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Type of Service in the Internet Protocol Suite (RFC1349)

IP.com Disclosure Number: IPCOM000002173D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2019-Feb-11
Document File: 28 page(s) / 40K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

P. Almquist: AUTHOR

Related Documents

10.17487/RFC1349: DOI

Abstract

This memo changes and clarifies some aspects of the semantics of the Type of Service octet in the Internet Protocol (IP) header. [STANDARDS-TRACK]

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 6% of the total text.

Network Working Group P. Almquist Request for Comments: 1349 Consultant Updates: RFCs 1248, 1247, 1195, July 1992 1123, 1122, 1060, 791

Type of Service in the Internet Protocol Suite

Status of This Memo

This document specifies an IAB standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "IAB Official Protocol Standards" for the standardization state and status of this protocol. Distribution of this memo is unlimited.

Summary

This memo changes and clarifies some aspects of the semantics of the Type of Service octet in the Internet Protocol (IP) header. The handling of IP Type of Service by both hosts and routers is specified in some detail.

This memo defines a new TOS value for requesting that the network minimize the monetary cost of transmitting a datagram. A number of additional new TOS values are reserved for future experimentation and standardization. The ability to request that transmission be optimized along multiple axes (previously accomplished by setting multiple TOS bits simultaneously) is removed. Thus, for example, a single datagram can no longer request that the network simultaneously minimize delay and maximize throughput.

In addition, there is a minor conflict between the Host Requirements (RFC-1122 and RFC-1123) and a number of other standards concerning the sizes of the fields in the Type of Service octet. This memo resolves that conflict.

Table of Contents

1. Introduction ............................................... 3

2. Goals and Philosophy ....................................... 3

3. Specification of the Type of Service Octet ................. 4

4. Specification of the TOS Field ............................. 5

Almquist [Page 1]

RFC 1349 Type of Service July 1992

5. Use of the TOS Field in the Internet Protocols ............. 6 5.1 Internet Control Message Protocol (ICMP) ............... 6 5.2 Transport Protocols .................................... 7 5.3 Application Protocols .................................. 7

6. ICMP and the TOS Facility .................................. 8 6.1 Destination Unreachable ................................ 8 6.2 Redirect ............................................... 9

7. Use of the TOS Field in Routing ............................ 9 7.1 Host Routing ........................................... 10 7.2 Forwarding ............................................. 12

8. Other consequences of TOS .................................. 13

APPENDIX A. Updates to Other Specifications ................... 14 A.1 RFC-792 (ICMP) ......................................... 14 A.2 RFC-1060 (Assigned Numbers) ............................ 14 A.3 RFC-1122 and RFC-1123 (Host Requirements) .............. 16 A.4 RFC-1195 (Integrated IS-IS) ............................ 16 A.5 RFC-1247 (OSPF) and RFC-1248 (OSPF MIB) ................ 17

APPENDIX B. Rationale ......................................... 18 B.1 The Minimize Mon...

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