draft-ietf-magma-mld-source-02.txt   draft-ietf-magma-mld-source-03.txt 
MAGMA Working Group B. Haberman MAGMA Working Group B. Haberman
draft-ietf-magma-mld-source-02.txt Caspian Networks draft-ietf-magma-mld-source-03.txt Caspian Networks
Expires April 2003 October 2002 Expires April 2003 October 2002
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 33 skipping to change at page 2, line 33
MLD Query messages MUST be sent with a valid link-local address as MLD Query messages MUST be sent with a valid link-local address as
the IPv6 source address. If a router receives a query message with the IPv6 source address. If a router receives a query message with
an IPv6 source address set to the unspecified address (::), it MUST an IPv6 source address set to the unspecified address (::), it MUST
silently discard the message and SHOULD log a warning. silently discard the message and SHOULD log a warning.
MLD Report and Done messages MUST be sent with a valid link-local MLD Report and Done messages MUST be sent with a valid link-local
address as the IPv6 source address. If a valid link-local address is address as the IPv6 source address. If a valid link-local address is
not available, the message MUST be sent with the unspecified address not available, the message MUST be sent with the unspecified address
(::) as the IPv6 source address. (::) as the IPv6 source address.
Source Address Selection Implications
In RFC 2710, MLD Report and Done messages are required to have an
IPv6 source address that is link-local. This memo augments that rule
by allowing these messages to contain the unspecified address (::) as
the source address.
The behavior of RFC 2710 implementations, when receiving a message
with a source address of ::, is dependent upon how the implementation
treats the unspecified address. That is, these messages will be
dropped if the implementation does not consider the unspecified
address to be link-local in scope.
As the unspecified address is only used when there is no link-local
address, RFC 2710 implementations discarding these packets will have
no affect on the packet's sender as the use should only be for
joining the link-local solicited-node multicast group [RFC 2462].
There is an implication to senders with respect to joining other
multicast groups prior to the activation of a link-local address.
The dropping of Reports using the unspecified address as a source
address could cause a lack of multicast traffic that is expected by
the node. This black hole will be termporary until the node can send
a Report with a valid link-local address.
Security Considerations Security Considerations
Security issues related to MLD are discussed in [RFC 2710]. General security issues related to MLD are discussed in [RFC 2710].
The ability to send MLD messages with the unspecified address can
lead to on-link abuse that is harder to trace. However, due to the
expected behavior of RFC 2710 implementations to drop these messages
and the additional rule that Query messages with the unspecified
address be dropped, the impact of such messages will not affect
multicast capabilities on the link.
References References
Normative References Normative References
[RFC 2710] Deering, S., Fenner, W., Haberman, B., "Multicast [RFC 2710] Deering, S., Fenner, W., Haberman, B., "Multicast
Listener Discovery (MLD) for IPv6", RFC 2710, October Listener Discovery (MLD) for IPv6", RFC 2710, October
1999. 1999.
Informative References Informative References
 End of changes. 

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