Thread: switch mac address learning

Hi all, am i right in saying that if I had 2 switches plugged together, each switch wouldnt know about each others mac addresses until a host is passed through the uplink, can anyone tell me how the switch knows to use the uplink to find the yet un found mac address, does the switch forward the broadcast from the pc, then its learnt ?

You are right - they do not communicate their MAC tables to each other. The time a switch learns about a device connected to another switch is when a packet hits *that* switch. Normally a broadcast will be carried across all switches in the VLAN, so when a PC arps, all switches will hear about it and add it to their tables. If after (by default) 5 mins, no traffic from said device hits the switch, it wll be removed from te table (cam aging)....