Port Status and Configuration

Uni-Directional Link Detection (UDLD)

Changing the Keepalive Interval

By default, ports enabled for UDLD send a link health-check packet once every 5 seconds. You can change the interval to a value from 10 – 100 deciseconds, where 10 is 1 second, 11 is 1.1 seconds, and so on. For example, to change the packet interval to seven seconds, enter the following command at the global configuration level:

ProCurve(config)# link-keepalive interval 70

Changing the Keepalive Retries

By default, a port waits five seconds to receive a health-check reply packet from the port at the other end of the link. If the port does not receive a reply, the port tries four more times by sending up to four more health-check packets. If the port still does not receive a reply after the maximum number of retries, the port goes down.

You can change the maximum number of keepalive attempts to a value from 3 – 10. For example, to change the maximum number of attempts to 4, enter the following command at the global configuration level:

ProCurve(config)# link-keepalive retries 4

 

Configuring UDLD for Tagged Ports

 

The default implementation of UDLD sends the UDLD control packets

 

untagged, even across tagged ports. If an untagged UDLD packet is received

 

by a non-ProCurve switch, that switch may reject the packet. To avoid such

 

an occurrence, you can configure ports to send out UDLD control packets that

 

are tagged with a specified VLAN.

 

To enable ports to receive and send UDLD control packets tagged with a

 

specific VLAN ID, enter a command such as the following at the interface

 

configuration level:

 

ProCurve(config)#interface l link-keepalive vlan 22

 

 

N o t e s

■ You must configure the same VLANs that will be used for UDLD on

 

all devices across the network; otherwise, the UDLD link cannot be

 

maintained.

 

■ If a VLAN ID is not specified, then UDLD control packets are sent out

 

of the port as untagged packets.

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