Unanswered Question
Mar 14th, 2008
User Badges:

Explanations Required...

1-Every Ethernet port + SVI's has a separate MAC address. Agreed ?? If yes, how every New created SVI get its mac address from

2-Every Ethernet interface of router also has its mac address and serial port doesnt have any.The N/W towards an ethernet leg of a router will have the MAC address of that ethernt interface in its arp table for that router.AND what about the network on its serial interface. What that network has in mac table against that router's IP?

3-Additionally what is the default arp timeout in cisco 3750 ?

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Istvan_Rabai Fri, 03/14/2008 - 12:28
User Badges:
  • Gold, 750 points or more

Hi Munawar,


It is not true that every Ethernet port has a separate mac-address. Layer 2 Ethernet ports don't have it. Only Ethernet ports configured for layer 3 operation have a mac-address.

Mac-addresses are given to the Ethernet intefaces and SVIs from a pool of internal mac-addresses of the switch or the supervisor engine.


Serial ports do not have a mac-address.

In case of point-to-point connection layer2 addresses are not necessary, as packets can be destined only to one destination: the other end of the link.

In case of multipoint frame-relay connections, serial interfaces use the frame-relay dlci as a layer2 address.

The dlci is specific to frame relay and identifies the frame-relay virtual circuit leading to the destination.

In frame-relay, the ip address - to - dlci mapping is similar to the ip address - to - mac-address mapping in the ARP table.

For your 3rd question I do not know the answer.




This Discussion