ISE 4331 with 4 port SW module, CDP not working why ?

[parag_waghmare]

Hi Community,

I have ISR 4331 with 3.16 IOS-XE with 4 port switch module ("NIM subslot 0/1", DESCR: "NIM-ES2-4").

Router acting as layer 3 switch.

The downstream access switch connected to port Gi0/1/0 on the Switch module is not seen as cdp neighbour on the ISR

But, on the access switch 3750X, it can see the ISR 4331 as cdp neighbour.

What could be the reason ?

[Leo Laohoo]

CDP turned off on the port?

[parag_waghmare]

hi Leo,

thanks for responding.

No CDP is turned ON on interface.

[Leo Laohoo]

Well CDP is a two-way traffic. Is CDP turned on in BOTH ends?

[parag_waghmare]

yes it is, and that's the weird bit. the 3850 access switch sees the ISR 4331 as CDP neighbour, but the ISR does not see the acccess switch on CDP on the SW module port.

Code : System image file is "bootflash:isr4300-universalk9.03.16.05.S.155-3.S5-ext.SPA.bin"

SW module : NAME: "NIM subslot 0/1", DESCR: "NIM-ES2-4"
PID: NIM-ES2-4 , VID: V01, SN: FOC204683YU

Interface Config on ISR going to access switch :

wsr-shiel :

!
interface GigabitEthernet0/1/0
description sw-shiel-1 Gi1/0/24
switchport trunk native vlan 980
switchport trunk allowed vlan 900,901,1100,1150,1200,1250,1300,1400,1500,1600
switchport trunk allowed vlan add 1700,2500
switchport mode trunk
switchport nonegotiate
spanning-tree portfast disable
spanning-tree link-type point-to-point

CDP run configured globally

cdp enable done on port.

*********************************

On access switch. :

sw-shiel-1#sh cdp ne
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
wsr-shiel.unimelb.net.au
Gig 1/0/24 146 R S I ISR4331/K Gig 0/1/0

Interface config on uplink interface :

sw-shiel-1#sh run int Gi1/0/24
Building configuration...

Current configuration : 383 bytes
!
interface GigabitEthernet1/0/24
description wsr-elc Gi0/0/1
switchport trunk encapsulation dot1q
switchport trunk native vlan 980
switchport trunk allowed vlan 900,901,1100,1150,1200,1250,1300,1400,1500,1600
switchport trunk allowed vlan add 1700,2500
switchport mode trunk
switchport nonegotiate
spanning-tree portfast disable
spanning-tree link-type point-to-point
end

[Leo Laohoo]

Hmmmm ... Can you try shut/no shut the port and see if this helps.
This sounds like CSCvo22398.

[parag_waghmare]

Tried that Leo. Tried debug CDP, but there seems to be CDP silence on the ports on that SW module.

[Leo Laohoo]

Raise a TAC Case. This could indeed be very similar to CSCvo22398.

[parag_waghmare]

Thanks Leo for responding.