Dead Peer Detection (DPD) is a method of detecting a dead Internet Key Exchange (IKE) peer. The method uses IPSec traffic patterns to minimize the number of messages required to confirm the availability of a peer. DPD is used to reclaim the lost resources in case a peer is found dead and it is also used to perform IKE peer failover.
Vigor routers supporting DPD are:
2110; 2700; 2710; 2800; 2820; 2910; 2930 and 2950 series
The DPD function is enabled in Vigor routers by default. There is no option to enable or disable it.
For other router models that do no support DPD you can use the “Ping to keep alive” option in the VPN settings instead.