Abstraction and sharing an architectural view of networking

Summary form only given. It is argued that a network can be regarded as either a piece of technology or an abstraction. As an abstraction, it presents to the user a set of services that can be invoked to establish a data transfer path between endpoints. While these services are derived from the capabilities of the underlying network technology, the two can seem very decoupled. It is suggested that the key problems in design of abstraction (and technology) are delay and multiplexing, or sharing. Sharing arises for economic and fundamental reasons. An economic motivator is the high cost of some network components, most obviously the actual bandwidth and the interface modules, but more fundamental is the need to interwork with a set of units on a very dynamic basis. Computer applications seem to match well to a service model that permits several conversations to different remote sites to be interleaved in real time and to be established with little overhead or delay.<>