Supporting the Internet Protocols in a High Performance Real-Time Network

This licentiate thesis presents a method for using a high performance network based on circuit switching as a new link level technology for the Internet. The network is called Dynamic synchronous Transfer Mode, DTM, which provides a service based on simplex multirate channels. DTM uses resource reservation and synchronous switching, which gives good real-time support. These features make DTM well suited for applications that generate a mix of video, audio and file transfer traffic. Such applications require network services providing high capacity and timely delivery of data. The DTM protocol suite spans from the medium access control up to the network level, and the thesis shows how DTM's protocol suite can be brought together with the protocols used within the Internet, i.e., the TCP/IP suite. In addition, a programming interface is presented, which gives applications direct access to the services provided by DTM. The thesis describes a protocol architecture, which has been implemented in the form of a UNIX network device driver for a Sun SPARCstation's host/network interface. The device driver includes interfaces to IP and to the sockets programming interface. The host/network interface and the related software often constitute limiting factors for the end-to-end performance in a network with link capacities over a gigabit per second. Measurements of the I/O performance between the workstation and the host/net-work interface are reported in this thesis. Further, the thesis deals with issues such as management of DTM channels for connectionless IP traffic and new methods for address resolution. 2 3 Acknowledgements I first want to thank my advisors, Prof. Björn Pehrson and Dr. Peter Sjödin. Many thanks also to Lars Gauffin for inspiration and for his and Björn's initiative to start the research project within which this thesis work has been performed. I am especially grateful to Peter Sjödin, for his encouragement of my work and for all his valuable comments on this thesis. I am very thankful to my friends and colleagues Christer Bohm, Per Lindgren and Lars Ramfelt. We have had many stimulating discussions and good times during the years we have worked together. The opportunity to work with them was the main reason that I started my licentiate work. I also want to express my gratitude to Bengt Ahlgren at SICS (Swedish Institute of Computer Science). We developed the software architecture described in this thesis together, and it was Bengt who gave me the introductory lessons in " UNIX …