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I dont understand whether all ports in a switch are addressable by MAC. I see conflicting answers on the web - https://learningnetwork.cisco.com/thread/15380 and http://www.techexams.net/forums/ccna-ccent/45578-mac-address-switch.html .

I do understand that the answer maybe different for different manufactures and the layer at which the switch operates. But since a switch is primarily a layer 2 device, all its ports should be addressable. Is this correct?

karmanaut
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1 Answers1

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There are many reasons to not address ports of switch by MAC.

  1. MAC number is stored in hardware (read-only memory card). If each port address by its own MAC, it also has own ROM card => more money on hardware

  2. More complicated when you config MAC address table of switch manually.

  3. Exhaust MAC address resource faster, then you have to register another OUI number (Organizationally Unique Identifier)

You can see an example of MAC address table of a Cisco switch below:

VLAN      MAC Address       Type    Age       Port
---------+-----------------+-------+---------+--------------
1         0018.b967.3cd0    dynamic 10        Eth1/3
1         001c.b05a.5380    dynamic 200       Eth1/3

So you don't need separately MAC address for each port to make your switch work.

Dai Nguyen-Van
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