Mac-address table build up

[rajesh shet]

Hi,

i want to know what are the packet types a switch considers to build a Mac-address table.

Does it consider packets like ARP (query & response) & DNS (query & response) to build its mac-address table ?

[Rohan Sonawane]

Hello Rajesh,

A switch works on L2 logic. For switch it doesn't matter whether its an ARP packet or DNS packet or OSPF packet, or any other packet. As long as a packet contains an Ethernet header, the switch will build its MAC table based on the frames' source MAC address.

For example, if a packet is received with source MAC add A and destination MAC add B on F0/1 interface, the switch will build its MAC table - irrespective of type of the packet.

MAC table is also called CAM table ( Content addressable memory).

Regards,

Rohan.

[rajesh shet]

Thank you Rohan.

I agree and thats what i assumed however there was a an article which i had come across which mentioned that arp packet source mac address are ignored by switches.

[Rohan Sonawane]

Hi Rajesh,

Can you provide link for that article?

May be the article was written in different context? May be it was referring to port-security?

Or else I have not read anywhere about a Cisco switch ignoring source MAC in ARP packets.

Regards,

Rohan.