History
NCP provided connections and flow control between processes running on different ARPANET host computers. Application services, such as email and file transfer, were built on top of NCP, using it to handle connections to other host computers.
On the ARPANET, the protocols in the Physical Layer, the Data Link Layer, and the Network Layer used within the network were implemented on separate Interface Message Processors (IMPs). The host usually connected to an IMP using another kind of interface, with different physical, data link and network layer specifications. The IMP's capabilities were specified by the Host/IMP Protocol in BBN Report 1822.
Since lower protocol layers were provided by the IMP-host interface, NCP essentially provided a Transport Layer consisting of the ARPANET Host-to-Host Protocol (AHHP) and the Initial Connection Protocol (ICP). AHHP defined procedures to transmit a unidirectional, flow-controlled data stream between two hosts. The ICP defined the procedure for establishing a bidirectional pair of such streams between a pair of host processes. Application protocols (e.g., FTP) accessed network services through an interface to the top layer of the NCP, a forerunner to the Berkeley sockets interface.
Read more about this topic: Network Control Program
Famous quotes containing the word history:
“It would be naive to think that peace and justice can be achieved easily. No set of rules or study of history will automatically resolve the problems.... However, with faith and perseverance,... complex problems in the past have been resolved in our search for justice and peace. They can be resolved in the future, provided, of course, that we can think of five new ways to measure the height of a tall building by using a barometer.”
—Jimmy Carter (James Earl Carter, Jr.)
“In history as in human life, regret does not bring back a lost moment and a thousand years will not recover something lost in a single hour.”
—Stefan Zweig (18811942)
“As History stands, it is a sort of Chinese Play, without end and without lesson.”
—Henry Brooks Adams (1838–1918)