You can configure several L2TP drain operations, which determine how the router creates new L2TP destinations, tunnels, and sessions. You can manage the following features:
You use the l2tp drain command to prevent the creation of new destinations, tunnels, and sessions on the router.
The l2tp drain command and the l2tp shutdown command both affect the administrative state of L2TP on the router. Although each command has a different effect, the no version of each command is equivalent. Each command’s no version leaves L2TP in the enabled state.
You use the l2tp drain destination command to prevent the creation of new tunnels and sessions at a specific destination.
The l2tp drain destination command and the l2tp shutdown destination command both affect the administrative state of L2TP for the destination. Although each command has a different effect, the no version of each command is equivalent. Each command’s no version leaves L2TP in the enabled state.
- host1(config)#l2tp drain destination ip 172.31.1.98
Use the l2tp drain tunnel command to prevent the creation of new sessions for a tunnel.
The l2tp drain tunnel command and the l2tp shutdown tunnel command both affect the administrative state of L2TP for the tunnel. Although each command has a different effect, the no version of each command is equivalent. Each command’s no version leaves L2TP in the enabled state.
- host1(config)#l2tp drain tunnel virtual-router
default ip 172.31.1.98 isp.com
Use the l2tp tunnel short-drain-timeout command to specify the amount of time a disconnected LAC L2TP tunnel waits before restarting after it receives a restart request.
You can specify a drain timeout in the range 0–31 seconds. This feature enables the router to restart tunnels more quickly than the standard 31-second drain time specified by RFC-2661. By default, the router uses a short-drain timeout of 2 seconds.