[c-nsp] Multicast source question

[Phil Mayers]

Michael Robson wrote:
> a source only. Is this true, or does the server set the destination MAC to
> the multicast MAC that corresponds to the multicast IP (which an ethereal

It's not true. The destination MAC address is the multicast L2 MAC.

> capture seems to be suggesting)? If this is true, then what is the process
> that gets the stream to the router, i.e. how does the switch determine that
> it should add the corresponding multicast MAC to the port facing the router?

The "router port" bit of IGMP snooping. Broadly speaking, when the 
switch sees IGMP queries coming in on a port, it marks that port as a 
router port and floods all multicast traffic up it.

> 
> Could any answers please be copied to my direct email as well as the list,
> as I only get digests.
> 
> 
> Thanks,
> 
> Michael.
> --
> Michael Robson,           | Tel:  0161 275 6113
> Networks,                 | Fax:  0161 275 6040
> University of Manchester. | Email: Michael.Robson at manchester.ac.uk
> 
> Youth and skill are no match for experience and treachery. 
> 
> 
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