This read-write Unsigned32, in seconds, specifies the timeout value for vPC peer-keepalive hello messages, presumably governing how long the device waits for a response before considering the exchange failed. Administrators tune this in conjunction with the keepalive interval to control how quickly a lost peer connection is recognized without causing false positives from transient delays. For example, setting this timeout too aggressively on a management network with occasional latency spikes could cause the vPC domain to falsely declare the peer unreachable.