Internet Draft Network Working Group Norihito Fujita Internet Draft Atsushi Iwata <draft-fujita-ospf-te-summary-00.txt> NEC Corporation Expires in six months March 2000 Traffic Engineering Extensions to OSPF Summary LSA <draft-fujita-ospf-te-summary-00.txt> Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 Various Traffic Engineering extensions for OSPF have been proposed in [KATZ, OSPFEXT] and others. However, these are basically applicable only to intra-area Traffic Engineering since they do not support inter-area advertisements of the resource information. This draft proposes a new scheme for advertising the summarized resource information for Traffic Engineering outside the area. It also specifies a new LSA to achieve this advertisement. 1. Introduction Advertising resource information in addition to topology information using link state protocols is useful for achieving Traffic Engineering in a network. Various Traffic Engineering extensions for OSPF have been proposed in [KATZ, OSPFEXT] and others. For example, [KATZ] proposes to extend OSPF using the Opaque LSA so as to Fujita & Iwata draft-fujita-ospf-te-summary-00.txt [Page 1] Internet Draft March 2000 advertise the parameters concerning Traffic Engineering. In these proposals, however, the flooding scope of such an advertisement is area-local, so the resource information is never advertised across area border routers. In a hierarchical OSPF environment, therefore, Traffic Engineering with Autonomous System (AS) scope is currently impossible. This draft proposes to advertise the summarized resource information outside the area, which would allow Traffic Engineering with AS scope. We specify the summarization schemes and the new LSA for the advertisement. 2. Traffic Engineering Extensions to OSPF Summary LSA 2.1. Overview We assume that resource information for Traffic Engineering is advertised with an area-local scope by the Traffic Engineering LSA (TE-LSA) proposed in [KATZ]. Using this information, the summarized resource information for each destination network is computed and advertised in addition to the OSPF Summary-LSA. One new LSA, the TE-Summary LSA, is defined for the advertisement, which makes use of the Opaque LSA encoding [OPAQUE]. We address the summarization of the following resource information in this draft. The support of other parameters is for further study. Traffic Engineering Metric The metric to the destination network used for Traffic Engineering purposes. Maximum Reservable Bandwidth The maximum bandwidth that may be reserved on the path to the corresponding destination network. This value may be greater than the maximum bandwidth along the path, in which case the path may be oversubscribed. Unreserved Bandwidth The amount of bandwidth that is not yet reserved on the path to the corresponding destination network. The value is less than or equal to the maximum reservable bandwidth. Available Bandwidth The amount of bandwidth that is not currently occupied by actual traffic flows on the path to the corresponding destination network. This value can be determined by monitoring the actual amount of data traffic. Fujita & Iwata draft-fujita-ospf-te-summary-00.txt [Page 2] Internet Draft March 2000 This draft does not address resource class (or color). The resource information included in the proposed TE-Summary LSA is aggregated in a single class, whose value can be shared by multiple classes. 2.2. Summarization of Resource Information The resource information for each destination network is summarized at the area border routers and then is advertised throughout the neighboring areas. Summarization schemes are different depending on whether the destination network is located within the same area as the area border router or not. In the former case, the summarization of resource information is performed based only on resource information from the TE-LSAs advertised in the area. If the destination network is not located within the same area as the area border router, summarization requires resource information from outside the area. The summarized resource information that is advertised through the TE-Summary LSAs for the corresponding destination network is taken into account together with the TE-LSAs. This means that the area border router calculates the resource values along the end-to-end available paths that go across area border routers toward the destination network in the new TE-Summary LSA. The methods of computing resource values included in the TE-Summary LSAs may have to be standardized, but is left for further study. 2.3. Advertisement of TE-Summary LSA The TE-Summary LSA is advertised together whenever a standard Summary-LSA is advertised. Furthermore, whenever an area border router calculates the summarized bandwidth or metric based on the received resource information, it compares the calculated value to the value that it advertised previously. If the change exceeds the pre-determined threshold value or ratio, a TE-Summary LSA with the updated information is re- advertised. Fujita & Iwata draft-fujita-ospf-te-summary-00.txt [Page 3] Internet Draft March 2000 2.4. TE-Summary LSA 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LS age | Options | 10 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Opaque Type | Opaque ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Advertising Router | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LS sequence number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LS checksum | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination IP Network Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Mask | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 0 | TE Metric | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Maximum Reservable Bandwidth | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Available Bandwidth | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Opaque Type The type value is to be discussed. Opaque ID The arbitrary value used to maintain multiple TE-Summary LSAs is included. Destination IP Network Number The same value as the Link State ID of the corresponding Summary- LSA is included. Network Mask This indicates the destination network's IP address mask. The same value as the Network Mask of the corresponding Summary-LSA is included. TE Metric The TE metric is used for Traffic Engineering purposes. This metric may be different than the standard Summary-LSA's TOS 0 metric. Fujita & Iwata draft-fujita-ospf-te-summary-00.txt [Page 4] Internet Draft March 2000 Maximum Reservable Bandwidth The summarized maximum reservable bandwidth for the corresponding destination is included. The bandwidth is encoded in IEEE single- precision floating-point format. Unreserved Bandwidth The summarized unreserved bandwidth for the corresponding destination is included. The bandwidth is encoded in IEEE single- precision floating-point format. Available Bandwidth The summarized available bandwidth for the corresponding destination is included. The bandwidth is encoded in IEEE single- precision floating-point format. 4. Security Considerations Security considerations are not addressed in this version of the draft. 5. References [OSPF] J. Moy, "OSPF Version 2", RFC2328, April 1998. [OSPFEXT] G. Apostolopoulos, D. Williams, S. Kamat, R. Guerin, A. Orda T. Przygienda, "QoS Routing Mechanisms and OSPF Extensions", RFC2676, August 1999. [KATZ] Dave Katz, Derek Yeung, "Traffic Engineering Extensions to OSPF", <draft-katz-yeung-ospf-traffic-01.txt>, October 1999. [OPAQUE] R. Coltun, "The OSPF Opaque LSA Option", RFC2370, July 1998. 6. Authors' Addresses Norihito Fujita NEC Corporation C&C Media Research Laboratories 1-1, Miyazaki, 4-Chome, Miyamae-ku, Kawasaki, Kanagawa, 216-8555, JAPAN Phone: +81 (44) 856-2123 Fax: +81 (44) 856-2230 Email: n-fujita@ccm.cl.nec.co.jp Atsushi Iwata NEC Corporation C&C Media Research Laboratories Fujita & Iwata draft-fujita-ospf-te-summary-00.txt [Page 5] Internet Draft March 2000 1-1, Miyazaki, 4-Chome, Miyamae-ku, Kawasaki, Kanagawa, 216-8555, JAPAN Phone: +81 (44) 856-2123 Fax: +81 (44) 856-2230 Email: iwata@ccm.cl.nec.co.jp Fujita & Iwata draft-fujita-ospf-te-summary-00.txt [Page 6]