Development of a file transfer protocol and associated programs for the Bridge CS/1 system
Murali Veeramoney · The Mathematics Enthusiast · 1984
An important feature of computers connected to networks is the availability of standardized protocols for communicating across the network.The International Standard Organization proposes various protocols for different levels of communi cation and the File Transfer Protocol is one of them.With the decreasing cost of computer systems it is possible to dedicate a computer as a communications server in a network.Its sole responsibility is to provide its host with the capability of communication with any other host by hiding the details of the communication.In this project a File Transfer Protocol as specified by the International Stan dards Organization is developed on a communications server CS/1 system manufactured by Bridge Communications, Inc.The author's purpose for undertaking this project was to explore current network technology while making use of software engineering techniques.After a detailed analysis and specifications the parts of the system were identified.The system consists of a File Transfer Utility on the host (connected to the CS/1) that allows a user to request the services on the CS/1, a host to CS/1 interface on the host and a CS/1 to host interface on the CS/1 that drive the hardware between the host and the CS/1 and is responsible for a logical connection between the communicating process on the host and the CS/1, a host agent on the CS/1 which accesses the File Transfer services on behalf of the host, and finally the File Transfer service that is to be built on top of the existing Virtual Terminal Connection Service.The design of these parts is discussed, and a possible implementation outlined.2-5.Communication between Client and VT Process .. 30 2-6a.Initiator State Diagram -VT Connection ...... 32 2-6b.Responder State Diagram -VT Connection ...... 33 4-1.Host to Host connection using CS/1 ........... 47 4-2.Data flow diagram of the system ............... 49 5-1.Relationship of parts of the system ........... 57 5-2a.Initiator state diagram -Initial Host to CS/1 protocol ................... 59 5-2b.Responder state diagram -Initial Host to CS/1 protocol ....................