILITY TLV. For every IPv6 address of this type,a corresponding IPv6 reachability TLV [RFC5308] orMT IPv6 reachability TLV [RFC5120] MUST be included in its LSP. An implementation receiving a Routable IPv6 Address sub-TLV defined in this document MUST NOT consider these /128 reachable prefixes in the standard SPF calculation because this can lead to forwarding loops when interacting with systems that do not support this TLV. 5. Acknowledgements Thanks Karsten Thomann, Anton Smirnov, Joel Jaeggli, Joel M. Halpern, Wes George and Acee Lindem for their valuable comments on the initial idea of this draft. 6. IANA Considerations This memo includes a request to IANA to allocate two sub-TLV type codes within the IS-IS Router Capability TLV for the Routable IPv4 Address Sub-TLV and the Routable IPv6 Address Sub-TLV respectively. 7. Security Considerations This document does not introduce any new security risk. 8. References 8.1. 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. 8.2. Informative References [I-D.ginsberg-isis-sbfd-discriminator] Ginsberg, L., Akiya, N., and M. Chen, "Advertising S-BFD Discriminators in IS-IS", draft-ginsberg-isis-sbfd- discriminator-00 (work in progress), May 2014. [I-D.ietf-i2rs-problem-statement] Atlas, A., Nadeau, T., and D. Ward, "Interface to the Routing System Problem Statement", draft-ietf-i2rs- problem-statement-04 (work in progress), June 2014. Xu & Chunduri Expires March 29, 2015 [Page 4] Internet-Draft September 2014 [I-D.ietf-rtgwg-remote-lfa] Bryant, S., Filsfils, C., Previdi, S., Shand, M., and S. Ning, "Remote LFA FRR", draft-ietf-rtgwg-remote-lfa-06 (work in progress), May 2014. [I-D.xu-isis-mpls-elc] Xu, X., Kini, S., Sivabalan, S., and C. Filsfils, "Signaling Entropy Label Capability Using IS-IS", draft- xu-isis-mpls-elc-00 (work in progress), December 2013. [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and dual environments", RFC 1195, December 1990. [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi Topology (MT) Routing in Intermediate System to Intermediate Systems (IS-ISs)", RFC 5120, February 2008. [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, October 2008. [RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308, October 2008. [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in Support of Inter-Autonomous System (AS) MPLS and GMPLS Traffic Engineering", RFC 5316, December 2008. [RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic Engineering in IS-IS", RFC 6119, February 2011. Authors' Addresses Xiaohu Xu Huawei Email: xuxiaohu@huawei.com Uma Chunduri Ericsson Email: uma.chunduri@ericsson.com Xu & Chunduri Expires March 29, 2015 [Page 5]