Which MAC should be used: device MAC or Interface MAC?

My L3 switch has ~30 interfaces. If you look at the output below there are two MAC addresses showing in the results of the show interface command. The hardware address is the same for all interfaces. The physical address is different for each interface.

Assume that an IP address was configured on interface ce1/1. When ce1/1 receives an ARP request for the IP configured on it, which MAC should be used in the ARP reply?

What are the potential issues if I use the hardware address rather than the physical interface address? Is there any standard talking about this situation?

rtr1#sh interface
Interface ce1/1
  Scope: both
  Flexport: Breakout Control Port (Active): Break Out Enabled
  Hardware is ETH  Current HW addr: 4c76.2541.a6c1
  Physical:4c76.2541.a6f2  Logical:(not set)

  Interface ce1/2
  Scope: both
  Flexport: Non Control Port (Active)
  Hardware is ETH  Current HW addr: 4c76.2541.a6c1
  Physical:4c76.2541.a6f3  Logical:(not set)

Leave Your Comment

Leave a Reply

Which MAC should be used: device MAC or Interface MAC?

My L3 switch has ~30 interfaces. If you look at the output below there are two MAC addresses showing in the results of the show interface command. The hardware address is the same for all interfaces. The physical address is different for each interface.

Assume that an IP address was configured on interface ce1/1. When ce1/1 receives an ARP request for the IP configured on it, which MAC should be used in the ARP reply?

What are the potential issues if I use the hardware address rather than the physical interface address? Is there any standard talking about this situation?

rtr1#sh interface
Interface ce1/1
  Scope: both
  Flexport: Breakout Control Port (Active): Break Out Enabled
  Hardware is ETH  Current HW addr: 4c76.2541.a6c1
  Physical:4c76.2541.a6f2  Logical:(not set)

  Interface ce1/2
  Scope: both
  Flexport: Non Control Port (Active)
  Hardware is ETH  Current HW addr: 4c76.2541.a6c1
  Physical:4c76.2541.a6f3  Logical:(not set)

Leave Your Comment

Leave a Reply