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Multiprotocol Encapsulation over ATM Adaptation Layer 5 (RFC2684)

IP.com Disclosure Number: IPCOM000003276D
Original Publication Date: 1999-Sep-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 18 page(s) / 48K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

D. Grossman: AUTHOR [+2]

Abstract

This memo replaces RFC 1483. It describes two encapsulations methods for carrying network interconnect traffic over AAL type 5 over ATM. The first method allows multiplexing of multiple protocols over a single ATM virtual connection whereas the second method assumes that each protocol is carried over a separate ATM virtual connection.

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 6% of the total text.

Network Working Group D. Grossman

Request for Comments: 2684 Motorola, Inc.

Obsoletes: 1483 J. Heinanen

Category: Standards Track Telia

September 1999

Multiprotocol Encapsulation over ATM Adaptation Layer 5

Status of this Memo

This document specifies an Internet standards track protocol for the

Internet community, and requests discussion and suggestions for

improvements. Please refer to the current edition of the "Internet

Official Protocol Standards" (STD 1) for the standardization state

and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (1999). All Rights Reserved.

Abstract

This memo replaces RFC 1483. It describes two encapsulations methods

for carrying network interconnect traffic over AAL type 5 over ATM.

The first method allows multiplexing of multiple protocols over a

single ATM virtual connection whereas the second method assumes that

each protocol is carried over a separate ATM virtual connection.

Applicability

This specification is intended to be used in implementations which

use ATM networks to carry multiprotocol traffic among hosts, routers

and bridges which are ATM end systems.

1. Introduction

Asynchronous Transfer Mode (ATM) wide area, campus and local area

networks are used to transport IP datagrams and other connectionless

traffic between hosts, routers, bridges and other networking devices.

This memo describes two methods for carrying connectionless routed

and bridged Protocol Data Units (PDUs) over an ATM network. The "LLC

Encapsulation" method allows multiplexing of multiple protocols over

a single ATM virtual connection (VC). The protocol type of each PDU

is identified by a prefixed IEEE 802.2 Logical Link Control (LLC)

header. In the "VC Multiplexing" method, each ATM VC carries PDUs of

exactly one protocol type. When multiple protocols need to be

transported, there is a separate VC for each.

The unit of transport in ATM is a 53 octet fixed length PDU called a

cell. A cell consists of a 5 octet header and a 48 byte payload.

Variable length PDUs, including those addressed in this memo, must be

segmented by the transmitter to fit into the 48 octet ATM cell

payload, and reassembled by the receiver. This memo specifies the

use of the ATM Adaptation Layer type 5 (AAL5), as defined in ITU-T

Recommendation I.363.5 [2] for this purpose. Variable length PDUs are

carried in the Payload field of the AAL5 Common Part Convergence

Sublayer (CPCS) PDU.

This memo only describes how routed and bridged PDUs are carried

directly over the AAL5 CPCS, i.e., when the Service Specific

Convergence Sublayer (SSCS) of AAL5 is absent. If Frame Relay

Service Specific Convergence Sublayer (FR-SS...