Optical routing to set bandwidth free

A group of start-ups soon will deliver a new class of routers aimed at building more reliable public networks that could ultimately provide customers with less costly bandwidth.

The new gear - from Monterey Networks, New Access and others - adds intelligence to dense wavelength division multiplexing (DWDM) technology, which is typically found at the core of carrier networks. The idea is to tweak DWDM nets by adding optical routers. The new boxes take in optical traffic from DWDM multiplexers and switch the individual wavelengths.

The drawback to DWDM is that it only functions point to point. So if a point fails, all calls on the path are lost until an alternative path can be set up and individual sessions are re-established.

With optical routers, DWDM traffic is switched wavelength by wavelength as it comes into optical hub sites, allowing carriers to establish meshed optical nets. The result is a more reliable net with virtually no downtime because the routers share network data and are smart enough to quickly route around failures, says Michael Guess, vice president of engineering for telecom carrier IXC Communications. It also means potentially lower prices because the bandwidth is managed more efficiently, Guess says.

Monterey Networks is working on what it calls an optical wavelength router that will switch DWDM light streams from one fiber to another (see graphic).

For example, a DWDM lightwave traveling from San Francisco to Chicago needs to be switched to New York. A Monterey wavelength router in Chicago takes a beam from San Francisco in one port, converts it to an electrical signal within the router, and reconverts it to an optical signal of the appropriate color. The router then puts the signal out on another port to New York. The box never parses the packets carried by the light.

Meanwhile, all the Monterey boxes in a network talk to each other, sharing status, bandwidth availability and other data.

While Monterey is dealing with efficiencies in the core of carrier networks, New Access is dealing with making local fiber access rings more efficient.