UDLD err-disabled on known good fiber

[chasem_94]

Hello all, we're running into an issue where a known good fiber path is getting disabled due to udld when we try to move ports around. We know it's good as there is a functional trunk using the underground fiber path between the two sites. We're just trying to move the ports around so they're consistent (Te5/10 to Te5/10 for example) using the fiber that trunk is currently using. The moment we move the ports around the link goes up for a few seconds then goes down due to udld. What could be causing this as the fiber path we are using is currently working as intended?

[Reza Sharifi]

Hi,

Is the configs the same for both ports?

HTH

[chasem_94]

Yes, they are identical.

[lucasfreitas83]

Hello chasem_94,

You can modify UDLD parameter of aggressive mode to normal mode.

Verify how UDLD is enabled with command bellow.

show udld port

This a palliative solution, please share logs that contains errors of this problem and port configuration of both sides.

Please rate and mark posts accordingly if you have found any of the information provided useful.
It will hopefully assist others with similar issues in the future.

Best regards,
Lucas Freitas

[chasem_94]

Our standard is set to normal mode. This is the udld info on the port that is currently working (the non functional port is disconnected)

Port enable administrative configuration setting: Follows device default
Port enable operational state: Enabled
Current bidirectional state: Bidirectional
Current operational state: Advertisement - Single neighbor detected
Message interval: 15
Time out interval: 5

Entry 1
---
Expiration time: 34
Cache Device index: 1
Current neighbor state: Bidirectional
Device ID: F44E577F80
Port ID: Te5/14
Neighbor echo 1 device: F44E578040
Neighbor echo 1 port: Te3/8

Message interval: 15
Time out interval: 5

This is the port configuration that would be set on both sides. 
switchport
switchport trunk native vlan 999
switchport mode trunk
switchport trunk allowed vlan 101,137,148,149,169,200,299,333,339,401,437,448
switchport trunk allowed vlan add 449,469,500,599,633,639,701,737,748,749,769
switchport trunk allowed vlan add 800,899,933,939,2210
switchport nonegotiate
platform qos queue-mode mode-dscp
wrr-queue bandwidth 1 25 4 10 10 10 10
wrr-queue queue-limit 10 25 10 10 10 10 10
wrr-queue random-detect min-threshold 3 70 80 90 100
wrr-queue random-detect min-threshold 4 70 80 90 100
wrr-queue random-detect min-threshold 5 70 80 90 100
wrr-queue random-detect min-threshold 6 70 80 90 100
wrr-queue random-detect min-threshold 7 60 70 80 90
wrr-queue random-detect max-threshold 1 100 100 100 100
wrr-queue random-detect max-threshold 2 100 100 100 100
wrr-queue random-detect max-threshold 3 80 90 100 100
wrr-queue random-detect max-threshold 4 80 90 100 100
wrr-queue random-detect max-threshold 5 80 90 100 100
wrr-queue random-detect max-threshold 6 80 90 100 100
wrr-queue random-detect max-threshold 7 70 80 90 100
wrr-queue random-detect 4
wrr-queue random-detect 5
wrr-queue random-detect 6
wrr-queue random-detect 7
wrr-queue dscp-map 1 1 1 2 3 4 5 6 7 8
wrr-queue dscp-map 1 1 9 11 13 15 17 19 21 23
wrr-queue dscp-map 1 1 25 27 29 31 33 39 41 42
wrr-queue dscp-map 1 1 43 44 45 47
wrr-queue dscp-map 2 1 0
wrr-queue dscp-map 3 1 14
wrr-queue dscp-map 3 2 12
wrr-queue dscp-map 3 3 10
wrr-queue dscp-map 4 1 22
wrr-queue dscp-map 4 2 20
wrr-queue dscp-map 4 3 18
wrr-queue dscp-map 5 1 30 35 37
wrr-queue dscp-map 5 2 28
wrr-queue dscp-map 5 3 26
wrr-queue dscp-map 6 1 38 49 50 51 52 53 54 55
wrr-queue dscp-map 6 1 57 58 59 60 61 62 63
wrr-queue dscp-map 6 2 36
wrr-queue dscp-map 6 3 34
wrr-queue dscp-map 7 1 16
wrr-queue dscp-map 7 2 24
wrr-queue dscp-map 7 3 48
wrr-queue dscp-map 7 4 56
priority-queue dscp-map 1 32 40 46
rcv-queue dscp-map 2 1 14
rcv-queue dscp-map 5 1 34 35 36 37 38
no cdp enable

The only logs that are generated during this event are as follows:

Jan 14 11:06:50.058: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet5/10, changed state to up

Jan 14 11:06:55.006: %UDLD-4-UDLD_PORT_DISABLED: UDLD disabled interface Te5/10, unidirectional link detected

Jan 14 11:06:55.006: %PM-4-ERR_DISABLE: udld error detected on Te5/10, putting Te5/10 in err-disable state

Jan 14 11:06:55.022: %LINK-3-UPDOWN: Interface TenGigabitEthernet5/10, changed state to down

Jan 14 11:06:55.158: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet5/10, changed state to down

Jan 14 11:06:55.162: %PM-STBY-4-ERR_DISABLE: udld error detected on Te5/10, putting Te5/10 in err-disable state

[chrihussey]

This may be overly simplistic, but if you aren't re-using the existing ones, have you tried replacing SFPs and the fiber jumpers? 

Regards

[chasem_94]

I had thought that might have been the case so we actually used a 3560-CX fresh out of the box and used brand new SFP and fiber jumpers and connected it to try and rule out that possibility. Still did the same thing.