Port Status and Configuration

Uni-Directional Link Detection (UDLD)

connected ports. UDLD-enabled ports; however, will prevent traffic from being sent across a bad link by blocking the ports in the event that either the individual transmitter or receiver for that connection fails.

Ports enabled for UDLD exchange health-check packets once every five seconds (the link-keepalive interval). If a port does not receive a health-check packet from the port at the other end of the link within the keepalive interval, the port waits for four more intervals. If the port still does not receive a health- check packet after waiting for five intervals, the port concludes that the link has failed and blocks the UDLD-enabled port.

When a port is blocked by UDLD, the event is recorded in the switch log or via an SNMP trap (if configured); and other port blocking protocols, like spanning tree or meshing, will not use the bad link to load balance packets. The port will remain blocked until the link is unplugged, disabled, or fixed. The port can also be unblocked by disabling UDLD on the port.

Configuring UDLD

When configuring UDLD, keep the following considerations in mind:

UDLD is configured on a per-port basis and must be enabled at both ends of the link. See the note below for a list of ProCurve switches that support UDLD.

To configure UDLD on a trunk group, you must configure the feature on each port of the group individually. Configuring UDLD on a trunk

 

group’s primary port enables the feature on that port only.

 

Dynamic trunking is not supported. If you want to configure a trunk

 

group that contains ports on which UDLD is enabled, you must

 

remove the UDLD configuration from the ports. After you create the

 

trunk group, you can re-add the UDLD configuration.

 

 

N o t e

UDLD interoperates with the following ProCurve switches: 2600, 2800, 3400,

 

3500, 4200, 5300, 5400, 6200, 6400, 6600, 8212, and 9300. Consult the release

 

notes and current manuals for required software versions.

 

The following commands allow you to configure UDLD via the CLI.

 

Syntax: [no] interface <port-list> link-keepalive

Enables UDLD on a port or range of ports.

To disable the feature, enter the no form of the command.

Default: UDLD disabled

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