What is the task of an Ethernet switch? What tables does it maintain?

Question

What will be an ideal response?

Answer 1

An Ethernet switch must maintain routing tables giving the Ethernet addresses and network id for all hosts on
the local network (connected set of Ethernets accessible from the switch). It does this by ‘learning’ the host
addresses from the source address fields on each network. The switch receives all the packets transmitted on
the Ethernets to which it is connected. It looks up the destination of each packet in its routing tables. If the
destination is not found, the destination host must be one about which the switch has not yet learned and the
packet must be forwarded to all the connected networks to ensure delivery. If the destination address is on the
same Ethernet as the source, the packet is ignored, since it will be delivered directly. In all other cases, the
switch tranmits the packet on the destination host’s network, determined from the routing information.