CDP Problem

[andresfaraque1]

Hello.

I´m having a problem with mi LAN becase i´m seeing with CDP devices that are not connected directly:

Device A ------ SW CISCO A------ SW CISCO B

I´m seeing the Device A with CDP in my SW B.

SW CISCO A#show ver
Cisco IOS Software, C2960 Software (C2960-LANBASEK9-M), Version 12.2(55)SE11, RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2016 by Cisco Systems, Inc.
Compiled Wed 17-Aug-16 13:46 by prod_rel_team
Image text-base: 0x00003000, data-base: 0x01900000

ROM: Bootstrap program is C2960 boot loader
BOOTLDR: C2960 Boot Loader (C2960-HBOOT-M) Version 12.2(44)SE6, RELEASE SOFTWARE (fc1)

Any idea of what is my problem??

Thank you.

Andrés.

[Hulk8647]

you sure you're not stacking these?
can you provide the below
#sh cdp neigh detail

[andresfaraque1]

Sure.

File attached.

And no, i have no stack in my SW.

Andrés.

[Georg Pauwen]

Hello,

is this a live or a simulated network ? Post the output of 'debug cdp packets' ...

[andresfaraque1]

Hello Georg, is a Live.

Debug Attached

Andrés.

[Hulk8647]

Well, what is Device A? What is it's MAC address?

From Cisco A and B can you provide:

#show mac address-table

[andresfaraque1]

Hello Hulk8647

My devices are:

Switch A -> WS-C2960-48TC-L

Switch B ->  WS-C6506-E

File attached.

Andrés.

[andresfaraque1]

I tried to disable CDP in one port and this is the  result:

SWITCH A#show cdp nei fastEthernet 0/19
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
                  D - Remote, C - CVTA, M - Two-port Mac Relay

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
CVTA             Fas 0/19          147               H    Associate Port 2
SEP8851FB82428D  Fas 0/19          86               H P   Communica Eth 11

In SWITCH A i disable de CDP:


interface FastEthernet0/19
 no cdp enable

cosabog13l2715#show cdp nei FastEthernet0/19
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
                  D - Remote, C - CVTA, M - Two-port Mac Relay

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID


But in my SWITCH B, i´m still receiving the CDP of the Device that is connected to the Port 19 in SWITCH A.

COSABOG13SWL301#show cdp nei GigabitEthernet3/7 | i 428D
SEP8851FB82428D  Gig 3/7           164              H P   Communica Eth 11

[Hulk8647]

did you clear your CDP on the switch B after disabling CDP? I believe the default timeout for CDP is 180 seconds. If its still disabled and you haven't enabled it, I would check now. Or, you can use "clea cdp table"

[andresfaraque1]

Hello,

Yes, I clear the table in Switch B when I disable the CDP in Switch A

SWITCH B#clear cdp  table

SWITCH B#clear cdp  counters

SWITCH B#show cdp nei gi 3/7
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
                  D - Remote, C - CVTA, M - Two-port Mac Relay

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
CVTA             Gig 3/7           179               H    Associate Port 1
CVTA             Gig 3/7           179               H    Associate Port 2

A couple of seconds later...

SWITCH B#show cdp nei gi 3/7
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
                  D - Remote, C - CVTA, M - Two-port Mac Relay

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
CVTA             Gig 3/7           179               H    Associate Port 2
CVTA             Gig 3/7           179               H    Associate Port 1
SWITCH A      Gig 3/7           175              S I   WS-C2960- Gig 0/2
SEPD4C9EFDEBFD8  Gig 3/7           158              H P   Communica Eth 11
SEP8851FB82428D  Gig 3/7           145              H P   Communica Eth 11  -------> Port Fa0/19 in SWITCH A
SEP40A8F0A3EDBD  Gig 3/7           115              H P   Communica Eth 10
SEPD4C9EFD4AEDD  Gig 3/7           157              H P   Communica Eth 17
SEPD4C9EFD62A1C  Gig 3/7           168              H P   Communica Eth 11
SEP40A8F0A3EDE9  Gig 3/7           157              H P   Communica Eth 10
SEP40A8F0A3F295  Gig 3/7           145              H P   Communica Eth 10
SEP40A8F0A4C164  Gig 3/7           155              H P   Communica Eth 11
SEPD4C9EFD4AFD0  Gig 3/7           157              H P   Communica Eth 11
SEP40A8F0A431C4  Gig 3/7           157              H P   Communica Eth 10
SEPD4C9EFD4AE3E  Gig 3/7           143              H P   Communica Eth 11
SEPD4C9EFD6A310  Gig 3/7           158              H P   Communica Eth 18

But in my Switch A CDP don´t show nothing...

SWITCH A#show cdp nei fa 0/19
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
                  D - Remote, C - CVTA, M - Two-port Mac Relay

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
SWITCH A#

Andrés.

[Hulk8647]

you have physically verified the cabling between these switches ?

[andresfaraque1]

Hello,

Yes, is Fiber

NAME: "GigabitEthernet0/2", DESCR: "1000BaseSX SFP"

Andrés.

[Hulk8647]

could you provide show run of both switches ?

[cofee]

This link doesn't specifically answer you question, but you may find it useful for some of the findings you have come across during the troubleshooting steps.

https://supportforums.cisco.com/t5/lan-switching-and-routing/cdp-neighbours/td-p/2485786

[andresfaraque1]

Hello Cofee.

Thank you, but is not my case, all my SW are cisco.

Hulk8647:

File attached with the config

Andrés.