Pppoe server client session is not disconnecting even power off the client router!

In my VYOS configuration the pppoe client does not disconnect till 2 min even power off the client router. is the any option to configure as keepalive time out

Best Regards
Arun Tamrakar

Perhaps this command will help you?
set interfaces pppoe <interface> idle-timeout <time>
Use this command to set the idle timeout interval to be used with on-demand PPPoE sessions. When an on-demand connection is established, the link is brought up only when traffic is sent and is disabled when the link is idle for the interval specified.

If this parameter is not set or 0, an on-demand link will not be taken down when it is idle and after the initial establishment of the connection. It will stay up forever.

https://docs.vyos.io/en/latest/configuration/interfaces/pppoe.html#cfgcmd-set-interfaces-pppoe-interface-idle-timeout-time