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Source Address Selection for the Multicast Listener Discovery (MLD) Protocol (RFC3590)

IP.com Disclosure Number: IPCOM000019263D
Original Publication Date: 2003-Sep-01
Included in the Prior Art Database: 2003-Sep-09
Document File: 7 page(s) / 12K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

B. Haberman: AUTHOR

Abstract

It has come to light that there is an issue with the selection of a suitable IPv6 source address for Multicast Listener Discovery (MLD) messages when a node is performing stateless address autoconfiguration. This document is intended to clarify the rules on selecting an IPv6 address to use for MLD messages.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 29% of the total text.

Network Working Group B. Haberman

Request for Comments: 3590 Caspian Networks

Updates: 2710 September 2003

Category: Standards Track

Source Address Selection for the

Multicast Listener Discovery (MLD) Protocol

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 (2003). All Rights Reserved.

Abstract

It has come to light that there is an issue with the selection of a

suitable IPv6 source address for Multicast Listener Discovery (MLD)

messages when a node is performing stateless address

autoconfiguration. This document is intended to clarify the rules on

selecting an IPv6 address to use for MLD messages.

1. Introduction

The original specification of the Multicast Listener Discovery

Protocol (MLD) for IPv6 [RFC 2710] mandates the use of a link-local

IPv6 source address for the transmission of MLD messages. In

addition, MLD also requires nodes to send MLD Report messages when

joining any IPv6 multicast group (except the All-Nodes address and

addresses of scope less than 2).

These MLD requirements conflict with the use of IPv6 multicast within

the Neighbor Discovery Protocol [RFC 2461]. For stateless

autoconfiguration, as defined in [RFC 2462], a node is required to

join several IPv6 multicast groups in order to perform Duplicate

Address Detection prior to its use. Since the only address the node

has is tentative, and cannot be used for communication, it does not

have a suitable address to utilize as a source address.

Haberman Standards Track [Page 1]

RFC 3590 Source Address Selection for MLD Protocol September 2003

This document will clarify the IPv6 source address selection rules

for use with MLD when no link-local addresses are available.

2. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",

"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this

document are to be interpreted as described in [RFC 2119].

3. Justification

In [RFC 2710], Section 3 requires that all MLD messages be sent with

a valid link-local IPv6 source address. However, a node in the

process of performing duplicate address detection for its link-local

(LL) address will not have one available to use as a source address.

For this reason, this document allows the unspecified address to be

used as a source address for MLD messages being used during duplicate

address detection.

The discrepancies in the rules defined in [RFC 2710] and [RFC 2462]

has led to implementation issues. Several IPv6 implementations skip

sending MLD Report messages during duplicate address detection

because they have no valid link-local address. This leads to

operational problems when a node is attached to switches that...