ARP

shelley_wang · ‎09-23-2010

Hi,

PC and switch use ARP to discover the destionation MAC address. When a packet reaches routers, do routers use ARP to discover the next hop router's MAC address?

thx,

Jingyi

Julio Garcia · ‎09-23-2010

Yes , you are correct

otherwise router will not be able to send frames to next hop.

Maximiliano Gustavo Menendez · ‎09-23-2010

Hi, just to clarify a little more.

"PC and switch use ARP to discover the destionation MAC address...."

This is not right. PC use ARP to find out the destination MAC (of the gateway or other PC on the same LAN), but switches doesn´t. Switches use the source MAC address of any packet to fill its mac-address table, and if the destination MAC of a packet is not present in the mac-address table, the switch just flood this packet out of all its ports where the vlan is permitted (access or trunk).

Hope it helps...

Regards,

Max