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Using the MARS Model in non-ATM NBMA Networks (RFC2269)

IP.com Disclosure Number: IPCOM000002829D
Original Publication Date: 1998-Jan-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 5 page(s) / 11K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

G. Armitage: AUTHOR

Abstract

Initially developed for IP over ATM, the RFC 2022 (MARS) model is also applicable to other NBMA networks that provide the equivalent of switched, point to multipoint connections. This short document is intended to state the obvious equivalences, and explain the less obvious implications. No changes to the MARS model per se are suggested or required. RFC 2022 is not required over NBMA networks that offer Ethernet-like group addressing functionality.

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Network Working Group G. Armitage

Request for Comments: 2269 Lucent Technologies

Category: Informational January 1998

Using the MARS Model in non-ATM NBMA Networks

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 (1998). All Rights Reserved.

Abstract

Initially developed for IP over ATM, the RFC 2022 (MARS) model is

also applicable to other NBMA networks that provide the equivalent of

switched, point to multipoint connections. This short document is

intended to state the obvious equivalences, and explain the less

obvious implications. No changes to the MARS model per se are

suggested or required. RFC 2022 is not required over NBMA networks

that offer Ethernet-like group addressing functionality.

1. Introduction

Most network layer models, like the one described in STD 5, RFC 1112

[1] for IP multicasting, assume sources may send their packets to an

abstract 'multicast group addresses'. Link layer support for such an

abstraction is assumed to exist, and is provided by technologies such

as Ethernet.

Some NBMA networks (e.g. ATM using UNI3.0 or UNI3.1 signaling [4,5])

do not support a multicast (or group) address abstraction. In these

environments multicasting is typically supported through point to

multipoint calls (or emulated with multiple point to point calls).

The MARS model (RFC 2022) [2] was originally developed by the IP over

ATM working group, and so uses ATM-centric descriptive language. For

completeness this memo explains how RFC 2022 can be applied to other

NBMA technologies.

2. RFC 2022's basic assumptions.

Section 3 of [2] describes the basic assumptions that the MARS model

makes about the services available from the link layer network (using

ATM as the specific case). In summary these are:

The ATM model broadly describes an 'AAL User' as any entity that

establishes and manages VCs and underlying AAL services to

exchange data. An IP over ATM interface is a form of 'AAL User'

The most fundamental limitations of UNI 3.0/3.1's multicast

support are:

Only point to multipoint, unidirectional VCs may be

established.

Only the root (source) node of a given VC may add or remove

leaf nodes.

Leaf nodes are identified by their unicast ATM addresses.

Given this point to multipoint call service, the MAR...