Configure Keepalives

By default, physical interfaces configured with Cisco HDLC or PPP encapsulation send keepalive packets at 10-second intervals. The Frame Relay term for keepalives is Local Management Interface (LMI) packets; the JUNOS software supports both ANSI T1.617 Annex D LMIs and ITU Q933 Annex A LMIs. On ATM networks, Operation, Administration, and Maintenance (OAM) cells perform the same function. You configure OAM cells at the logical interface level; for more information, see Define the ATM OAM F5 Loopback Cell Period.

To disable the sending of keepalives on a physical interface, include the no-keepalives statement at the [edit interfaces interface-name] hierarchy level:

[edit interfaces interface-name]

no-keepalives; 

When you configure PPP over ATM or Multilink PPP over ATM encapsulation, you can enable or disable keepalives on the logical interface. For more information, see Configure PPP over ATM 2 Encapsulation.

To explicitly enable the sending of keepalives on a physical interface, include the keepalives statement at the [edit interfaces interface-name] hierarchy level:

[edit interfaces interface-name]

keepalives; 

To change one or more of the default keepalive values, include the appropriate option at the [edit interfaces interface-name] hierarchy level:

[edit interfaces interface-name]

keepalives <interval seconds> <down-count number> <up-count number>;

On interfaces configured with Cisco HDLC or PPP encapsulation, you can configure the following three keepalive statements; note that Frame Relay encapsulation is not affected by these statements:

• interval seconds—The time in seconds between successive keepalive requests. The range is 1 second through 32767 seconds, with a default of 10 seconds.
• down-count number—The number of keepalive packets a destination must fail to receive before the network takes a link down. The range is 1 through 255, with a default of 3.
• up-count number—The number of keepalive packets a destination must receive to change a link's status from down to up. The range is 1 through 255, with a default of 1.

For information about Frame Relay keepalive settings, see Configure Frame Relay Keepalives.