Re: [DNA] MLD JOIN Questions?

[Greg Daley <greg.daley@eng.monash.edu.au>]

Hi Sathya.

I've written some answers to your questions, in the rough
form of a text proposal:


Sathya Narayanan wrote:
> Before I forget, I just wanted to capture the questions and post them. The questions are:
> 
> 1) When should the host do MLD join solicited node multicast group(s)?
>   - After marking the IPv6 addresses as optimistic, or
>   - Just before sending RS message or
>   - someother time

The host SHOULD send the MLD group join report for the solicited node's
multicast group when it becomes optimistic.  Note that this may precede
transmission of the DAD NS probe by some time, although the optimistic
node's ability to receive DAD NS's is limited until it does so.

In any case, the MLD report message MUST be sent before transmission of
either an RS, otherwise responding routers may not be able to resolve
the host's link-layer address.

> 2) Do we have to make any recommendation regarding MLD joins when layer-2
 > hints are received whether there is a link change or not? (due to the
> presence snooping switches)

A host SHOULD always join MLD groups, after it receives a link-UP hint
on a new point-of-attachment.

Until it does so there is no guarantee that it can receive packets
addressed to its solicited nodes' addresses.  This means that it
may not be able to see DAD NS probes or neighbour resolution attempts
until it has done so.


Comments?

Greg