4500x vss no cdp neighbors

[snir_orlanczyk]

Hi, 

i have 2 4500x connect via VSS . they r currently the aggregation layer at my network and have other cisco switches connect to them.

the issue im having is when i type show cdp neighbors  there are no entries at all.

everything is working fine, traffic is flowing. but i just cant see the other switches  on cdp.

my device is WS-C4500X-16

and im running this version: 03.06.01.E.152-2.E1

[Mark Malone]

hi

is cdp turned on ?  cdp run turns it on globally

lldp run will also pick up the switches its vendor independent cisco are moving to this on lot of newer platforms like 9ks

[snir_orlanczyk]

there has been a small mistake in my description.

the 4500x can see his cdp neighbors... but his neighbors  cant see him but they can see other devices.

i've used debug cdp packets and saw that the end switch (3750x is the one im doing my tests on) does not receive any cdp packets from the 4500x.

it worked fine until a while ago.

any ideas?

thanks alot for the help.

and sorry for the misinformation, and also i've been told that that lldp works fine, although they want to work with cdp

[Mark Malone]

That sounds like a bug unless your blocking port 4224 between the switches which is unlikely as its working on 3750 side

especially that lldp is working fine and cdp only works one way , if its not been blocked something's gone wrong in software on 4500x and its not giving out its cdp info

you could try to enable it per interface as well incase its a global cdp issue bug

your also on an ED 3.6.1 release which can be susceptible to bugs I would try move to the MD release 3.6.4E(MD)  see if that resolves it for you

[paul driver]

Hello

Try LLDP instead

res

Paul

[snir_orlanczyk]

first of all thanks a lot for the help,

but upgrading the system is not really an option unless im sure that there's a bug causing this problem, and i didnt manage to find a bug referring my issue in the cisco bug search tool.

also paul, thanks for the help but has i mentioned LLDP works, but its i need a soultion or a pointer at least for the CDP issue.

thank you :)

[paul driver]

Hello

Can you do a cdp comparison check between the two devices .

sh cdp

sh cdp interfaces

res

paul

[Mark Malone]

Hi

these 4500x images have a lot of bugs especially the ED releases just because its not registered does not mean you have hit one even the behaviour of it resembles a bug , if cdp is on and nothings blocking it there ios no reason switch should not see it unless something in software is not allowing it

have you tried to enable it per interface still the same ?

Have you tried to debug cdp events and packets on 4500x side , is it trying to communicate with 37 does it show anything ? you should see if its working its trying to communicate with 3750 you should see 3750 name in debug and it should show src interface and mac etc can you post it

[Mark Malone]

did you get any further with this , just interested to see how it turned out , if the cdp info is showing in debugs even ?

[snir_orlanczyk]

i tried using a sniffer to see if the 4500x has sent any cdp packets ,and received 0 cdp packets.... right now the general assumption is that we are having a bug.

we also tried rebooting the switchs (one at a time, they are working in vss).

and disabling and enabling the cdp on specific ports.

we are trying to look into the bugs a bit more. because we have 7 more switchs like that are running the same version and have no problem (im aware that a bug might effect only this switch), but changing this switch version means changing all of the switchs version, so im not really rushing towards that solution.

thanks for helping! you gave same really good points that helped me a lot !!

[Mark Malone]

thanks for letting me know , yes understand not wanting to upgrade all devices when prod , if you have support TAC will tell you straight away if there's a bug on that version , not everything is in the release notes it does not be updated as frequently as it should ,TAC would have a lot more info than whats available to the public