The Initial Internetting Concepts, continued

• Communication between two processes would logically consist of a very long stream of bytes (they called them octets). The position of any octet in the stream would be used to identify it.

• Flow control would be done by using sliding windows and acknowledgments. The destination could select when to acknowledge and each acknowledgment returned would be cumulative for all packets received to that point.

• It was left open as to exactly how the source and destination would agree on the parameters of the windowing to be used. Defaults were used initially.

• Although Ethernet was under development at Xerox PARC at that time, the proliferation of LANs were not envisioned at the time, much less PCs and workstations. The original model was national level networks like ARPANET of which only a relatively small number were expected to exist. Thus a 32 bit IP address was used of which the first 8 bits signified the network and the remaining 24 bits designated the host on that network.

  This assumption, that 256 networks would be sufficient for the foreseeable future, was clearly in need of reconsideration when LANs began to appear in the late 1970s.