Specifications

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Catalyst 2950 and Catalyst 2955 Switch Command Reference
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Chapter 2 Cisco IOS Commands
show udld
show udld
Use the show udld user EXEC command to display UniDirectional Link Detection (UDLD) status for
all ports or the specified port.
show udld [interface-id] [ | {begin | exclude | include} expression]
Syntax Description
Command Modes User EXEC
Command History
Usage Guidelines If you do not enter an interface-id, the administrative and the operational UDLD status for all interfaces
appear.
Expressions are case sensitive. For example, if you enter | exclude output, the lines that contain output
do not appear, but the lines that contain Output appear.
Examples This is an example of output from the show udld gigabitethernet0/1 command. In this example, UDLD
is enabled on both ends of the link, and UDLD detects that the link is bidirectional. Table 2-17 describes
the fields in this example.
Switch> show udld gigabitethernet0/1
Interface gi0/1
---
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: 60
Time out interval: 5
Entry 1
Expiration time: 146
Device ID: 1
Current neighbor state: Bidirectional
Device name: 0050e2826000
Port ID: Gi0/2
interface-id (Optional) ID of the interface and port number. Valid interfaces include
physical ports and VLANs. The VLAN range is 1 to 4094 when the
enhanced software image (EI) is installed and 1 to 1001 when the standard
software image (SI) is installed. Do not enter leading zeros.
| begin (Optional) Display begins with the line that matches the specified
expression.
| exclude (Optional) Display excludes lines that match the specified expression.
| include (Optional) Display includes lines that match the specified expression.
expression Expression in the output to use as a reference point.
Release Modification
12.0(5.2)WC(1) This command was first introduced.