● Each machine supporting TCP has a TCP transport entity, either a library procedure, auser process, or part of the kernel. In all case, it manages TCP streams and  71） to the IP layer.A TCP  （72） accepts user data streams from local process, breaks them into pieces notexceeding 64KB, and sends each piece as a separate IP （73） . When datagrams containing TCPdata arrive at a machine, they are given to the TCP entity, which reconstructs the original bytestreams.The IP layer gives no guarantee that datagrams will be delivered properly, so it is up to TCPto time out and  74） them as need be. Datagrams do arrive may well do so in the wrong order,it is also up to TCP to （75） them into messages in the proper sequence.