Êtes-vous un étudiant de l'EPFL à la recherche d'un projet de semestre?
Travaillez avec nous sur des projets en science des données et en visualisation, et déployez votre projet sous forme d'application sur Graph Search.
Concept
Digital Private Network Signalling System
Résumé
The Digital Private Network Signalling System (DPNSS) is a network protocol used on digital trunk lines for connecting to PABX. It supports a defined set of inter-networking facilities.
DPNSS was originally defined by British Telecom. The specification for the protocol is defined in BTNR188. The specification currently comes under the Network Interoperability Consultative Committee.
DPNSS was developed in the early 1980s by BT, or its forerunner, Post Office Telecommunications in recognition that the emerging Digital Private Circuit Primary Rate product 'Megastream' had to address the market for both data and voice, the latter being significantly greater because of the market for PBXs. At the time, BT dictated what signalling could be used on its leased lines and, whilst it only had a minority interest in the sales of PBXs, was requested by the PBX manufacturers to produce a standard to prevent the creation of a plethora of conflicting PBX protocols being developed. Under the liberalization rules of the day (1979), BT was barred from manufacturing, selling or supplying PBXs of more than 200 extensions. Digital (PCM-based) PBXs were just starting to come into the marketplace with the Plessey PDX (a licensed version of the ROLM CBX) and the GEC SL1 (a licensed version of the Northern Telecom SL1). It was recognised that corporate customers would wish to network these systems across the country. At the time, 'CAS' inter node signaling was slow and inter-register signaling MF5, developed from PSTN signalling protocols, was complex and would not support sufficient features.
The support for DPNSS as BT's own signalling protocol also differentiated BT's private circuit's services from those of its emerging rival Mercury Communications.
DPNSS was an active (and successful) collaboration between PBX manufacturers and BT which started relatively slowly (BT & Plessey) but quickly snowballed with MITEL, GEC, Ericsson, Philips and eventually Nortel all joining to create a powerful and feature rich protocol.
À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.