Configuring BGP to first send updates of the default route

Typically a BGP router does not first send update messages of the default route to its peers. If the peer relationship is down, the default route cannot be withdrawn first. Traffic interruption might occur. Perform this task to configure BGP to first send the update message of the default route. This can reduce the traffic interruption time when the peer relationship is down.

As shown in Figure 60, Device A and Device B send a default route and large numbers of external routes to the internal network. After optimal route selection, Device E selects Device A as the egress router to reach the external network. If the peer relationship between Device A and Device C is down, Device C sends route withdrawal messages to Device E. If the withdrawal message of the default route is not sent first, traffic forwarded through the default route will be interrupted. After you configure this task, traffic can be immediately switched to Device D to reduce traffic interruption time.