Department of Computer Science and Technology

Technical reports

Intelligent network interfaces

Nicholas Henry Garnett

May 1985, 140 pages

This technical report is based on a dissertation submitted May 1983 by the author for the degree of Doctor of Philosophy to the University of Cambridge, Trinity College.

DOI: 10.48456/tr-46


Local Area Networks are now an accepted part of computing research. The technology of the network itself and the hardware to interface it to a computer is standard and in the cases of networks like Ethernet and the Cambridge Ring is commercially available. The next level up from the hardware is the software interface between the host computer and the network. This dissertation is concerned with one specific type of interface where the host is not itself directly connected to the network, but must access it via a second Network Interface Processor (NIP).

The dissertation begins by describing the design and implementation of the two low level interfaces for the Cambridge Ring. The first of these, the type 2, is machine independent and although based on a simple processor offers some sophisticated facilities to its host. The second, Spectrum, is not so sophisticated, but is customized to interface to just one operating system. The difference between these two approaches is discussed.

We go on to introduce the High Level Interface, which removes all protocol and network related processing from the host machine. This can benefit both the protocol implementation, by reducing system overheads, and the host operating system, by freeing CPU time for other tasks. This is particularly true in the case of time-shared machines which rely on the network for terminal connections. The design and implementation of such an interface are described.

The dissertation concludes by considering the possible roles of the NIP in the areas of security, protection and reliability. Some thoughts are also given on the design of protocols which exploit the features of a NIP.

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BibTeX record

  author =	 {Garnett, Nicholas Henry},
  title = 	 {{Intelligent network interfaces}},
  year = 	 1985,
  month = 	 may,
  url = 	 {},
  institution =  {University of Cambridge, Computer Laboratory},
  doi = 	 {10.48456/tr-46},
  number = 	 {UCAM-CL-TR-46}