IPv6 over Non-Broadcast Multiple Access (NBMA) networks (RFC2491)

Network Working Group G. Armitage Request for Comments: 2491 Lucent Technologies Category: Standards Track P. Schulter Bright Tiger Technologies M. Jork Digital Equipment GmbH G. Harter Compaq January 1999

IPv6 over Non-Broadcast Multiple Access (NBMA) networks

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 document describes a general architecture for IPv6 over NBMA networks. It forms the basis for subsidiary companion documents that describe details for various specific NBMA technologies (such as ATM or Frame Relay). The IPv6 over NBMA architecture allows conventional host-side operation of the IPv6 Neighbor Discovery protocol, while also supporting the establishment of ’shortcut’ NBMA forwarding paths when dynamically signaled NBMA links are available. Operations over administratively configured Point to Point NBMA links are also described.

Dynamic NBMA shortcuts are achieved through the use of IPv6 Neighbor Discovery protocol operation within Logical Links, and inter-router NHRP for the discovery of off-Link NBMA destinations. Both flow- triggered and explicitly source-triggered shortcuts are supported.

1. Introduction.

Non Broadcast Multiple Access (NBMA) networks may be utilized in a variety of ways. At one extreme, they can be used to simply provide administratively configurable point to point service, sufficient to interconnect IPv6 routers (and even IPv6 hosts, in certain

Armitage, et. al. Standards Track [Page 1]

RFC 2491 IPv6 over NBMA networks January 1999

situations). At the other extreme, NBMA networks that support dynamic establishment and teardown of Virtual Circuits (or functional equivalents) may be used to emulate the service provided to the IPv6 layer by conventional broadcast media such as Ethernet. Typically this emulation requires complex convergence protocols, particularly to support IPv6 multicast.

This document describes a general architecture for IPv6 over NBMA networks. It forms the basis for companion documents that provide details specific to various NBMA technologies (for example, ATM [17] or Frame Relay). The IPv6 over NBMA architecture allows conventional host-side operation of the IPv6 Neighbor Discovery protocol, while also supporting the establishment of ’shortcut’ NBMA forwarding paths (when dynamically signaled NBMA links are available).

The majority of this document focuses on the use of dynamically managed point to point and point to multipoint calls between interfaces on an NBMA network. These will be generically referred to as "SVCs" in the rest of the document. The use of administratively configured poin...