RFC 793:TRANSMISSION CONTROL PROTOCOL
RFC-Ref

Reliability


Click on the red underlined text to get to the source

... distinct but interconnected computer communication networks. Very few assumptions are made as to the reliability of the communication protocols below the TCP layer ...
... Basic Data Transfer Reliability Flow Control ...
... Reliability: ...
... The reliability and flow control mechanisms described above require that TCPs initialize and maintain certain status information for ...


... Type of Service = Precedence: routine, Delay: normal, Throughput: normal, Reliability: normal; or 00000000. Time to Live ...



Google
Web
RFC-Ref