Network Working Group Muneyoshi Suzuki INTERNET DRAFT NTT Expires November 21 , 1996 May 21, 1996 ST FlowSpec for the Controlled-Load Service Status of this Memo This document is an Internet-Draft. 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 learn the current status of any Internet-Draft, please check the "1id-abstracts.txt" listing contained in the Internet- Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Abstract This memo specifies the ST FlowSpec format for the Controlled-Load service. The ST FlowSpec described in this memo applies to both RFC1190 ST2 and RFC1819 ST2+. 1. Introduction This memo specifies the ST FlowSpec format for the Controlled-Load service defined in [1]. The ST FlowSpec described in this memo applies to both the RFC1190 ST2 [2] and the RFC1819 ST2+ [3]. This FlowSpec does not support parameter negotiations except for maximum packet size. This is because, in the ST2 and ST2+ environment, negotiated FlowSpec parameters are not always unique to each target. It is difficult for current datalink technologies to support heterogeneous traffic parameters to multiple receivers. Suzuki Expires November, 1996 [Page 1] INTERNET DRAFT draft-suzuki-stfs-ctrl-load-svc-00.txt May, 1996 2. FlowSpec Format The ST FlowSpec and RFlowSpec for the Controlled-Load Service have 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PCode | PBytes = 28 | ST FS Ver = 8 | 0(unused) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ver=0 | 0(unused) | Overall Length = 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Service Num = 5|Data Length = 4| Param ID = 1 | 0(unused) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Token Bucket Rate [r] (32-bit IEEE floating point number) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Token Bucket Size [b] (32-bit IEEE floating point number) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Minimum Policed Unit [m] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Maximum Packet Size [M] | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The PCode field identifies common SCMP elements. The PCode value for the ST2 FlowSpec is two (2), for the ST2 RFlowSpec it is twelve (12), and for the ST2+ FlowSpec it is one (1). The PBytes field for the Controlled-Load Service is twenty-eight (28) bytes. The ST FS Ver (ST FlowSpec Version) field identifies the ST FlowSpec version. The ST FlowSpec version number for the Integrated Services is eight (8). The Ver (Controlled-Load Service Version) field identifies the Controlled-Load Service version number. The current version is zero (0). The Overall Length field is always set to five (5) words. The Service Num (Service Number) for the Controlled-Load Service is five (5). The Data Length (Per-Service Data Length) field is always set to four (4) words. The Param ID (Parameter ID) field is always set to one (1). Suzuki Expires November, 1996 [Page 2] INTERNET DRAFT draft-suzuki-stfs-ctrl-load-svc-00.txt May, 1996 Intention of this field is compatibility with the Integrated Services FlowSpec format for the RSVP and does not have another meaning. Definitions of the Token Bucket Rate [r], the Token Bucket Size [b], the Minimum Policed Unit [m] and the Maximum Packet Size [M] fields are given in [1]. See section 5 of [1] for details. The ST2 or ST2+ agent, that creates the FlowSpec or the RFlowSpec element in the SCMP message, must assign valid values to all fields. The other agents must not modify any values except for the [M] field in the CONNECT message. The [M] field in the CONNECT message is assigned by the origin or the intermediate agent acting as origin, and updated by each agent based on the MTU value of the datalink layer. The negotiated value of [M] is set back to the origin or the intermediate agent acting as origin using the [M] field in the ACCEPT message that corresponds to the CONNECT message. In the original definition of the Controlled-Load Service, the value of the [m] field must be less than or equal to the value of the [M] field. However, in the ST FlowSpec for the Controlled-Load Service, if the value of the [M] field is less than that of the [m] field, the value of the [m] field is regarded as the same value as the [M] field, and must not generate an error. This is because there is a possibility that the value of the [M] field in the CONNECT message may be decreased by negotiation. In the ST2+ SCMP messages, the value of the [M] field must be equal to or less than 65535. In the ST2+ CONNECT message, the ACCEPT message that responds to CONNECT, or the NOTIFY message that contains the FlowSpec field, the value of the [M] field must be equal to the MaxMsgSize field in the message. If these values are not the same, FlowSpec is regarded as an error. If the ST2 or ST2+ agent receives the CONNECT message that contains unacceptable FlowSpec, the agent must generate the REFUSE message. The ST FlowSpec for the Controlled-Load Service does not have the Precedence (see section 4.2.2.3 of [2] or section 9.2.2 of [3]) field. All of the ST2 and ST2+ functions that depend on the Precedence (ex. stream preemption of the ST2+) are not supported. Suzuki Expires November, 1996 [Page 3] INTERNET DRAFT draft-suzuki-stfs-ctrl-load-svc-00.txt May, 1996 3. Security Considerations Security considerations are not discussed in this memo. References [1] J. Wroclawski, "Specification of the Controlled-Load Network Element Service", Internet Draft, November 1995, [2] C. Topolcic, Ed., "Experimental Internet Stream Protocol, Version 2 (ST-II)", RFC 1190, October 1990. [3] L. Delgrossi, L. Berger, Ed., "Internet Stream Protocol Version 2 (ST2) Protocol Specification - Version ST2+", RFC 1819, August 1995. Acknowledgments I would like to thank for valuable comments from Eric Crawley of BayNetworks and Steve Jackowski of NetManage. Author's Address Muneyoshi Suzuki NTT Telecommunication Networks Laboratories 3-9-11, Midori-cho Musashino-shi, Tokyo 180 Japan Phone: +81-422-59-2119 Fax: +81-422-59-3203 EMail: suzuki@nal.ntt.jp Suzuki Expires November, 1996 [Page 4]