Is There a Layer 2 Address Advertising Protocol?

cdplayer2layer3lldpmac address

I needed help in understanding if LLDP/CDP is the Layer 2 equivalent to RIP or say any Layer 3 route advertising protocol. If not,is there a protocol that advertises the MAC Address Tables among switches?

Best Answer

LLDP is not a layer 2 equivalent of RIP.

RIP is a routing protocol, advertising routes between routers.

LLDP is a device discovery protocol, so neighboring devices can learn about each other.

Switches make their forwarding decisions independently, so there is no need to advertise MAC address tables between them.

Related Solutions

MAC Address – How to Trace on a Switched LAN

If you have an end-to-end vlan topology, where vlans are not terminated on switches, you can use somethink like this algorithm:

On the root switch get the mac address table, use filter output:

sh mac add | i 8a06

1    0015.5d02.8a06   dynamic ip,ipx,assigned,other TenGigabitEthernet4/5

Now you know, that mac is behind interface TenGigabitEthernet4/5. Connect to the switch behind this interface, and repeat sh mac add | i 8a06. You will find your host in the end.

Switch – Why each and every single port on Layer 2 switches need to have it’s own MAC address

One key use for per port MAC addresses on switches is for Spanning-tree BPDU's. These are Layer-2 multicasts with source MAC address of the egress switch port.

I would have to brush up on other Layer-2 protocols such as TRILL and SPB, but they might also take advantage of a per port MAC.

Does that help?

Best Answer

Related Solutions

MAC Address – How to Trace on a Switched LAN

Switch – Why each and every single port on Layer 2 switches need to have it’s own MAC address

Related Topic