dslreports logo
 
    All Forums Hot Topics Gallery
spc
Search similar:


uniqs
329

Medievall
@12.13.x.x

Medievall

Anon

Interface Mac address

Q1:
How many Mac addresses normally can an interface like FastEthernet and GigabitEthernet have?
I saw on my network the FE have 2 while the Giga Ports have more than 10.

Q2:
my understanding is that an interface only need one mac address, what do the extra mac address use for?

thanks
MousePad
join:2005-01-08
Jonquiere, QC

MousePad

Member

Hello Medievall

Q1: Where did you get this information? If you got it from the "show mac-address-table" command, that is not the MAC addresses associated to that port, it shows the MAC addresses learned for the different ports, ie how the switch will direct traffic based on MAC addresses in the packet header. In fact, I checked on a 3550 and a 3750, I don't think it's possible to add a MAC address to an interface.

Q2: One use that comes to mind would be in a server cluster. That's the way the servers in the cluster are able to process the "same" traffic coming from workstations. On a switch though, I can't figure out any use. Anybody?

Hope this helps

Medievall
@12.13.x.x

Medievall

Anon

Hi, Mousepad:
tahnks,
This information is listed on our documents.
So you dont think that an physical interface can be associated with two or more mac addresses?
am i understanding correct?
thanks,
M
MousePad
join:2005-01-08
Jonquiere, QC

MousePad

Member

Hello Medievall...

It does not seem so.. And yes, you understand correctly I tried to find a command that would enable me to do it on a switch, and I couldn't... And as I said, what would be the purpose?

The switchport is nothing more than that... It does not provide any service to users, it just sends and receives packets, based on what is happening in the switching fabric... So there is no point in assigning it more than one MAC address.

The use of multiple MAC addresses on a physical ethernet interface would only make sense on a server, in the scenario I mentioned in my previous post.

Hope this helps