DATAPAC: A Canadian packet switching network

Datapac is a nation-wide public packet-switched data communications network operated by the Trans-Canada Telephone System. All communications over Datapac require the establishment of a virtual circuit between subscriber terminals. In order to accommodate applications where throughput is critical without penalizing applications where response-time is critical, the most appropriate of two delivery priorities may be specified for each virtual circuit. Datapac initially supports simple asynchronous interactive terminals as well as packet-mode terminals. The packet-mode interface conforms to the international standard CCITT Recommendation X.25. This paper presents an overview of Datapac including network structure, subscriber services, switching equipment, network performance, and network control.