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Cisco Bug: CSCvv17044 - UDLD aggressive mode is causing switch WS-C4510R+E to reload

Last Modified

Oct 07, 2020

Products (1)

  • Cisco Catalyst 4000 Series Switches

Known Affected Releases


Description (partial)

With the UDLD in aggressive mode on Cat4500 with Sup 7-E the switch is getting crashed.

Verifying on the device it was found that there were a crash file and a full core generated, which after decoding we had the following results:

 Found that this device crashed while processing information for UDLD, which is configured in aggressive mode.

Can see a huge number of interfaces on 4500 going err-disabled due to UDLD at the same time before the crash. Seems like the UDLD started to fail which led the interface to go in error disable mode since UDLD is configured in aggressive mode.
Jun 28 19:43:32.773 PDT: %UDLD-4-UDLD_PORT_DISABLED: UDLD disabled interface Te4/3, aggressive mode failure detected\
Jun 28 19:43:32.773 PDT: %PM-4-ERR_DISABLE: udld error detected on Te4/3, putting Te4/3 in err-disable state\

Because of the above mentioned UDLD issue, the control plane went down and I can also see the OSPF neighborships going down at the same time.
Jun 28 19:43:33.700 PDT: %OSPF-5-ADJCHG: Process 1997, Nbr on TenGigabitEthernet7/5 from FULL to DOWN, Neighbor Down: Dead timer expired\
Jun 28 19:43:33.701 PDT: %OSPF-5-ADJCHG: Process 1997, Nbr on TenGigabitEthernet7/8 from FULL to DOWN, Neighbor Down: Dead timer expired\

UDLD enabled globally/ aggressive mode.
udld aggressive\
udld message time 1\
Below configuration is for the copper port. 
interface GigabitEthernet1/3\
switchport mode trunk\
switchport nonegotiate\
logging event trunk-status\
load-interval 30\
udld port aggressive\
spanning-tree guard root\
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