What is Port-cpp in fdb tables?

[dgsong]

Hi everyone. Sometimes when I look at fdb tables when I can't communicate, it looks like Port-cpp, but after some time it changes to normal interface.

 

what is Port-cpp in fdb tables?

[WillyHe]

hello,

I guess "New Contributor III " has it correct, see examples copied from the "VOSS Users Guide".

SwitchG:1# show ip arp vrf blue
================================================================================
IP Arp - VRF blue
================================================================================
IP_ADDRESS MAC_ADDRESS VLAN PORT TYPE TTL(10 Sec) TUNNEL
--------------------------------------------------------------------------------
203.0.113.2 00:0e:62:25:a2:00 11 - LOCAL 2160
203.0.113.255 ff:ff:ff:ff:ff:ff 11 - LOCAL 2160
203.0.113.3 00:0e:62:25:a2:01 12 - LOCAL 2160
203.0.113.255 ff:ff:ff:ff:ff:ff 12 - LOCAL 2160
================================================================================
IP Arp Extn - VRF blue
================================================================================
MULTICAST-MAC-FLOODING AGING(Minutes) ARP-THRESHOLD
--------------------------------------------------------------------------------
disable 360 500
4 out of 50 ARP entries displayed

From the same switch:

SwitchG:1# show vlan mac-address-entry 11
================================================================================
Vlan Fdb
================================================================================
VLAN MAC SMLT
ID STATUS ADDRESS INTERFACE REMOTE TUNNEL
--------------------------------------------------------------------------------
11 learned 00:00:00:00:01:02 Port-1/2 false SwitchC
11 self 00:0e:62:25:a2:00 Port-cpp false -
2 out of 4 entries in all fdb(s) displayed.

From another switch:

SwitchC:1# show vlan mac-address-entry 11
================================================================================
Vlan Fdb
================================================================================
VLAN MAC SMLT
ID STATUS ADDRESS INTERFACE REMOTE TUNNEL
--------------------------------------------------------------------------------
11 learned 00:00:00:00:01:02 Port-1/2 false SwitchD
11 learned 00:0e:62:25:a2:00 Port-1/2 false SwitchD
2 out of 2 entries in all fdb(s) displayed.

[Configterminal]

I always understood it to be a MAC address owned locally by the switch.

[dgsong]

Thank you for your answer.
I modified the post so that the picture could be seen in the question.
The mac address is the mac address of another switch, but suddenly it changes from mactable to port-cpp, making it impossible to communicate. After a few minutes, it returns to normal port and communicates.

[Configterminal · Accepted solution]

Just speculating here but it almost sounds like you have a loop or a misconfigured LAG (SMLT in your case).  Is the downstream switch configured properly via it's LAG using LACP (or static alternative) to your v-IST cluster?