Heartbeats

Client Heartbeat messages are sent from TPH to CFE and Server Heartbeat messages are sent from CFE to TPH if no other data has been sent in that direction for one second. Like other session level messages, heartbeats from CFE to the TPH do not increment the sequence number. If CFE receives no inbound data or heartbeats for five seconds, a Logout Response message will be sent and the connection will be terminated. TPHs are encouraged to have a one second heartbeat interval and to perform similar connection staleness logic.