Internet Draft Internet Draft W. Wimer Expires: August 31, 1999 FORE Systems, Inc. <draft-wimer-ospf-traffic-00.txt> February 1999 Additional OSPF Extensions for Traffic Engineering and QoS Routing 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." To view the list Internet-Draft Shadow Directories, see http://www.ietf.org/shadow.html. Abstract OSPF is a link-state IP interior routing protocol specified in [1]. Several different extensions to OSPF have been proposed [2,3,5] to support Traffic Engineering [4] and Quality of Service routing [5]. This document acknowledges all of this earlier work and proposes that a single style of protocol encoding be used for all of the parameters involved. This document employs the OSPF Opaque LSA Option [6] and the TVLV mechanism proposed in [3] to encode additional parameters describing information about the state of an OSPF network. This additional information is useful for Traffic Engineering and QoS-based routing. Wimer Expires August 31, 1999 [Page 1] Internet Draft QoS Extensions for OSPF February 1999 1. Introduction A set of Traffic Engineering parameters are defined in [3] along with an extensible mechanism for encoding these within an OSPF Type 10 Opaque LSA. This document proposes additional parameters that are useful for Traffic Engineering and QoS-based routing. This document only defines the layout of additional traffic engineering information in the opaque LSA using the TVLV mechanism. Unless stated otherwise, procedures for obtaining this information, and the use of this information (either within or outside of OSPF) is outside the scope of this document. 2. Sub-TVLVs of the Neighbor TVLV. This section proposes the following additional sub-TVLVs of the Neighbor TVLV: Sub-TVLV type Length (Octets) Value (Octets) Name 7 1 4 Link Propagation Delay 8 variable 4*N Link Drop Ratios 2.1. Sub-TVLV 7: Link Propagation Delay This sub-TVLV specifies the propagation delay incurred on this link in this direction (from the router originating the LSA to its neighbors). This quantity is meant to identify high latency links, e.g., satellite links, which may be unsuitable for real-time requests. Propagation delay is encoded in 32 bits in IEEE 754 floating point format. The units are microseconds. 2.2. Sub-TVLV 8: Link Drop Ratios This sub-TVLV is used to specify packet drop ratios corresponding to Differentiated Services codepoints [8,9]. The "Length" field of this sub-TVLV must contain a multiple of 4. The "Value" portion of this sub-TVLV consists of a contiguous set of Wimer Expires August 31, 1999 [Page 2] Internet Draft QoS Extensions for OSPF February 1999 one or more 32-bit Drop Ratio Descriptors. The number of Descriptors present is equal to the "Length" of the sub-TVLV divided by 4. Each Drop Ratio Descriptor has the following form: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | DSCP |Rsv| Drop Ratio | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Reserved This 8-bit field is reserved for future use. It must be zero when transmitted and ignored upon receipt. DSCP This 6-bit field represents a Differentiated Services codepoint. Rsv This 2-bit field is reserved for future use. It must be zero when transmitted and ignored upon receipt. Drop Ratio This 16-bit field is an unsigned 16-bit integer representing the ratio of the number of lost outbound packets (generally lost due to queueing drop) to the total number of outbound packets, corresponding to the Differentiated Services codepoint specified in the DSCP field. For example, a value of 0 implies 0/65536 or no drops. A value of 1 implies 1/65536 or a drop ratio of approximately 0.0015 percent. A value of 32768 implies 32768/65536 or a drop ratio of 50 percent. A value of 65535 implies 65535/65536 or a drop ratio of approximately 99.998 percent (essentially 100 percent). 3. Security Considerations This document raises no new security issues for OSPF. Wimer Expires August 31, 1999 [Page 3] Internet Draft QoS Extensions for OSPF February 1999 4. Acknowledgments The author would like to gratefully acknowledge the prior work on IS-IS and OSPF Traffic Engineering and QoS extensions cited in [2,3,5,7]. 5. References [1] RFC 2328 OSPF Version 2. J. Moy. April 1998. (Format: TXT=447367 bytes) (Obsoletes RFC2178) (Also STD0054) (Status: STANDARD) [2] drft-ietf-ospf-omp-01.txt, "OSPF Optimized Multipath (OSPF-OMP)", C. Villamizar, work in progress. [3] draft-yeung-ospf-traffic-00.txt, "OSPF Extensions for Traffic Engineering", D. Yeung, work in progress. [4] draft-ietf-mpls-traffic-eng-00.txt, "Requirements for Traffic Engineering Over MPLS", D. Awduche, J. Malcolm, J. Agogbua, M. O'Dell, J. McManus, work in progress. [5] draft-guerin-ospf-routing-ospf-04.txt, "QoS Routing Mechanisms and OSPF Extensions", G. Apostolopoulos, R. Guerin, et al., work in progress. [6] RFC 2370 The OSPF Opaque LSA Option. R. Coltun. July 1998. (Format: TXT=33789 bytes) (Also RFC2328) (Status: PROPOSED STANDARD) [7] draft-ietf-isis-traffic-00.txt, "ISIS Extensions for Traffic Engineering", H. Smit, T. Li, work in progress. [8] RFC 2474 Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers. K. Nichols, S. Blake, F. Baker, D. Black. December 1998. (Obsoletes RFC1455, RFC1349) (Status: PROPOSED STANDARD) [9] RFC 2475 An Architecture for Differentiated Services. S. Blake, D. Black, M. Carlson, E. Davies, Z. Wang, W. Weiss. December 1998. (Status: PROPOSED STANDARD) Wimer Expires August 31, 1999 [Page 4] Internet Draft QoS Extensions for OSPF February 1999 6. Author's Address Walt Wimer FORE Systems, Inc. 1000 FORE Drive Warrendale, PA 15086-7502 Phone: 724-742-7324 EMail: wwimer@fore.com Wimer Expires August 31, 1999 [Page 5]