Administration of the Avaya G350 Media Gateway - Avaya Support

Extended keepaliveBackup commandsUse the following commands to configure a backup interface:●●Use the backup interface command, followed by the interface type and number, to seta backup interface. You must use this command from the context of the interface for whichyou are setting a backup interface.Use the backup delay command to set the time to wait before switching over to thebackup interface, in case of failure. You can also use this command to set a delay beforereverting back to the primary interface. For example, the following command causes theG350 to switch immediately to the backup interface in the event of primary interfacefailure, and to delay 60 seconds before reverting back to the primary interface once theprimary interface is restored to service:G350-001(super-if:FastEthernet 10/2)# backup delay 0 60Extended keepaliveThe extended keepalive feature is available for WAN Fast Ethernet interfaces. Extendedkeepalive is a mechanism for determining if a certain IP address is reachable. The sourceinterface sends test packets (ping) and waits for a response. If no response is received after acertain number of tries, the connection is declared to be down.This feature provides a quick means to determine whether the interface is up or down. This isespecially important for policy-based routing, in which it is important to determine as quickly aspossible whether the next hop is available. See Configuring policy-based routing on page 273.Normal keepalive is sufficient for testing the status of a direct connection between two points.However, in many situations the system needs to know the status of an entire path in order toensure that packets can safely traverse it.Extended Keepalive is a mechanism that reports on the status of an IP address and its nexthop. The destination interface is only declared to be alive if the next hop is also reachable. Thisfeature is critical for mechanisms such as policy-based routing that must guarantee service on aparticular path.Issue 3 January 2005 99