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A core switch CANNOT see a WS-C2960S-48TS-S when i do show cdp neighbor.

Jacob Gwangwa
Level 1
Level 1

Hi there.

I'm having a strange issue here. I just installed a WS-C2960S-48TS-S and connected it to the core switch WS-C6509-V-E.

CDP is enabled on both devices. When i do show cdp neighbor on my WS-C6509-V-E i cannot see the WS-C2960S-48TS-S in my neighbor table.

But on the WS-C2960S-48TS-S, when i do show cdp neighbor i can see the WS-C6509-V-E.

Note everything works fine its just that i'm worried as to why my WS-C6509-V-E cant see the WS-C2960S-48TS-S as its neighbor.

What i've tried thus far.....

on the interface level for both device cdp is enable and also in the global.

Please help me resolve this issue..

I would like to thank you in anticipation of your urgernt response

Regards,

Jacob

18 Replies 18

avrb-south-asw-8#config t
Enter configuration commands, one per line.  End with CNTL/Z.
avrb-south-asw-8(config)#int g0/49
avrb-south-asw-8(config-if)#sw
avrb-south-asw-8(config-if)#switchport t
avrb-south-asw-8(config-if)#switchport trunk ?
  allowed  Set allowed VLAN characteristics when interface is in trunking mode
  native   Set trunking native characteristics when interface is in trunking mode
  pruning  Set pruning VLAN characteristics when interface is in trunking mode

avrb-south-asw-8(config-if)#switchport trunk

This is as far i can go regarding the encapsulation dot1q on the 2960 Switch.

dont you perhaps suspect a bug because for this other switch WS-C2960G-48TC-L configurations are more the same and its visible in the 6509 cdp table.

because i dont undestand why the 6509 cant see the 2960. Everything is working normal. Like i said that users connected on this 2960 switch are working but just that its not in the 6509 cdp table if thats the word to put.

2960 by default supports Dot1Q trunking, since 2900 can see to 6500 but 6500 cannot..can you check by reloading 2900 Access switch in after office hours if same gets resolved..or it may be a bug as well...

Hi Alessio

I will log a change request for this.

I'll then have this switch (2960) with dual connection to the two 6509 as they are in VSS mode. After that i'll port-channel just like any other switches in the network and i'll revert with the outcomes.

thank you for your patience and help, much appreciated.

Regards,

Jacob

I first upgraded to c2960s-universalk9-mz.122-58.SE2 still my Core  couldnt see the 2960 but the 2960 can see the core.

I however upgraded to the latest ios c2960s-universalk9-mz.150-2.SE still same issue.

I really dont know if i should log a TAC or not. Or should i reboot the core (6509)- this is a switch in production of which my manager might have issue with this solution. The strange thing is everything is working. I have very critical servers connected on this 2960 switch and traffic is flowing. The thing is everyday i do show cdp neighbour to see if all my LAN switches are still up as we dont have any NMS to manage the network.

thanks in advance.

Jacob

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