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Considerations on the use of a Service Identifier in Packet Headers (RFC3639)

IP.com Disclosure Number: IPCOM000019911D
Original Publication Date: 2003-Oct-01
Included in the Prior Art Database: 2003-Oct-10
Document File: 9 page(s) / 15K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

M. St. Johns: AUTHOR [+5]

Abstract

This memo describes some considerations relating to the use of IP protocol number fields and payload protocol (e.g., TCP) port fields to identify particular services that may be associated with that port number or protocol number.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 22% of the total text.

Network Working Group M. St. Johns, Ed.

Request for Comments: 3639 G. Huston, Ed.

Category: Informational IAB

October 2003

Considerations on the use of a

Service Identifier in Packet Headers

Status of this Memo

This memo provides information for the Internet community. It does

not specify an Internet standard of any kind. Distribution of this

memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

This memo describes some considerations relating to the use of IP

protocol number fields and payload protocol (e.g., TCP) port fields

to identify particular services that may be associated with that port

number or protocol number.

1. Introduction

This memo describes some considerations relating to the use of IP

protocol number fields and payload protocol (e.g., TCP) port or

service fields to identify particular services that may be associated

with that port number or protocol number. It is a general statement

regarding appropriate processing and use of service identifiers by

intermediate systems.

This memo points out that various measures by intermediate systems

that are intended to filter or prevent the transmission of traffic

based on the service identification within the traffic flow will have

a limited effect. This will also have a major side-effect of

forcing the affected services to be redesigned using various forms of

encapsulation or dynamic port negotiation in order to remove the

fixed service identification from the IP packet headers. The IAB

does not believe this serves the general interests of the Internet

community related to the design of simple and reliable Internet

applications. This memo suggests some thought be given to control

mechanisms that do not rely on intermediary systems taking actions

based on an assumed relationship between the service identifier in

the packet and the actual service of which the packet is a part.

St. Johns & Huston Informational [Page 1]

RFC 3639 Service Identifier in Packet Headers October 2003

2. Service Identifiers

Although not necessarily by design, certain conventions have evolved

with respect to the IP protocol suite relative to the identification

of services within an IP traffic flow:

o Within the IP protocol suite, end point identifiers (e.g.,

TCP/UDP/SCTP port numbers, IP protocol numbers) are designed to

identify services to end points. In particular, TCP, UDP or SCTP

(Stream Control Transmission Protocol) port numbers are intended

to identify the source service location and the destination

service entity to the destination end point.

o The IP [2] datagram header contains the source and destination

address of the datagram as well as an indication of the upper-

level protocol (ULP) carried within the datagram. If the ULP is

either TCP [3], UDP [1], or SCTP [8] the payload will contain both

source and destination port numbers which allows differentiation

between services (e.g., TELNET, HTTP) and between multiple

instances of the same service bet...