Case Study: Using ATM WAN to connect local hospitals using 3Com PathBuilder S600 WAN access switches

The Hammersmith Hospitals NHS Trust has successfully implanted an ATM Wide Area Network, connecting two local hospitals using...

The Hammersmith Hospitals NHS Trust has successfully implanted an ATM Wide Area Network, connecting two local hospitals using 3Com PathBuilder S600 WAN access switches

The Hammersmith Hospitals NHS Trust was formed to manage four hospitals in West London. Of these, Charring Cross Hospital and Hammersmith Hospital are major teaching hospitals and nationally recognised centres of excellence in a number of specialities. As well as being an acknowledged international centre for research, the Trust cares for huge numbers of patients. In 1997 and 1998, 63,554 people attended the Accident and Emergency departments for treatment and a total of 284,338 outpatient appointments were kept.

Back in 1994, Charring Cross Hospital already had an FDDI backbone while Hammersmith Hospital had a very basic Ethernet LAN. A pair of 2Mbit/s leased lines connected the two sites.

The new Trust set about rationalising its organisation. A great deal of duplication naturally existed between the two hospitals. Concentrating particular resources on either one site or the other eliminated much of this. As a result, the need for colleagues to consult between the sites grew and data flow between the 1,800 users increased substantially. By 1996, the 4Mbit/s bandwidth provided by the links was becoming saturated with new traffic.

Mathew Williamson, head of networking and technical support for the Trust, and his colleagues began to investigate the options available and set about evaluating 8Mbit/s and 34Mbit/s alternatives. During the investigation, it transpired that Cable and Wireless could provide and manage a point-to-point fibre link cost effectively, and that 155Mbit/s ATM OC3 was a viable option. Indeed, by removing the 2Mbit/s leased lines that were carrying voice between the two sites' GPT ISDX digital private switchboards, such a solution would actually be slightly cheaper in revenue terms than upgrading to a 34Mbit/s data-only link.

Key components of the ATM solution are 3Com PathBuilder S600 WAN access switches. These are located at either end of the fibre link, and delivered converged voice and data applications. They could also support various video applications and the Trust is currently exploring the use of videoconferencing.

Today, the Trust is scoping a new project with 3Com for a second ATM OC3 link. This may well use microwave technology with doubled-up switches to provide the additional fault tolerance and resilience that is so essential in an acute hospital environment.

The Trust has NetWare 4, Windows NT and Unix platforms providing a host of office automation and hospital information systems. These range from outpatient management and pharmacy stock control to patient databases and bed allocation systems. Clinical applications include pathology management (whereby laboratory analysers feed results directly into the pathology results system), a cancer treatment database and tele-radiology.

Hammersmith Hospital is a national centre for radiology and practises in a filmless environment. In other words, X-rays are no longer displayed over lightboxes but now are accessed using high-resolution 21in monitors on Macintosh computers. This avoids the risk of losing films and allows rapid and simple access from multiple locations. Hammersmith is one of the first and largest Picture Archive and Communication Systems (PACS) in the UK. Specialists at Charring Cross regularly consult with colleagues at Hammersmith Hospital over images shared across the network.

These sorts of applications are driving yet further enhancements to the Trust's network. Until now, all workstations were linked by traditional 10Mbit/s Ethernet hubs, each of which served between 40 and 60 users and were connected by 10Mbit/s uplinks to the core. The Trust is now planning to migrate to 10/100 switching for key users and later to Gigabit Ethernet for the most bandwidth-hungry workstations.

Compiled by Will Garside

(c) 3Com Corporation 1999

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