Ann Arbor, Michigan-based Symplex Communications Inc has now revealed more details of the Direct Route technology first hinted at a few weeks ago. The system is designed for the transmission of data across geographically-dispersed local networks, and uses multiple ISDN connections, although it can also be used over Frame Relay networks or leased lines, to aggregate bandwidth according to demand, adding or severing connections as needed. The low-end model in the family, the DR1, uses the ISDN Basic Rate Interface – with each connection operating at 512Kbps – while the DR3 and DR5 can also use 1,024Kbps ISDN Primary Rate Interface services. The DR1 is a fixed configuration, Ethernet-only, device aimed at small remote offices, which the company says can transmit to eight sites simultaneously.
Protocol-independent
The two-slot DR2 and five-slot DR5 also include Token Ring interfaces, and provide simultaneous transmission to 64 and 160 sites respectively. While all of the models are said to be protocol independent, the DR2 and DR5 are also said to include an Systems Network Architecture prioritisation feature to ensure the delivery of Systems Network Architecture traffic. These two models are available immediately costing $7,000 and $8,000 respectively, while the DR1 is to cost $3,000 and will be available towards the end of the year. All of the models are manageable via SNMP or Telnet, while the company is also introducing Direct Route NMS, a Windows-based management system said to provide network usage, call duration, bandwidth utilisation and charge-back reports. Symplex believes that the products will be most attractive to users – particularly those with variable or unpredictable bandwidth needs – who find the fixed overheads of leased lines uneconomic. While aggregating several ISDN channels obviously brings a trade-off in terms of costs, Symplex points out that it is only the monthly rental and installation charges that actually add to these, since aggregating eight ISDN channels, for example, means that the line time on each is one eighth of what it would have been if one line was used. While the company recognises that the popularity of X25 packet services in Europe may make its task harder than in the US, it feels that the bandwidth flexibility with the products bring will be enough to attract users. Similarly, the company recognises that the benefits of Direct Route are similar to those of Asynchronous Transfer Mode, but feels that Direct Route scores over Asynchronous Transfer Mode in that Asynchronous Mode services are currently thin on the ground, and that users do not necessarily yet need the very high bandwidths provided by Asynchronous Transfer technology, but are able to build up to this incrementally with Direct Route.
