4948-10GE - show CDP neighbour's neigbour problem

Trifid · 10 Jun 2010 at 13:34

Not a major issue but annoying none the less...

We have a few 4948-10GE running IOS 12.2(31)SGA7 (upgraded from a slightly earlier IOS which had the same problem) where the cdp neigbour progresses 2 hops down the line instead of its 1 hop neighbour.

For example on a Cisco 3550 we get the following displayed (with some stuff removed)

SW01 Gig 0/1 WS-C4948- Ten 1/49
SW02 Gig 0/1 WS-C4948- Ten 1/49
Core Gig 0/1 WS-C6509- Gig 2/24 (it's actual neighbour)

Anyone else have this problem?

bigredshark · 11 Jun 2010 at 15:04

The 6509 isn't doing MPLS by any chance is it? Our boxes don't seem to like CDP and MPLS, all sorts of neighbours keep turning up...

Trifid · 11 Jun 2010 at 15:28

Nope. It is a collapsed core, just connecting all the access switches and server switches and doing the vlan routing, nothing special. There are 2 of them, redundantly connected with HSRP for the vlan routing. The CDP problem appears on the gig 0/2 (to the secondary core).

bigredshark · 11 Jun 2010 at 15:42

Trifid said:
Nope. It is a collapsed core, just connecting all the access switches and server switches and doing the vlan routing, nothing special. There are 2 of them, redundantly connected with HSRP for the vlan routing. The CDP problem appears on the gig 0/2 (to the secondary core).

Interface config?

Trifid · 11 Jun 2010 at 15:49

3750 stack (same for the other redundant link):
interface GigabitEthernet1/0/1
switchport trunk encapsulation dot1q
switchport trunk native vlan *removed*
switchport mode trunk
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
queue-set 2
mls qos trust cos
auto qos voip trust

6509-V-E:
interface GigabitEthernet2/8
switchport
switchport trunk encapsulation dot1q
switchport trunk native vlan *removed*
switchport mode trunk
wrr-queue bandwidth 5 25 70
wrr-queue queue-limit 5 25 40
wrr-queue random-detect min-threshold 1 80 100 100 100 100 100 100 100
wrr-queue random-detect min-threshold 2 80 100 100 100 100 100 100 100
wrr-queue random-detect min-threshold 3 50 60 70 80 90 100 100 100
wrr-queue random-detect max-threshold 1 100 100 100 100 100 100 100 100
wrr-queue random-detect max-threshold 2 100 100 100 100 100 100 100 100
wrr-queue random-detect max-threshold 3 60 70 80 90 100 100 100 100
wrr-queue cos-map 1 1 1
wrr-queue cos-map 2 1 0
wrr-queue cos-map 3 1 4
wrr-queue cos-map 3 2 2
wrr-queue cos-map 3 3 3
wrr-queue cos-map 3 4 6
wrr-queue cos-map 3 5 7
mls qos trust cos

bigredshark · 11 Jun 2010 at 15:50

Looks like it should work, what about the 4948 config - you're not doing q-in-q by any chance?

bigredshark · 11 Jun 2010 at 15:55

Actually, if you can, knock them up to a revision at or above 12.2.46 - there were some CDP/CDPv2 bugs fixed then as I recall...

Trifid · 11 Jun 2010 at 16:01

Very basic config on the 4948's, just a dot1q trunk and the native vlan changed on the 10gig ports. Nothing special like Q-in-Q.

We have a couple that we put in this week on 12.2(53)SG1 with the same problem.

Curiosityx · 16 Jun 2010 at 22:36

Your not running Layer 2 Protocol Tunneling anywhere on the network are you?

http://www.cisco.com/en/US/docs/swi...e/configuration/guide/swtunnel.html#wp1005050

TrX · 19 Jun 2010 at 19:09

Curiosityx said:
Your not running Layer 2 Protocol Tunneling anywhere on the network are you?

http://www.cisco.com/en/US/docs/swi...e/configuration/guide/swtunnel.html#wp1005050

Any output from:
sh run | include l2protocol-tunnel

on the magical missing switch??

//TrX

Trifid · 19 Jun 2010 at 20:51

TrX said:
Any output from:
sh run | include l2protocol-tunnel

on the magical missing switch??

//TrX

I was sure I replied to this question. :/ Must have not submitted the reply. There isn't any L2 protocol tunnelling.

The switch isn't missing, it can see the CDP information too.