[c-nsp] Multicast MAC address

[Phil Mayers]

On Fri, 2007-06-29 at 10:43 +0530, Vikas Sharma wrote:
> Hi,
> 
> Need help to understand the concept of multicast?
> 
> My question is what is the mac address, when a packet is forwarded across
> the WAN? Is it the mac address of connected router (unicast mac address) or
> multicast mac-address? When L2 and L3 mac address are in use in LAN and WAN
> scenarios?

It's the multicast MAC. GigE router-router p2p links are "just another
ethernet" as far as the packet formats go; they just happen to have
routes pointing down them.

(This means if your p2p actually goes via a L2 switch, you will likely
need PIM snooping on that switch)