The IPSANET X.25 Gateway

Malcolm Prescott, European Communications Manager, London

For several years, IPSANET has maintained X.25 gateways to enable access from public networks such as Telenet, Tymnet, Datapac, PSS, Datex-P and Austpac. Now distributed software sites may also be connected to IPSANET by an X.25 link. This alternative provides comparable service to using an IBM 3705 (or equivalent) which is dedicated to connecting a site to IPSANET and running I. P. Sharp's Emulator Program (IEP).

The connection between SHARP APL and IPSANET is through VTAM and an IBM 3705 or 3725 with network control program (NCP) and network packet-switching interface (NPSI). This type of connection can provide two basic services: the support of asynchronous terminals connected to IPSANET and the Network Shared Variable Processor (NSVP).

The support for asynchronous ASCII terminals allows the connection of terminals to a distributed SHARP APL system from any access point on IPSANET. At the network level, IPSANET acts as the data circuit-terminating equipment (DCE) end of an X.25 connection from NPSI.

The IPSANET X.25 gateway to distributed SHARP APL systems has been installed at several sites. A recent installation in Birmingham, U.K., provides a second path from IPSANET to the Massey-Ferguson* European data centre. Massey-Ferguson has an existing link to IPSANET via an IBM 3705 running IEP.

Massey-Ferguson needed to provide users of their own private network a way to call out to SHARP APL systems, other than their own, without passing through mainframe software. The introduction of an IPSANET X.25 gateway and a transparent Massey-Ferguson X.25 network switch currently enables calls from terminals connected to the Massey-Ferguson mainframe, the Massey-Ferguson network or IPSANET, to call out to multiple distributed SHARP APL systems.

*Massey-Ferguson recently changed its corporate name to Varity Corporation.


X.25 PAD Now Available

As an additional service, I.P. Sharp is now a distributor for the Memotec X.25 packet assembler/disassembler (PAD). Many sites are currently using these devices in their offices to connect several asynchronous terminals and a single X.25 line to the nearest IPSANET Alpha computer. This is an alternative to using several phone lines or having an Alpha resident at the site, and may be more cost-effective.

For more information, contact your local I.P. Sharp network control centre.