Network Working Group Rahul Aggarwal Internet Draft Kireeti Kompella Expiration Date:
October 2004January 2005 Juniper Networks Advertising a Router's Local Addresses in OSPF TE Extensions draft-ietf-ospf-te-node-addr-00.txt 1.draft-ietf-ospf-te-node-addr-01.txt Status of this Memo This document is an Internet-DraftBy submitting this Internet-Draft, I certify that any applicable patent or IPR claims of which I am aware have been disclosed, and isany of which I become aware will be disclosed, in full conformanceaccordance with all provisions of Section 10 of RFC2026.RFC 3668. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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.'' The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. 2.Abstract This document describes procedures that enhance OSPF Traffic Engineering (TE) extensions for advertising a router's local addresses. This is needed to enable other routers in a network to compute traffic engineered MPLS LSPs to a given router's local addresses. Currently, the only addresses belonging to a router that are advertised in TE LSAs are the local addresses corresponding to TE enabled links and the local address corresponding to the Router ID. 3.1. Motivation In some cases it is desirable to setup constrained shortest path first (CSPF) computed MPLS TE LSPs to local addresses of a router, that are not currently advertised in the TE LSAs i.e. loopback and non-TE interface addresses. For instance, in a network carrying VPN and non-VPN traffic, it is often desirable to use different MPLS TE LSPs for the VPN traffic and the non-VPN traffic. In this case one loopback address may be used as the BGP next-hop for VPN traffic while another may be used as the BGP next-hop for non-VPN traffic. It is also possible that different BGP sessions are used for VPN and non-VPN services. Hence two separate MPLS TE LSPs are desirable, one to each loopback address. However currently routers in an OSPF network can only use CSPF to compute MPLS TE LSPs to the router ID or the local addresses of TE enabled links of a remote router. This restriction arises because OSPF TE extensions [OSPF-TE, OSPFv3-TE] only advertise the router ID and the local addresses of TE enabled links of a given router. Other routers in the network can populate their traffic engineering database (TED) with these local addresses belonging to the advertising router. However they cannot populate the TED with other local addresses of the advertising router i.e. loopback and non-TE interface addresses. OSPFv2 stub links in the router LSA [OSPFv2], provide stub reachability information to the router but are not sufficient to learn all the local addresses of a router. In particular for a subnetted point-to-point (P2P) interface the stub link ID is the subnet address, while for a non-subnetted interface the stub link ID is the neighbor address. Intra-prefix LSAs in OSPFv3 [OSPFv3] are also not sufficient to learn the local addresses. For the above reasons this document proposes an enhancement to OSPF TE extensions to advertise the local addresses of a node. 4.2. A Potential Solution A potential solution would be to advertise a TE link TLV for each local address, possibly with a new link type. However, this is inefficient since the only meaningful information is the address. Furthermore, this would require implementations to process these TE link TLVs differently from others; for example, the TE metric is normally considered a mandatory sub-TLV, but would have no meaning for a local address. 5.3. Proposed Solution The proposed solution is to advertise the local addresses of a router in a new OSPF TE LSA node attribute TLV. node attribute TLV. It is anticipated that a node attribute TLV will also prove more generally useful. 220.127.116.11. Node Attribute TLV The node attribute TLV carries the attributes associated with a router. The TLV type is TBD and the length is variable. It contains one or more sub-TLVs. This document defines the following sub-TLVs: 1. Node IPv4 Local Address sub-TLV 2. Node IPv6 Local Address sub-TLV The node IPv4 local address sub-TLV has a type of 1 and contains one or more local IPv4 addresses. It has the following format: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Address 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Address n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The length is set to 4 * n where n is the number of local addresses included in the sub-TLV. The node IPv6 local address sub-TLV has a type of 2 and contains one or more local IPv6 addresses. It has the following format: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 2 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 Address 1 | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 Address n | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-- The length is set to 16 * n where n is the number of local addresses included in the sub-TLV. 18.104.22.168. Operation A router announces one or more local addresses in the node attribute TLV. The local addresses that can be learned from TE LSAs i.e. router address and TE interface addresses should not be advertised in the node local address sub-TLV. The local addresses advertised will depend on the local configuration of the advertising router. The default behavior may be to advertise all the loopback interface addresses. 6.4. Security Considerations This document does not introduce any further security issues other than those discussed in [OSPF-TE, OSPFv3-TE]. 7.5. IANA Considerations The Node Attribute TLV type has to be IANA assigned from the range 3 - 32767 as specified in [OSPF-TE]. 8.6. Acknowledgments We would like to thank Nischal Sheth for his contribution to this work. We woud also like to thank Jean Philippe Vasseur, Acee Lindem, Venkata Naidu and Dimitri Papadimitriou for their comments. 9.7. References 7.1. Normative References [OSPF] Moy, J., "OSPF Version 2", RFC 2328, April 1998. [RFC] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [OSPF-TE] D. Katz, K. Kompella, D. Yeung, "Traffic Engineering Extensions to OSPF version 2", RFC 3630, September 2003. [OSPFv3] R. Coltun, D. Ferguson, J. Moy, "OSPF for IPv6", RFC 2740. 7.2. Informative References [OSPFv3-TE] K. Ishiguro, T. Takada, "Traffic Engineering Extensions to OSPF version 3", draft-ietf-ospf-ospfv3-traffic-01.txt. [OSPF-TE-MESH] J. P. Vasseur, P. Psenak, "OSPF Traffic Engineering Capability TLVs", draft-vasseur-mpls-ospf-te-cap-00.txt. 10.8. Author Information Rahul Aggarwal Juniper Networks 1194 North Mathilda Ave. Sunnyvale, CA 94089 Email: firstname.lastname@example.org Kireeti Kompella Juniper Networks 1194 North Mathilda Ave. Sunnyvale, CA 94089 Email: email@example.com 9. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. 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