Switching

[carl_townshend]

Do switches use purely the processor or caching etc ?

[a-larkins]

all depends really mostly a combination of both - if cef is enabled, then the forwarding decision is made there. DFC card push the FIB tables to the line cards in the larger switches so that the lookup does not go to the CPU and cause an interupt

[carl_townshend]

i gather the mac address table is in memory so anything on the same lan doesnt need to be processed as it will look at the mac table ? is this correct ?

[ankurbhasin]

Hi Carl,

Keep sweet and simple explaination if you talk of pure simple layer 2 switch , then yes switching is done in ASIC (application specific integrated circuit) i.e all hardware.

If any frame hits the switch , it checks the destination mac address from mac address table and if found it is switched in asic to the destined port.

HTH, if yes please rate the post.

Ankur