Network Working Group R. Aggarwal Internet Draft Juniper Networks Category: Standards Track Expiration Date: May 2009 K. Kompella Juniper Networks November 18, 2008 Advertising a Router's Local Addresses in OSPF TE Extensions draft-ietf-ospf-te-node-addr-05.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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. Abstract OSPF Traffic Engineering (TE) extensions are used to advertise TE Link State Advertisements (LSAs) containing information about TE- enabled links. 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. In order to allow other routers in a network to compute Multiprotocol Label Switching (MPLS) traffic engineered Label Switched Paths (TE LSPs) to a given router's local addresses, those addresses must also Raggarwa & Kompella [Page 1] Internet Draft draft-ietf-ospf-te-node-addr-05.txt November 2008 be advertised by OSPF TE. This document describes procedures that enhance OSPF TE to advertise a router's local addresses. Table of Contents 1 Specification of requirements ......................... 2 2 Motivation ............................................ 3 3 Rejected Potential Solution ........................... 3 4 Solution .............................................. 4 4.1 Node Attribute TLV .................................... 4 4.2 Operation ............................................. 5 5 Security Considerations ............................... 6 6 IANA Considerations ................................... 6 7 Acknowledgments ....................................... 6 8 References ............................................ 6 8.1 Normative References .................................. 6 8.2 Informative References ................................ 7 9 Author's Address ...................................... 7 10 Intellectual Property Statement ....................... 7 11 Copyright Notice ...................................... 8 1. Specification of requirements 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 [RFC2119]. Raggarwa & Kompella [Page 2] Internet Draft draft-ietf-ospf-te-node-addr-05.txt November 2008 2. Motivation In some cases it is desirable to set up constrained shortest path first (CSPF) computed Multiprotocol Label Switching (MPLS) Traffic Engineered Label Switched Paths (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 [OSPF], 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. 3. Rejected 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. Raggarwa & Kompella [Page 3] Internet Draft draft-ietf-ospf-te-node-addr-05.txt November 2008 4. Solution The solution is to advertise the local addresses of a router in a new OSPF TE LSA node attribute TLV. It is anticipated that the node attribute TLV will also prove more generally useful. 4.1. 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Prefix Len 1 | IPv4 Prefix 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Prefix 1 cont. | : +-+-+-+-+-+-+-+-+ ~ : . : ~ . +-+-+-+-+-+-+-+-+ : . | Prefix Len n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Prefix n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Each local IPv4 address is encoded as a tuple. Prefix Length is encoded in 1 byte. It is the number of bits in the Address and can be at most 32. Prefix is an IPv4 address prefix and is encoded in 4 bytes with zero bits as necessary. The Node IPv4 Local Address sub-TLV length is in octets. It is the sum of all n IPv4 Address encodings in the sub-TLV 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 Raggarwa & Kompella [Page 4] Internet Draft draft-ietf-ospf-te-node-addr-05.txt November 2008 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Prefix Len 1 | Prefix 1 Opt. | IPv6 Prefix 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 Prefix 1 cont. : : . ~ ~ . : . : +-+-+-+-+-++-+-+-+-+-++-+-+-+-+-+ : | Prefix Len n | Prefix n Opt. | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 Prefix n : | : +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-- Each local IPv6 address is encoded using the procedures in [OSPv3]. Each IPv6 address MUST be represented by a combination of three fields: PrefixLength, PrefixOptions, and Address Prefix. PrefixLength is the length in bits of the prefix and is an 8 bit field. PrefixOptions is an 8-bit field describing various capabilities associated with the prefix [OSPFv3]. Address Prefix is an encoding of the prefix itself as an even multiple of 32-bit words, padding with zero bits as necessary. This encoding consumes (PrefixLength + 31) / 32) 32-bit words. The Node IPv6 Local Address sub-TLV length is in octets. It is the sum of all n IPv6 Address encodings in the sub-TLV where n is the number of local addresses included in the sub-TLV. 4.2. 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. The node attribute TLV must appear in exactly one TE LSA originated by a router. Further only one node attribute TLV must be advertised in such a LSA. A node attribute TLV must carry at most one Node IPv4 Local Address sub-TLV and at most one Node IPv6 Local Address sub- TLV. Raggarwa & Kompella [Page 5] Internet Draft draft-ietf-ospf-te-node-addr-05.txt November 2008 5. Security Considerations This document does not introduce any further security issues other than those discussed in [OSPF-TE, OSPFv3-TE]. 6. IANA Considerations The Node Attribute TLV type has to be IANA assigned from the range 3 - 32767 as specified in [OSPF-TE], from the top level types in TE LSAs registry maintained by IANA at [IANA-OSPF-TE]. IANA is requested to maintain the registry for the sub-TLVs of the node attribute TLV and reserve value 1 for Node IPv4 Local Address sub-TLV and value 2 for Node IPv6 Local Address sub-TLV. 7. 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, Dimitri Papadimitriou and Adrian Farrel for their comments. 8. References 8.1. Normative References [OSPF] Moy, J., "OSPF Version 2", RFC 2328, April 1998. [RFC2119] 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. Raggarwa & Kompella [Page 6] Internet Draft draft-ietf-ospf-te-node-addr-05.txt November 2008 8.2. Informative References [OSPFv3-TE] K. Ishiguro, T. Takada, "Traffic Engineering Extensions to OSPF version 3", draft-ietf-ospf-ospfv3-traffic-09.txt. [IANA-OSPF-TE] http://www.iana.org/assignments/ospf-traffic-eng-tlvs 9. Author's Address Rahul Aggarwal Juniper Networks 1194 North Mathilda Ave. Sunnyvale, CA 94089 Phone: +1-408-936-2720 Email: rahul@juniper.net Kireeti Kompella Juniper Networks 1194 North Mathilda Ave. Sunnyvale, CA 94089 Email: kireeti@juniper.net 10. Intellectual Property Statement 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. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any Raggarwa & Kompella [Page 7] Internet Draft draft-ietf-ospf-te-node-addr-05.txt November 2008 copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf- ipr@ietf.org. 11. Copyright Notice Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Raggarwa & Kompella [Page 8]