Cisco Catalyst 3550

B-53
Catalyst 3550 Multilayer Switch Command Reference
OL-8566-02
Appendix B Catalyst 3550 Switch Debug Commands
debug udld
debug udld
Use the debug udld privileged EXEC command to enable debugging of the UniDirectional Link
Detection (UDLD) feature. Use the no form of this command to disable debugging.
debug udld {events | packets | registries}
no debug udld {events | packets | registries}
Syntax Description
Defaults Debugging is disabled.
Command Modes Privileged EXEC
Command History
Usage Guidelines For debug udld events, these debugging messages appear:
• General UDLD program logic flow
• State machine state changes
• Program actions for the set and clear ErrDisable state
• Neighbor cache additions and deletions
• Processing of configuration commands
• Processing of link-up and link-down indications
For debug udld packets, these debugging messages appear:
• General packet processing program flow on receipt of an incoming packet
• Indications of the contents of the various pieces of packets received (such as type length versions
[TLVs]) as they are examined by the packet reception code
• Packet transmission attempts and the outcome
For debug udld registries, these categories of debugging messages appear:
• Subblock creation
• Fiber-optic port status changes
events Display debugging messages for UDLD process events as they occur.
packets Display debugging messages for the UDLD process as it receives packets
from the packet queue and tries to send them at the request of the UDLD
protocol code.
registries Display debugging messages for the UDLD process as it processes registry
calls from the UDLD process-dependent module and other feature modules.
Release Modification
12.1(4)EA1 This command was introduced.