|
Posted by Albert Manfredi on June 12, 2008, 10:25 am
If you were Registered and logged in, you could reply and use other advanced thread options
> No i m taking about the enteries made in layer 2 switch in its
> multicast table is what , either it static or dynamic.
What entries?
Take a normal, non-snooping L2 switch. A MAC frame with multicast MAC
DA arrives at the switch. The default behavior is what? It is to flood
that multicast frame to all active ports. No tables needed.
What node created that MAC multicast DA to begin with?
It was the host that originally transmitted the frame. If that host
was sending out multicast IP packets, *it* would be the box that maps
the IP Class D to the appropriate MAC multicast DA.
Does the L2 switch know anything about the IP DA, assuming the MAC
frame is carrying IP? No, because I said at the top that this was a
normal, non-snooping L2 switch. It knows nothing about Layer 3.
So are there any multicast table entries at all? Only if the switch
does either IGMP snooping, or GMRP.
If the L2 switch does IGMP snooping, then read RFC 4541 to see about
timeout timers.
Bert
| 
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML site map