Ethernet multicast query
Posted on 2011-10-05
Just a quick question guys, maybe somebody can answer...
i know that the idea of multicast versus broadcast is to reduce the traffic that is sent over the LAN. If for example, my router sends out an EIGRP message to layer 3 multicast address 220.127.116.11, in theory this should be processed by other hosts on the LAN which are listening on that layer 3 address, that's fine, i get that.
i was just wondering how the corresponding layer 2 behaviour is dealt with? i assume there would be a corresponding layer 2 Ethernet address, and if so, how would the LAN switches forward the frame? i know a broadcast to ffff.ffff.ffff would forward out of all ports. does the frames with multicast destination addresses do the same, or just forward out of specific ports?
i can't seem to find the answer in my google searches.
thanks in advance.