Sprint Nextel’s Xohm WiMAX division will use IP backhaul technology from DragonWave in its initial batch of launch cities this fall.

“We’ve been interacting with Sprint for more than 2 years through the lab guys.  We helped them set up and define some of the architectural thinking that they did.  This is the first production network we’ve done with them,” said Alan Solheim, DragonWave vice president of product management.

Backhaul issues were the main reason for the network’s delay in Baltimore, Chicago and the District of Columbia, Sprint officials said last month.

Solheim said the non-exclusive deal involved some technological reality checks. “One of the things that Sprint found out the hard way is that a design that looks good on paper can look very different by the time you get it done,”  he said, referring to dealing with site landlords and local zoning boards.

DragonWave already worked on several other WiMAX deployments including the fixed version of Clearwire, before that company’s recent partnership with Sprint.  DragonWave engineers used such experience to help Sprint clarify its decision to favor mesh and ring architectures, which help cut costs by using smaller antennas.

The decision did not come without hiccups.  “Sprint as an entity is an interesting company to deal with.  Like any other large corporation, there are different opinions inside.  As a vendor, the customer is always right, but the customer might not know what he’s talking about,” Solheim said.

Meanwhile, DragonWave is not yet a customer of the new Clearwire, but that iteration of the company will face similar network decisions, Solheim said.  An example is the decision of how much the WiMAX network should interact with older 2G and 3G networks, he said.