Optional Tasks

The following tasks are optional.

Configure the SLARP keepalive interval.host1(config-if)#hdlc keepalive 10
Enable loopback detection on an interface.host1(config-if)#hdlc down-when-looped
Disable an interface.host1(config-if)#hdlc shutdown

hdlc down-when-looped

hdlc keepalive

Use to specify the keepalive timeout value.
When the keepalive timer expires, the interface increments its own counter; then it compares the value of this counter with the last value received from a peer. If the difference between the values of the two counters is greater than three, the Cisco HDLC interface is declared down. After that, the interface sends a keepalive message containing the value of its counter and the last received value of the peer’s counter.
The router stores the values received in keepalive messages from a peer interface. If the interface is down, the router compares the received value of its own counter with the value from the peer. If the difference between the values of the two counters is less than four, the router declares the interface to be up. Both sides have to configure the same value for the keepalive interval.
If the keepalive interval is 10 seconds, then a failed link is detected between 30 and 40 seconds after failure.
The range is 0–6553 seconds. A value of 0 turns keepalive off.
The default is 10 seconds.
Examplehost1(config-if)#hdlc keepalive 10
Use the no version to turn off the keepalive feature.
See hdlc keepalive.

hdlc shutdown

Use to terminate a Cisco HDLC session.
This command administratively disables the interface.
Examplehost1(config-if)#hdlc shutdown
Use the no version to restart a disabled session. The default for each hdlc shutdown command is the no version.
See hdlc shutdown.