10-17-2023 12:21 AM
Hello,
I want to use UDLD in this configuration but I notice a big problem if I cut the cable between the two media converters in the center of the image :
UDLD detects the outage and shuts down the ports on switches (Te1/16). Then after 30s (recovery udld) it reactivates the port Te1/16 while the connection between the two media converters is cut...
*Oct 16 23:23:13.210: %UDLD-4-UDLD_PORT_DISABLED: UDLD disabled interface Te1/16, aggressive mode failure detected
*Oct 16 23:23:13.210: %PM-4-ERR_DISABLE: udld error detected on Te1/16, putting Te1/16 in err-disable state
*Oct 16 23:23:14.210: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/16, changed state to down
*Oct 16 23:23:15.210: %LINK-3-UPDOWN: Interface Vlan1, changed state to down
*Oct 16 23:23:15.211: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/16, changed state to down
*Oct 16 23:23:16.210: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
*Oct 16 23:23:43.207: %PM-4-ERR_RECOVER: Attempting to recover from udld err-disable state on Te1/16
*Oct 16 23:23:46.075: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/16, changed state to up
*Oct 16 23:23:47.075: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/16, changed state to up
*Oct 16 23:24:16.075: %LINK-3-UPDOWN: Interface Vlan1, changed state to up
*Oct 16 23:24:17.075: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up
Switch#sh udld neighbors
Port Device Name Device ID Port ID Neighbor State
---- ----------- --------- ------- --------------
Switch#sh spanning-tree vlan 1
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 32769
Address 286f.7f24.ef00
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 286f.7f24.ef00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 15 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Te1/16 Desg FWD 4 128.16 P2p
!
errdisable recovery cause udld
errdisable recovery interval 30
!
interface TenGigabitEthernet1/16
udld port aggressive
udld fast-hello 200
!
The problem is that traffic will fail ! Is there a function to force the port to stay DOWN when the neighbor is not reachable ?
Use loopguard on port Te1/16 to avoid having traffic on this interface ?
Thanks.
10-17-2023 12:32 AM
- Check port configuration on Te1/16 , are you using any form of auto recovery (commands) ?
M.
10-17-2023 12:37 AM
@marce1000The config of port Te1/16 is in the last post.
!
errdisable recovery cause udld
errdisable recovery interval 30
!
interface TenGigabitEthernet1/16
udld port aggressive
udld fast-hello 200
!
10-17-2023 12:50 AM
- Remove the errdisable recovery commands if you don't want automatic recovery of an udld failure ,
M.
10-17-2023 12:55 AM
I would like the port to automatically go UP but not let traffic pass if its neighbor does not respond... Possible to do this ?
10-17-2023 12:59 AM
It not easy' the admin must handle some time.
But for me the best solution is
1- remove recovery
2- config eem to no shut ther errdisable port after wait for example 10 min.
3- admin cab no shut the port manually in time between eem detect errdisable and action no shut
That only way I see.
10-17-2023 01:46 AM
Hmm I see but I still have a doubt about the solution. Imagine the cable between the two media converters is cut... I don't know what the recovery time will be.
During downtime the port must remain DOWN so as not to have traffic sent on this interface.
10-17-2023 03:07 AM
>During downtime the port must remain DOWN so as not to have traffic sent on this interface.
That's why you don't want any form of errdisable recovery commands on the port configuration,
M.
10-20-2023 04:07 AM
I think we don't understand each other.
I'm looking for a solution but it doesn't seem to exist ! If a cut occurs on the fiber or a person accidentally unplugs the fiber, UDLD detects the cut instantly and shuts the port, this part is OK.
I want the port to reactivate (no shut) and remain in Learned or Blocked mode in order to check if UDLD can reach its neighbor. Once UDLD is OK again, the port can go Forward.
10-20-2023 04:13 AM
Stp is l2
Udld is l1
The time udld detects neighbor down is so so fast that make stp not recover from blk status and hence no traffic pass.
So you ask about errdisable' make it less than time stp need to go to forward status.
Note:- Errdisable recovery is effect all port even that not down by udld but down from other protocol.
10-20-2023 04:20 AM
>...I want the port to reactivate (no shut) and remain in Learned or Blocked mode in order to check if UDLD can reach its neighbor. Once UDLD is OK again, the port can go Forward.
- That can't be done, UDLD sits at layer1 it doesn't know how 'to reach its neighbor'
M.
10-20-2023 04:22 AM
Yes I agree, that's why I said the solution doesn't seem to exist...
10-20-2023 04:31 AM
- In essence that being a good think , because it sits as layer1 or cabling issue, physical work or inspection, or using devices like fluke to analyze the fiber is more appropriate,
M.
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