Hardware manual

keepalive
Interface Commands IR-125
keepalive
To set the keepalive timer for a specific interface, use the keepalive interface configuration
command. To turn off keepalives entirely, use the no form of this command.
keepalive [seconds]
no keepalive [seconds]
Syntax Description
Default
10 seconds
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
You can configure the keepalive interval, which is the frequency at which the Cisco IOS software
sends messages to itself (Ethernet and Token Ring) or to the other end (serial), to ensure a network
interface is alive. The interval in previous software versions was 10 seconds; it is now adjustable in
1-second increments down to 1 second. An interface is declared down after three update intervals
have passed without receiving a keepalive packet.
Setting the keepalive timer to a low value is very useful for rapidly detecting Ethernet interface
failures (transceiver cable disconnecting, cable unterminated, and so on).
A typical serial line failure involves losing Carrier Detect (CD) signal. Because this sort of failure is
typically noticed within a few milliseconds, adjusting the keepalive timer for quicker routing
recovery is generally not useful.
Note When adjusting the keepalive timer for a very low bandwidth serial interface, large datagrams
can delay the smaller keepalive packets long enough to cause the line protocol to go down. You may
need to experiment to determine the best value.
Example
The following example sets the keepalive interval to 3 seconds:
interface ethernet 0
keepalive 3
seconds (Optional) Unsigned integer value greater than 0. The
default is 10 seconds.