Fiber uplink on Catalyst 3560X shutting off (connected to 6509 core)

[ytanskiy]

I have a site which is connected to my core (6509) through a wireless link. Wireless equipment vendor checked their equipment and they are swearing that the issue is not on their end. Site is using Catalyst 3560X switch with fiber (100Base SX SFP) uplink connected to the wireless equipment. Image on the 3560X is C3560e-universalk9-mz.122-55.se3.bin. My problem is that from time to time, the fiber uplink shuts down, and we have to physically restart the 3560X for it to become operational. On top of it, when it happens, the port on 6509 also goes down with excessive errors and we have to disable/enable the port for it to become operational. Any ideas?

[Reza Sharifi]

Have you tested the fiber?

Are you using multimode cable end to end?

What is the distance between switches?

what is the part number for 100FX module?

[ytanskiy]

Checked the log on the 6509 and the port is getting errDisabled due to

Unidirectional Link Detection (UDLD). I will check on the fiber.

[Leo Laohoo]

If it's UDLD, then disable UDLD on both sides.

Post the BOTH outputs to the command "sh interface ".

On the 3560X, post the output to the command "sh controller e ".

[ytanskiy]

It looks like it is not the issue with the fiber, but the loop errors.

Dec 14 14:23:15: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0950.

Dec 14 14:23:16: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0001.

Dec 14 14:23:16: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down

Dec 14 14:23:54: %UDLD-4-UDLD_PORT_DISABLED: UDLD disabled interface Gi1/1, aggressive mode failure detected

Dec 14 14:23:54: %PM-4-ERR_DISABLE: udld error detected on Gi1/1, putting Gi1/1 in err-disable state

Dec 14 14:23:55: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/1, changed state to down

Dec 14 14:23:56: %LINK-3-UPDOWN: Interface GigabitEthernet1/1, changed state to down

Dec 14 14:23:15: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0950.

Dec 14 14:23:16: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0001.

Dec 14 14:23:16: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down

Dec 14 14:23:54: %UDLD-4-UDLD_PORT_DISABLED: UDLD disabled interface Gi1/1, aggressive mode failure detected

Dec 14 14:23:54: %PM-4-ERR_DISABLE: udld error detected on Gi1/1, putting Gi1/1 in err-disable state

Dec 14 14:23:55: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/1, changed state to down

Dec 14 14:23:56: %LINK-3-UPDOWN: Interface GigabitEthernet1/1, changed state to down

VLAN 950 is a vlan for Aruba Wireless Access Points. We have 3 connected to this particular switch. GigabitEthernet1/1 was the fiber uplink in question.

[miguel.desantiago]

I know this goes without saying but it seems like you have a spanning tree issue!

Try doing a show spanning-tree summary and look for the following differences on the 6509 and 3560.

EtherChannel misconfig guard            is enabled

Extended system ID                      is enabled

Portfast Default                        is disabled

Portfast Edge BPDU Guard Default        is disabled

Portfast Edge BPDU Filter Default       is disabled

Loopguard Default                       is disabled

PVST Simulation Default                 is enabled but inactive in pvst mode

Bridge Assurance                        is enabled but inactive in pvst mode

UplinkFast                              is disabled

BackboneFast                            is disabled

Pathcost method used                    is short

The underlined features should be disabled for Core and Distribution switches and only enabled on access switches that users plug into.

Hope this helps!!

[Leo Laohoo]

Loop guard????

Can you please post the output to the command "sh run int g 1/1"?

[ytanskiy]

Upon further troubleshooting, I found that the spanning tree on Aruba is set to rapid. My CISCO network is set to rapid-pvst. I will set Aruba to rapid-pvst shortly.

We switched the gbic to 1/2. Here is the output of the command.

#sh run int g 1/2
Building configuration...

Current configuration : 273 bytes
!
interface GigabitEthernet1/2
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,371,471,950,960
switchport mode trunk
srr-queue bandwidth share 1 70 25 5
srr-queue bandwidth shape 30 0 0 0
queue-set 2
priority-queue out
mls qos trust dscp
end