What everyone wants from an ISDN local area network bridge is a box that can intelligently select how many dial-up circuits it needs to cope with traffic flow. Even better, it should be able to dial up extra links or drop existing ones as congestion changes during a session. It looks as though we are getting there. Leighton Buzzard-based Acculab had been the beneficiary of patents from the British Technology Group’s ISDN bandwidth on demand system, called RAMP. Used for local network bridging, RAMP’s big selling point is that it can call up or drop ISDN lines on the fly. Moreover, the company claims that 100% of the raw bandwidth is available for users’ data – no extra header information is injected by the system – and that there is no danger of data being lost while the circuits are bobbing up and down. Each box aggregates up to 30 64Kbps ISDN B-channels into a virtual pipeline, but the company is cagey about the techniques used to determine the bandwidth required, saying that this lies at the heart of the British Technology Group patents. Potential competitors might be interested to know that Acculab does not have an exclusive agreement for the technology although, during the course of its development work, the company did file applications for two extra patents giving it what it believes is a valuable head start. What it doesn’t have, however, is a distributor for the RAMP boards which cost #1,750 for a DASS2 version, #1,950 for the DPNS version. It is actively looking for one, also for firms interested in developing applications for the AT-compatible boards.
