sh arp/sh mac-address table

[karimbruxelles]

Hi,

Can someone explain me what is the difference between these 2 commands, they provide the same output Mac adress, I did not get why we have 2 differents kind of commands

Please advise

Regards,

[pkhatri]

Hi,

The difference is the 'sh arp' displays a cache of MAC addresses that have been resolved by L3 devices in the processing of determining the MAC address that corresponds to a given IP address, whereas the mac-addres-table displays the MAC addresses that are learned by a L2 switching device on each interface.

The first command applies to a L3 device and the second to a L2 device.

Hope that helps - pls rate the post if it does.

Paresh

[karimbruxelles]

Thx very much, it was very helpful

karim

[Richard Burts]

Karim

The explanation of your question is that the MAC-address table is built by the switch operating at layer 2 to support layer 2 forwarding by the switch, while the ARP table is built by layer 3 processing of the MSFC or the router to support layer 3 forwarding of IP packets. Additional differences are that the MAC-address table is built by passivly listening to incoming traffic and associating the source MAC address with the port that it arrived on. The ARP table is built more actively since when the MSFC or router needs to forward to an IP address and the MSFC or router does not already know the MAC address it will send an ARP request to learn the proper MAC address.

HTH

Rick

[karimbruxelles]

Very good explanation thx a lot

Karim