Subject: Auxiliary data field

From: Thomas Eriksson <[email-masked]>
Date: Tue, 21 Aug 2001 16:32:17 +0200

Hi,

I have been pondering over the auxiliary data field, found in the group
record of the IGMPv3 membership report message. A pointer to previous
discussions on the issue why the working group decided to add the field
would be appreciated. A summary of them would be even more appreciated.

Thomas

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From: Bill Fenner <[email-masked]>
Date: Tue, 28 Aug 2001 20:28:51 -0700

It's an extension mechanism.  In previous IGMP versions, each message
contained a fixed-length report about a single group, so any extensions
could unambiguously be appended to the packet.  Since IGMPv3 has
variable-length reports, potentially with multiple groups, in order to
keep the same extension ability we added the auxilliary data field.

I don't know if anyone has any concrete ideas for what to use the
field for; one thing that's been suggested several times is to
provide authentication information.

  Bill