Catalyst 2950 Desktop Switch Command Reference, 12.1(11)YJ
Debug Commands
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Debug Commands

Table Of Contents

Debug Commands

debug dot1x

debug etherchannel

debug lre

debug pagp

debug pm

debug spanning-tree

debug spanning-tree backbonefast

debug spanning-tree bpdu

debug spanning-tree bpdu-opt

debug spanning-tree mstp

debug spanning-tree switch

debug spanning-tree uplinkfast

debug sw-vlan

debug sw-vlan ifs

debug sw-vlan notification

debug sw-vlan vtp

debug udld


Debug Commands


This appendix describes the Catalyst 2950-specific debug privileged EXEC commands. These commands are helpful in diagnosing and resolving internetworking problems and should be used only with the guidance of Cisco technical support staff.


Caution Because debugging output is assigned high priority in the CPU process, it can render the system unusable. For this reason, use the debug commands only to troubleshoot specific problems or during troubleshooting sessions with Cisco technical support staff. It is best to use the debug commands during periods of lower network traffic and fewer users. Debugging during these periods decreases the likelihood that increased debug command processing overhead will affect system use.

debug dot1x

Use the debug dot1x privileged EXEC command to enable debugging of the 802.1X feature. Use the no form of this command to disable debugging output.

debug dot1x {all | authsm | backend | besm | core | reauthsm}

no debug dot1x {all | authsm | backend | besm | core | reauthsm}

Syntax Description

all

Enable debugging of all conditions.

authsm

Enable debugging of the authenticator state machine, which is responsible for controlling access to the network through 802.1X-enabled ports.

backend

Enable debugging of the interaction between the 802.1X process and the switch (Remote Authentication Dial-In User Service [RADIUS] client).

besm

Enable debugging of the backend state machine, which is responsible for relaying authentication request between the client and the authentication server.

core

Enable debugging of the 802.1X process, which includes 802.1X initialization, configuration, and the interaction with the port manager module.

reauthsm

Enable debugging of the re-authentication state machine, which manages periodic re-authentication of the client.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.


Usage Guidelines

The undebug dot1x command is the same as the no debug dot1x command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, refer to Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show controllers lre version

Displays 802.1X statistics, administrative status, and operational status for the switch or for the specified interface.


debug etherchannel

Use the debug etherchannel privileged EXEC command for EtherChannel/Port Aggregation Protocol (PAgP) shim debugging. This shim is the software module that is the interface between the PAgP software module and the port manager software module. Use the no form of this command to disable debugging output.

debug etherchannel [all | detail | error | event | idb | linecard]

no debug etherchannel [all | detail | error | event | idb | linecard]

Syntax Description

all

(Optional) Display all EtherChannel debug messages.

detail

(Optional) Display detailed EtherChannel debug messages.

error

(Optional) Display EtherChannel error debug messages.

event

(Optional) Debug major EtherChannel event messages.

idb

(Optional) Debug PAgP interface descriptor block messages.

linecard

(Optional) Keyword to debug Switch-Module Configuration Protocol messages to the line card.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.


Usage Guidelines

If you do not specify a keyword, all debug messages appear.

The undebug etherchannel command is the same as the no debug etherchannel command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, refer to Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show etherchannel

Displays EtherChannel information for the channel.



debug lre

Use the debug lre privileged EXEC command for debugging Long-Reach Ethernet (LRE) switches and links. Use the no form of this command to disable debugging output.

debug lre [controller | discovery | errors | profile | state | timing | upgrade] [interface-id]

no debug lre [controller | discovery | errors | profile | state | timing | upgrade] [interface-id]

Syntax Description

controller

Enables debugging of the switch.

discovery

Enables customer premises equipment (CPE) discovery debugging.

errors

Enables error debugging.

profile

Enables profile debugging.

state

Enables finite state machine (FSM) debugging.

timing

Enables timing debugging.

upgrade

Enables upgrade debugging.

interface-id

(Optional) ID of the switch port.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(11)YJ

This command was first introduced.


Usage Guidelines

This command can be entered only from the switch console.

The undebug lre command is the same as the no debug lre command.

Related Commands

Command
Description

show controllers lre status

Displays the LRE link statistics and profile information on a switch LRE port, including link state, link duration, data rates, signal-to-noise ratio, and Reed Solomon errors.


debug pagp

Use the debug pagp privileged EXEC command to debug Port Aggregation Protocol (PAgP) activity. Use the no form of this command to disable debugging output.

debug pagp [all | event | fsm | misc | packet]

no debug pagp [all | event | fsm | misc | packet]

Syntax Description

all

(Optional) Enable all PAgP debugging.

event

(Optional) Enable debugging of PAgP events.

fsm

(Optional) Enable debugging of the PAgP finite state machine.

misc

(Optional) Enable miscellaneous PAgP debugging.

packet

(Optional) Enable PAgP packet debugging.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.


Usage Guidelines

This command can be entered only from the switch console.

The undebug pagp command is the same as no debug pagp command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, refer to Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show pagp

Displays PAgP channel-group information.



debug pm

Use the debug pm privileged EXEC command to debug port manager (PM) activity. The port manager is a state machine that controls all the logical and physical interfaces. All features, such as VLANs and UniDirectional Link Detection (UDLD), work with the port manager to provide switch functions. Use the no form of this command to disable debugging output.

debug pm {all | assert | card | cookies | etherchnl | messages | port | registry | sm | span | split | vlan | vp}

no debug pm {all | assert | card | cookies | etherchnl | messages | port | registry | sm | span | split | vlan | vp}

Syntax Description

all

Display all PM debugging messages.

assert

Debug assert messages.

card

Debug line-card related events.

cookies

Enable internal PM cookie validation.

etherchnl

Debug EtherChannel-related events.

messages

Debug PM messages.

port

Debug port-related events.

registry

Debug PM registry invocations.

sm

Debug state-machine related events.

span

Debug spanning-tree related events.

split

Debug split-processor.

vlan

Debug VLAN-related events.

vp

Debug virtual-port related events.



Note Though visible in the command-line help strings, the scp and pvlan keywords are not supported.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.


Usage Guidelines

The undebug pm command is the same as the no debug pm command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, refer to Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.



debug spanning-tree

Use the debug spanning-tree privileged EXEC command to debug spanning-tree activities. Use the no form of this command to disable debugging output.

debug spanning-tree {all | backbonefast | bpdu | bpdu-opt | config | csuf | etherchannel | events | exceptions | general | mstp | pvst+ | root | snmp | switch | uplinkfast}

no debug spanning-tree {all | backbonefast | bpdu | bpdu-opt | config | csuf | etherchannel | events | exceptions | general | mstp | pvst+ | root | snmp | switch | uplinkfast}

Syntax Description

all

Display all spanning-tree debugging messages.

backbonefast

Debug Backbonefast events.

bpdu

Debug spanning-tree bridge protocol data units (BPDUs).

bpdu-opt

Debug optimized BPDU handling.

config

Debug spanning-tree configuration changes.

csuf

Debug cross-stack UplinkFast activity.

etherchannel

Debug EtherChannel support.

events

Debug spanning-tree topology events.

exceptions

Debug spanning-tree exceptions.

general

Debug general spanning-tree activity.

mstp

Debug Multiple Spanning Tree Protocol events.

pvst+

Debug Per-VLAN Spanning Tree Plus (PVST+) events.

root

Debug spanning-tree root events.

snmp

Debug spanning-tree Simple Network Management Protocol (SNMP) handling.

switch

Debug switch shim commands. This shim is the software module that is the interface between the generic Spanning Tree Protocol (STP) code and the platform-specific code of various switch platforms.

uplinkfast

Debug UplinkFast events.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.

12.1(9)EA1

The mstp and csuf keywords were added.


Usage Guidelines

The undebug spanning-tree command is the same as the no debug spanning-tree command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show spanning-tree

Displays spanning-tree state information.



debug spanning-tree backbonefast

Use the debug spanning-tree backbonefast privileged EXEC command to enable debugging of spanning-tree BackboneFast events. Use the no form of this command to disable debugging output.

debug spanning-tree backbonefast [detail | exceptions]

no debug spanning-tree backbonefast [detail | exceptions]

Syntax Description

detail

(Optional) Display detailed BackboneFast debugging messages.

exceptions

(Optional) Enable debugging of spanning-tree BackboneFast exceptions.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.


Usage Guidelines

This command can be entered only from the switch console.

The undebug spanning-tree backbonefast command is the same as the no debug spanning-tree backbonefast command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show spanning-tree

Displays spanning-tree state information.



debug spanning-tree bpdu

Use the debug spanning-tree bpdu privileged EXEC command to enable debugging of received and transmitted spanning-tree bridge protocol data units (BPDUs). Use the no form of this command to disable debugging output.

debug spanning-tree bpdu [receive | transmit]

no debug spanning-tree bpdu [receive | transmit]

Syntax Description

receive

(Optional) Enable receive BPDU debugging.

transmit

(Optional) Enable transmit BPDU debugging.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.


Usage Guidelines

This command can be entered only from the switch console.

The undebug spanning-tree bpdu command is the same as the no debug spanning-tree bpdu command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show spanning-tree

Displays spanning-tree state information.



debug spanning-tree bpdu-opt

Use the debug spanning-tree bpdu-opt privileged EXEC command to enable debugging of optimized spanning-tree bridge protocol data units (BPDUs) handling. Use the no form of this command to disable debugging output.

debug spanning-tree bpdu-opt [detail | packet]

no debug spanning-tree bpdu-opt [detail | packet]

Syntax Description

detail

(Optional) Debug detailed optimized BPDU handling.

packet

(Optional) Debug packet-level optimized BPDU handling.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.


Usage Guidelines

This command can be entered only from the switch console.

The undebug spanning-tree bpdu-opt command is the same as the no debug spanning-tree bpdu-opt command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show spanning-tree

Displays spanning-tree state information.



debug spanning-tree mstp

Use the debug spanning-tree mstp privileged EXEC command to enable debugging of the Multiple Spanning Tree Protocol (MSTP) software. Use the no form of this command to disable debugging output.

debug spanning-tree mstp {all | boundary | bpdu-rx | bpdu-tx | errors | flush | init | migration | pm | proposals | region | roles | sanity_check | sync | tc | timers}

no debug spanning-tree mstp {all | boundary | bpdu-rx | bpdu-tx | errors | flush | init | migration | pm | proposals | region | roles | sanity_check | sync | tc | timers}

Syntax Description

all

Enable all the debugging messages.

boundary

Debug flag changes at these boundaries:

An MST region and a single spanning-tree region running RSTP

An MST region and a single spanning-tree region running 802.1d

An MST region and another MST region with a different configuration

bpdu-rx

Debug the received MST bridge protocol data units (BPDUs)

bpdu-tx

Debug the transmitted MST BPDUs.

errors

Debug MSTP errors.

flush

Debug the port flushing mechanism.

init

Debug the initialization of the MSTP data structures.

migration

Debug the protocol migration state machine.

pm

Debug MSTP port manager events.

proposals

Debug handshake messages between the designated and root switch.

region

Debug the region synchronization between the switch processor (SP) and the route processor (RP).

roles

Debug MSTP roles.

sanity_check

Debug the received BPDU sanity check messages.

sync

Debug the port synchronization events.

tc

Debug topology change notification events.

timers

Debug the MSTP timers for start, stop, and expire events.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(9)EA1

This command was first introduced.


Usage Guidelines

This command can be entered only from the switch console.

The undebug spanning-tree mstp command is the same as the no debug spanning-tree mstp command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show spanning-tree

Displays spanning-tree state information.



debug spanning-tree switch

Use the debug spanning-tree switch privileged EXEC command to enable debugging of the software interface between the Spanning Tree Protocol (STP) software module and the port manager software module. Use the no form of this command to disable debugging output.

debug spanning-tree switch {all | errors | general | helper | pm | rx {decode | errors | interrupt | process} | state | tx [decode]}

no debug spanning-tree switch {all | errors | general | helper | pm | rx {decode | errors | interrupt | process} | state | tx [decode]}

Syntax Description

all

Enable all the debugging messages.

errors

Enable debugging of error messages for the interface between the spanning-tree software module and the port manager software module.

general

Enable debugging of general events.

helper

Enable debugging of the spanning-tree helper task, which handles bulk spanning-tree updates.

pm

Enable debugging of port manager events.

rx

Display received bridge protocol data unit (BPDU) handling debugging messages. The keywords have these meanings:

decode—Enable debugging of received packets.

errors—Enable debugging of receive errors.

interrupt—Enable debugging of interrupt service requests (ISRs).

process—Enable debugging of process receive BPDUs.

state—Enable debugging of spanning-tree port state changes.

tx [decode]

Display transmitted BPDU handling debugging messages.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.

12.1(9)EA1

The helper keyword was added.


Usage Guidelines

This command can be entered only from the switch console.

The undebug spanning-tree switch command is the same as the no debug spanning-tree switch command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show spanning-tree

Displays spanning-tree state information.


debug spanning-tree uplinkfast

Use the debug spanning-tree uplinkfast privileged EXEC command to enable debugging of spanning-tree UplinkFast events. Use the no form of this command to disable debugging output.

debug spanning-tree uplinkfast [exceptions]

no debug spanning-tree uplinkfast [exceptions]

Syntax Description

exceptions

(Optional) Enable debugging of spanning-tree UplinkFast exceptions.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.


Usage Guidelines

This command can be entered only from the switch console.

The undebug spanning-tree uplinkfast command is the same as the no debug spanning-tree uplinkfast command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show spanning-tree

Displays spanning-tree state information.



debug sw-vlan

Use the debug sw-vlan privileged EXEC command to debug VLAN manager activities. Use the no form of this command to disable debugging output.

debug sw-vlan {badpmcookies | cfg-vlan {bootup | cli} | events | ifs | management | notification | packets | registries | vtp}

no debug sw-vlan {badpmcookies | cfg-vlan {bootup | cli} | events | ifs | management | notification | packets | registries | vtp}

Syntax Description

badpmcookies

Display VLAN manager incidents of bad port manager cookies.

cfg-vlan bootup

Debug config-vlan messages generated when the switch is booting up.

cfg-vlan cli

Debug messages generated when the CLI is in config-vlan mode.

events

Debug VLAN manager events.

ifs

Debug VLAN manager IOS file system (IFS) error tests.

management

Debug VLAN manager management of internal VLANs.

notification

Debug VLAN manager notifications.

packets

Debug packet handling and encapsulation processes.

registries

Debug VLAN manager registries.

vtp

Debug the VLAN Trunking Protocol (VTP).


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.

12.1(9)EA1

The cfg-vlan keyword was added.


Usage Guidelines

The undebug sw-vlan command is the same as the no debug sw-vlan command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, refer to Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show vlan

Displays the parameters for all configured VLANs or one VLAN (if the VLAN name or ID is specified) in the administrative domain.

show vtp

Displays general information about VTP management domain, status, and counters.



debug sw-vlan ifs

Use the debug sw-vlan ifs privileged EXEC command to enable VLAN manager IOS file system (IFS) error tests. Use the no form of this command to disable debugging output.

debug sw-vlan ifs {open {read | write} | read {1 | 2 | 3 | 4} | write}

no debug sw-vlan ifs {open {read | write} | read {1 | 2 | 3 | 4} | write}

Syntax Description

open

Enable VLAN manager IFS debugging of errors in an IFS file open operation.

read

Enable debugging of errors that occurred when opening the IFS VLAN configuration file in order to read it.

write

Enable debugging of errors that occurred when opening the IFS VLAN configuration file in order to write to it.

read

Enable debugging of errors that occurred when performing an IFS file read operation.

{1 | 2 | 3 | 4}

Specify the file read operation.

write

Enable debugging of errors that occurred when performing an IFS file write operation.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.


Usage Guidelines

When determining the file read operation, Operation 1 reads the file header, which contains the header verification word and the file version number. Operation 2 reads the main body of the file, which contains most of the domain and VLAN information. Operation 3 reads type length version (TLV) descriptor structures. Operation 4 reads TLV data.

The undebug sw-vlan ifs command is the same as the no debug sw-vlan ifs command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, refer to Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show vlan

Displays the parameters for all configured VLANs or one VLAN (if the VLAN name or ID is specified) in the administrative domain.



debug sw-vlan notification

Use the debug sw-vlan notification privileged EXEC command to enable debugging messages that trace the activation and deactivation of Inter-Link Switch (ISL) VLAN IDs. Use the no form of this command to disable debugging output.

debug sw-vlan notification {accfwdchange | allowedvlancfgchange | fwdchange | linkchange | modechange | pruningcfgchange | statechange}

no debug sw-vlan notification {accfwdchange | allowedvlancfgchange | fwdchange | linkchange | modechange | pruningcfgchange | statechange}

Syntax Description

accfwdchange

Enable VLAN manager notification of aggregated access interface Spanning Tree Protocol (STP) forward changes.

allowedvlancfgchange

Enable VLAN manager notification of changes to the allowed VLAN configuration.

fwdchange

Enable VLAN manager notification of STP forwarding changes.

linkchange

Enable VLAN manager notification of interface link-state changes.

modechange

Enable VLAN manager notification of interface mode changes.

pruningcfgchange

Enable VLAN manager notification of changes to the pruning configuration.

statechange

Enable VLAN manager notification of interface state changes.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.


Usage Guidelines

The undebug sw-vlan notification command is the same as the no debug sw-vlan notification command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, refer to Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show vlan

Displays the parameters for all configured VLANs or one VLAN (if the VLAN name or ID is specified) in the administrative domain.



debug sw-vlan vtp

Use the debug sw-vlan vtp privileged EXEC command to enable debugging messages to be generated by the VLAN Trunking Protocol (VTP) code. Use the no form of this command to disable debugging output.

debug sw-vlan vtp {events | packets | pruning [packets | xmit] | xmit}

no debug sw-vlan vtp {events | packets | pruning [packets | xmit] | xmit}

Syntax Description

events

Display general-purpose logic flow and detailed VTP debugging messages generated by the VTP_LOG_RUNTIME macro in the VTP code.

packets

Display the contents of all incoming VTP packets that have been passed into the VTP code from the IOS VTP platform-dependent layer, except for pruning packets.

pruning

Enable debugging message to be generated by the pruning segment of the VTP code.

packets

(Optional) Display the contents of all incoming VTP pruning packets that have been passed into the VTP code from the IOS VTP platform-dependent layer.

xmit

(Optional) Display the contents of all outgoing VTP packets that the VTP code requests the IOS VTP platform-dependent layer to send.

xmit

Display the contents of all outgoing VTP packets that the VTP code requests the IOS VTP platform-dependent layer to send, except for pruning packets.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.


Usage Guidelines

If no further parameters are entered after the pruning keyword, VTP pruning debugging messages appear. They are generated by the VTP_PRUNING_LOG_NOTICE, VTP_PRUNING_LOG_INFO, VTP_PRUNING_LOG_DEBUG, VTP_PRUNING_LOG_ALERT, and VTP_PRUNING_LOG_WARNING macros in the VTP pruning code.

The undebug sw-vlan vtp command is the same as the no debug sw-vlan vtp command.

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, refer to Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show vtp

Displays general information about VTP management domain, status, and counters.



debug udld

Use the debug udld privileged EXEC command to display the UniDirectional Link Detection (UDLD) debug messages. Use the no form of this command to disable UDLD debugging.

debug udld {events | packets | registries}

no debug udld {events | packets | registries}

Syntax Description

events

Enable debugging messages for UDLD process events as they occur.

packets

Enable debugging messages for the UDLD process as it receives packets from the packet queue and tries to transmit them at the request of the UDLD protocol code.

registries

Enable debugging messages for the UDLD process as it processes registry calls from the UDLD process-dependent module and other feature modules.


Defaults

Debugging is disabled.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)EA2

This command was first introduced.


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:

Sub-block creation

Fiber-port status changes

State change indications from the port manager software

MAC address registry calls

Related Commands

Command
Description

show debugging

Displays information about the types of debugging that are enabled. For syntax information, refer to Cisco IOS Configuration Fundamentals Command Reference For IOS Release 12.1 > Cisco IOS System Management Commands > Troubleshooting Commands.

show udld

Displays UDLD administrative and operational status for all ports or the specified port.