Ever wish you could change history and force the people who decided T-3 carrier networks would run at 45Mbps to talk to the people who decided Ethernet would run at 10Mbps and 100Mbps and work out something more compatible?

The people at Geyser Networks Inc. in Sunnyvale, Calif. have shared the same fantasy.

The latest start-up of broadband network legend Wu-Fu Chen says it’s pointless to ask service providers to abandon their traditional method of wrapping 45Mbps T-3 connections into self-restoring 51Mbps SONET frames just because it potentially wastes so much bandwidth as Ethernet breaks into the wide area.

Instead, Geyser has developed an optical service switch that efficiently packs enterprise networks’ LAN traffic flows into SONET metropolitan transport networks, giving service providers a chance to boost circuit utilization and potentially reduce prices.

The OSM 4800 Optical Services Manager, demonstrated recently at the National Fiber Optics Engineers Conference in Denver, uses what Geyser dubs FlexBand technology to concatenate – or lash together – relatively small chunks of SONET transport on the fly to give users the ability to send bursty traffic over a shared metro infrastructure.

That means service providers can do in ultrabroadband metro networks what they’ve done in long-haul packet networks like Frame Relay to keep prices down -“oversubscribe,” or let users share bursting ability while retaining the feel of a dedicated pipe.

By retaining such traditional features as SONET add/drop multiplexing, Geyser enables local carriers to maintain their current methods of circuit rerouting around failures and support for real-time voice and video over time-division multiplexing.

Geyser is being cagey about what the OSM 4800 will cost. Because the box supports dense wave division multiplexing for boosting optical horsepower and Multi-protocol Label Switching for integration of IP and ATM traffic, the switch is expected to be sold for carrier-edge and core networks. For smaller service providers, that could mean a price that puts it “out of their league,” according to a recent report from analyst firm Current Analysis.

Geyser officials say they’re largely going after service providers that earlier committed to expensive SONET electronics.

“Our value proposition is not to take all of that, throw it away, and start all over,” says Kent Novak, Geyser’s vice-president of marketing.

In hardware, the OSM 4800 performs a concatenation of SONET-standard 1.5Mbps “virtual tributaries,” and this so-called N-times-virtual tributaries concatenation does not need to be fixed in advance for each customer. Geyser officials claim their box checks traffic flows every millisecond to determine whether the number of virtual tributaries needs to be expanded or contracted for each customer, sending a message through the SONET overhead to the other switches on the network.

The idea is to avoid the typical low average circuit utilization in SONET – five per cent to 10 per cent in the access network and 20 per cent to 30 per cent in the core, according to Geyser. Using the OSM 4800, a 10Mbps transparent LAN service would require seven virtual tributaries connections. This way, “you don’t have to take a 10Mbps service and put it inside a 45Mbps circuit and waste 77 per cent of the traffic,” Novak says.

Users also benefit in that the virtual tributaries are provisioned dynamically. The constant reassessment of traffic flow means low jitter – or variation in delay – thus accommodating voice and video traffic between the SONET endpoints.

“Low jitter and dynamic allocation of bandwidth support a broad range of services,” says Andrew McCormack, senior analyst at Aberdeen Group Inc. in Boston.

Geyser is at