Packet switching has been proposed as an effective technology for integrating voice and data in a single network. An important aspect of packet-switched voice is the reconstruction of a continuous stream of speech from the set of packets that arrive at the destination terminal, each of which may encounter a different amount of buffering delay in the packet network. The magnitude of the variation in delay may range from a few milliseconds in a local area network to hundreds of milliseconds in a long-haul packet voice and data network. This paper discusses several aspects of the packet voice synchronization problem, and techniques that can be used to address it. These techniques estimate in some way the delay encountered by each packet and use the delay estimate to determine how speech is reconstructed. The delay estimates produced by these techniques can be used in managing the flow of information in the packet network to improve overall performance. Interactions of packet voice synchronization techniques with other network design issues are also discussed.

The coordination of atomic updates to distributed data is a difficult problem in the design of a distributed information system. A common goal for solutions to this problem is that the failure of a site should not prevent any processing that does not require the data stored at that site. While this goal has been shown to be impossible to achieve all of the time, several approaches have been developed that perform atomic updates such that most site failures do not affect processing at other sites. This paper presents another such approach, one that provides a mechanism by which processing can proceed even if a failure occurs during a critical moment in an atomic update.

There are many good arguments for implementing information systems as distributed systems. These arguments depend on the extent to which interactions between machines in the distributed implementation can be minimized. Sharing among users of a computer utility is a type of interaction that may be difficult to provide in a distributed system.