Ethernet, a 10 Mbit/sec CSMA/CD network, is one of the most successful LAN technologies. Considerable confusion exists as to the actual capacity of an Ethernet, especially since some theoretical studies have examined operating regimes that are not characteristic of actual networks. Based on measurements of an actual implementation, we show that for a wide class of applications, Ethernet is capable of carrying its nominal bandwidth of useful traffic, and allocates the bandwidth fairly. We discuss how implementations can achieve this performance, describe some problems that have arisen in existing implementations, and suggest ways to avoid future problems.

Pup is the name of an internet packet format (PARC Universal Packet), a hierarchy of protocols, and a style of internetwork communication. The fundamental abstraction is an end-to-end media-in dependent internetwork datagram. Higher levels of functionality are achieved by end-to-end protocols that are strictly a matter of agreement among the communicating end processes. This report explores important design issues, sets forth principles that have guided the Pup design, discusses the present implementation in moderate detail, and summarizes experience with an operational internetwork. This work serves as the basis for a functioning internetwork system that provides service to about 1000 computers, on 25 networks of 5 different types, using 20 internetwork gateways.

WFS is a shared file server available to a large network community. WFS responds to a carefully limited repertoire of commands that client programs transmit over the network. The system does not utilize connections, but instead behaves like a remote disk and reacts to page-level requests. The design emphasizes reliance upon client programs to implement the traditional facilities (stream IO, a directory system, etc.) of a file system. The use of atomic commands and connectionless protocols nearly eliminates the need for WFS to maintain transitory state information from request to request. Various uses of the system are discussed and extensions are proposed to provide security and protection without violating the design principles.