HP ProCurve 6120G/XG, Configuration Manual

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Port Status and Configuration
Uni-Directional Link Detection (UDLD)
Syntax: link-keepalive interval < interval >
Determines the time interval to send UDLD control packets. The
<interval> parameter specifies how often the ports send a UDLD
packet. You can specify from 10 – 100, in 100 ms increments,
where 10 is 1 second, 11 is 1.1 seconds, and so on.
Default: 50 (5 seconds)
Syntax: link-keepalive retries < num >
Determines the maximum number of retries to send UDLD
control packets. The <num> parameter specifies the maximum
number of times the port will try the health check. You can specify
a value from 3 – 10.
Default: 5
Syntax: [no] interface < port-list > link-keepalive vlan < vid >
Assigns a VLAN ID to a UDLD-enabled port for sending of tagged
UDLD control packets.Under default settings, untagged UDLD
packets can still be transmitted and received on tagged only
ports—however, a warning message will be logged.
The
no
form of the command disables UDLD on the specified
port(s).
Default: UDLD packets are untagged; tagged only ports will
transmit and receive untagged UDLD control packets
Enabling UDLD
UDLD is enabled on a per port basis. For example, to enable UDLD on port
a1, enter:
ProCurve(config)#interface al link-keepalive
To enable the feature on a trunk group, enter the appropriate port range. For
example:
ProCurve(config)#interface al-a4 link-keepalive
When at least one port is UDLD-enabled, the switch will forward out UDLD
packets that arrive on non-UDLD-configured ports out of all other non-UDLD­
configured ports in the same vlan. That is, UDLD control packets will “pass
through” a port that is not configured for UDLD. However, UDLD packets will
be dropped on any blocked ports that are not configured for UDLD.
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