CDP Neighbor Detail

[r.volante]

Hi All,

Show cdp neighbor details show that it is communicating via Vlan 7(192.168.1.x). From my checking, this vlan is not in use and client is asking if we can strip off. But since the CDP neighbor is somehow getting this IP address, I am kind of hesitant what the effect of removing it would be.

connection is simple. Core Switch  ßà Access Switch. Snippets of Logs are attached below.

Core Switch CDP

Access switch CDP

What would be the effect of removing VLAN 7 for both the core and the access switch?

Regards

[balaji.bandi]

how is your network connected, that output not showing accurate information here.

where VLAN 7 showing in that output (am i missing anything?)

Do you have VTP Server running in the network ?

can you post below output : (attached text not screenshot)

show cdp neigh (from both)

show vtp status (both)

show spann brief (both)

show vlan 

show ip interface brief

[MHM Cisco World]

CDP is L2 not L3 protocol'

It exchange between two SW if it direct connect even if both SW dont have IP.

MHM

[MHM Cisco World]

https://community.cisco.com/t5/routers-small-business/how-does-cdp-choice-the-ip-of-it-s-neighbor/td-p/1574570

above link is useful to understand how CDP elect the mgmt IP (some old SW dont support hardcode the mgmt IP of CDP sorry)
MHM

[MHM Cisco World]

if the SW dont have IP for VLAN1 then it will select the IP of VLAN that have the lowest VLAN ID

I run lab and test remove the IP of VLAN1 and see how SW elect the mgmt IP it elect IP for VLAN2 not VLAN10 (NOTE lowest VLAN ID not VLAN NAME)

[paul driver]

Hello
CDP will Always choose vlan 1 or the lowest active vlan other than vlan 1 , So deleting a vlan will not necessary affect the active mgt vlan of the switch to gain remote access to it.

so if vlan 7 is not used for anything you can safely remove it.