This read-write Integer32 (0-65535) sets the echo timeout, in seconds, that governs how long the device waits for a PPP echo-reply keepalive from the far end of an L2TP-tunneled PPP session before declaring it dead. A shorter timeout lets the switch reclaim a hung session and its resources faster, while a longer one tolerates a congested or high-latency access network without flapping the link. An engineer troubleshooting sessions that drop over a lossy DSL backhaul might raise this from the default to, say, 60 seconds to avoid premature teardown.