Switching

[abdul.qadir5001]

How different MAC addresses can be learn against single port.

[Seb Rupik]

Hi there,

A MAC address is learnt by either a traffic flow passing through the port, or the post listening to ARP traffic on the connected segment.

cheers,

Seb.

[abdul.qadir5001]

Dear Seb Rupik,

Thanks for your response.You are right but with one switch port only one device can be connected. How a single switch port can learn multiple mac address as depicted in the picture.  

Also the number of ports on the switch is equal to number of mac address entries in the mac table?

Every switch port has its own mac address. Does it include in the mac address table entry?

[Seb Rupik]

As @Joseph W. Doherty , you probably have another switch connected to Gi1/0/1.  Or maybe an ESXi server, or maybe an Access Point?

I a very simple switch deployment with a single host connected to each switchport you would see a 1:1 ratio between dynamic MAC address and switchport. However it is more likely to see scenarios where these two numbers do not match.

You will only ever see a switch MAC address appear in the table if it has a layer 3 interface configured. When just switching the interface BIA is never used.

cheers,

Seb.

[Joseph W. Doherty · Accepted solution]

If a single port was has multiple devices "downstream" of even a single port, e.g. like a hub or switch with hosts connected to them, it may learn of multiple MACs.