Are there any CDP Specification on the Cisco891F or 891FJ switchport?

[mhiyoshi]

Dear Support all,

Well I have the following simple test however I can not figure out why CDP configuration change from no cdp enable or cdp enable on the Cisco891FJ switchport after that the counter switch device always happen link flapping. However when it configures no cdp run/cdp run or routed port or Cat2960X - Cat3560G switchport does not occur. So I think it is just Cisco891F or Cisco891FJ CDP specification but there is not any information on the related release note or CCO documents so I appreciate if you can let me know your precious opinion or related URL (CCO or related) much better. Here is the test result.

■TEST1-Cisco891FJ-Gi0-----Gi0/1--Cat2960X
■Result: LinkFlap Occured on the Cat2960X

C891FJ(config)#int gi0
C891FJ(config-if)#no cdp enable

Cat2960X#
Mar 7 09:45:28.774: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to down
Mar 7 09:45:29.781: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to down
Mar 7 09:45:33.297: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up
Mar 7 09:45:34.300: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up

C891FJ(config)#int gi0
C891FJ(config-if)#cdp enable

Cat2960X#
Mar 7 09:51:06.535: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to down
Mar 7 09:51:07.541: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to down
Mar 7 09:51:11.022: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up
Mar 7 09:51:12.022: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up

■TEST2-Cat3560G-Gi0/2-----Gi0/2--Cat2960X
■Result: Link connection keeps UP/UP

Cat3560G(config)#int g0/2
Cat3560G(config-if)#no cdp enable
Cat3560G(config-if)#cdp enable

Cat2960X#sh ip int brief | in up
GigabitEthernet0/2 unassigned YES unset up up

Best Regards,

Masanobu Hiyoshi

[Peter Paluch]

Hello Masanobu,

It might be possible that you are hitting the defect CSCuj03257:

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCuj03257

Would it be possible for you to test out one of the fixed IOS versions shown on the page above? Please let us know. Thanks!

Best regards,
Peter

[mhiyoshi]

Hello Peter,

That would be great support! Thank you very much.

But according to the CSCuj03257, I think that are the release below.

CSCuj03257:
Affected : 15.2(4)M4.3
Fixed    : 15.2(4)M5.1, 15.3(3)M3 etc.

However the Tested version is 15.4(3)M8 or 15.6(3)M0a

So this is related but not the exact one right?

Best Regards,

Masanobu Hiyoshi

[mhiyoshi]

Hello Peter,

I have verified the following IOS-Version however the fixed version still can happen the linkflap.

And as for 15.6(3)M0a when it configures "cdp run" also can happen it.

IOS-Ver.15.3(3)M3 *It is supposed Fixed Version.

no cdp run -> Normal
   cdp run -> Link Flap

no cdp enable -> Link Flap
   cdp enable -> Link Flap

IOS-Ver.15.6(3)M0a is same result (Re-Verified)

Best Regards,

Masanobu Hiyoshi

[sbhadrav@cisco.com]

You cannot enable/disable CDP on an interface unless it is enabled globally using the cdp run command.
You can disable cdp on an interface by using the no cdp enable command. In that case, the interface won't process CDP neither send CDP frames out.If you don't want to run CDP at all, use no cdp run at global configuration mode..
Another thing, do you have any other switch models (like a 2960X)?  The reason why  is because this is beginning to smell like an IOS bug. If you have a switch that is capable of loading IOS version 12.2(55)SE8 or 15.0(2)SE4 then I'd be keen to know what the behaviour is like.  Same cable going to the 3750X, same ports.  The only thing different is the IOS version.  EXn-series IOS is an interim version software.