draft-ietf-magma-mld-source-06.txt   draft-ietf-magma-mld-source-07.txt 
MAGMA Working Group B. Haberman MAGMA Working Group B. Haberman
draft-ietf-magma-mld-source-06.txt Caspian Networks draft-ietf-magma-mld-source-07.txt Caspian Networks
Expires December 2003 June 2003 Expires December 2003 June 2003
Source Address Selection for Multicast Source Address Selection for Multicast
Listener Discovery Protocol (RFC 2710) Listener Discovery Protocol (RFC 2710)
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
skipping to change at page 2, line 26 skipping to change at page 2, line 26
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC 2119]. document are to be interpreted as described in [RFC 2119].
Justification Justification
In [RFC 2710], Section 3 requires that all MLD messages be sent with 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 a valid link-local IPv6 source address. However, a node in the
process of performing duplicate address detection for its link-local process of performing duplicate address detection for its link-local
address will not have one available to use as a source address. For address will not have one available to use as a source address. For
this reason, this document provides an alternative IPv6 source this reason, this document allows the unspecified address to be used
address for MLD messages being used during duplicate address as a source address for MLD messages being used during duplicate
detection.
In addition, Sections 5 and 6 of [RFC 2710] mandates that a node
receiving an MLD Report message verify that the IPv6 source address
is a link-local address. This document relaxes this rule in order to
support the alternative IPv6 source address in use during duplicate
address detection. address detection.
The discrepencies in the rules defined in [RFC 2710] and [RFC 2462] The discrepencies in the rules defined in [RFC 2710] and [RFC 2462]
has led to implementation issues. Several IPv6 implementations skip has led to implementation issues. Several IPv6 implementations skip
sending MLD Report messages during duplicate address detection sending MLD Report messages during duplicate address detection
because they have no valid link-local address. This leads to because they have no valid link-local address. This leads to
operational problems when a node is attached to switches that perform operational problems when a node is attached to switches that perform
MLD snooping. In this scenario, duplicate address detection will MLD snooping. In this scenario, duplicate address detection will
complete successfully and collisions can occur once the address is complete successfully and collisions can occur once the address is
put into use because switches may not have forwarded the DAD messages put into use because switches may not have forwarded the DAD messages
 End of changes. 

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