Skip to main content

Primary Rate ISDN OSI Office Facilities


The objective of the PROOF project is to provide interconnectivity between workstations and servers in a mixed ISDN and Ethernet LAN environment and to explore how existing applications might be affected by, and new applications could take advantage of, such interconnectivity.
The following techniques and capabilities were developed:
a gateway to connect the public primary rate ISDN (PRI) to existing Ethernet local area networks (LANs);
a very efficient inverse multiplexer capability conforming to the BONDING standard to aggregate high bandwidth across the integrated services digital network (ISDN) by combining a number of discrete 64 Kbit/s calls and compensating for unequal cross network propagation delays;
experiments with home working, using dial up workstation to LAN connection across the public ISDN. These showed that circumstances exist where, by adopting suitable automatic disconnection and reconnection strategies, near LAN performance can be achieved across the ISDN at a significant saving over medium distance commuting costs;
a flexible PRI common channel signalling protocol converter interfacing between the Euro-ISDN 1.421 protocol and others such as the UK DASS 2 standard;
a channel groomer capable of sharing a single PRI access between a number of diverse, concurrently operating, ISDN equipments;
open systems interconnection (OSI) management, management information bases (MIB) for X.400 mail and X.500 directory services;
integration of security and X.500 directory services, with remote authentication across X.25 and ISDN networks;
integration of these services within a comprehensive OSI management system.
The final demonstration would show applications running over OSI protocol stacks supported on workstations and servers directly attached both to LANs and to a digital PABX. High performance LAN interconnect would be shown with gateways operating between LANs and Primary Rate ISDN (PRI) on the PBX.

As the project evolved further objectives were added including some evaluation of true WAN usage and home working - the original ISDN PBX was replaced by use of switched Public ISDN connections, including Basic Rate (BRI) as well as PRI. New applications included multimedia and high quality video using an "inverse multiplexer" to aggregate sufficient ISDN bandwidth.


3 NET Ltd
Ringway House Bell Road Daneshill
RG24 0QG Basingstoke
United Kingdom

Participants (3)

Siemens Nixdorf Informationssysteme AG
Fürstenallee 7
33102 Paderborn
System Wizards Srl
Via Breglio 103
10147 Torino
Birkbeck College, University of London
United Kingdom
Malet Street, Bloomsbury
WC1E 7HX London