Ive got a 3760 switch connecting via it's fa1/0/1 to a 3560 switch connecting on its fa 0/1.
the Base Ethernet MAC Address of my L3S1-3760 is : 00:13:1A:E8:DC:00
and Base Ethernet MAC Address of my L3S2-3650 is : 00:1B:2B:E5:14:80
However in the mac tables the last digit of the neighboring switch's mac address is changed from a '0' to a '3'
L3S2-3560#sh dtp int fa 0/1
DTP information for FastEthernet0/1:
TOS/TAS/TNS: TRUNK/AUTO/TRUNK
TOT/TAT/TNT: 802.1Q/NEGOTIATE/802.1Q
Neighbor address 1: 00131AE8DC03
fyi: output trancated
L3S1-3760#sh dtp int fa 1/0/1
DTP information for FastEthernet1/0/1:
TOS/TAS/TNS: TRUNK/ON/TRUNK
TOT/TAT/TNT: 802.1Q/802.1Q/802.1Q
Neighbor address 1: 001B2BE51483
fyi: output truncated
L3S1-3760#sh mac-
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
1 001b.2be5.1483 DYNAMIC Fa1/0/1
refer picture attached:
The Switch on the left, L3S1-3760 learns the MAC-address of the switch on the right as 001b.2be5.1483
Via the interface fa 1/0/1 from incoming frames sent by the switch on the right L3S2.
the base Ethernet MAC address of L3S2 is 001b.2be5.1480.
It however advertises its address as 001b.2be5.1483. The Last digit of the MAC address is changed from a
‘0’ to a ‘3’.
Both switches seem to have changed the last digit of their base mac address in their neighbor advertisements.
Why is that? Does DTP or some other protocol replace the last digit of the switch’s base MAC address with a code of some sort?
