Network administrators this spring began using the outdoor network with several brands of WiFi voice-enabled devices, including smart phones, and have found some "work good and others not so good," said Fred Archibald, a network manager at the school.

The testers have encountered some network jamming and some packet loss, Archibald said. "Our next step is to turn on Quality of Service software within the next two months," he said. Archibald wouldn't disclose the software vendor.

Archibald said the pilot wireless network, which covers about one-fifth of the Berkeley campus, "in many locations works very, very well and people are excited to use it." However, he said, "user expectations with wireless are very, very high and people expect it to work as well as the wired network. It often doesn't, so they can be disappointed."

For the outdoor network, UC-Berkeley installed 12 Cisco Aironet 1500 Series access points on rooftops of school buildings ranging from two to nine stories tall. That decision followed resistance from utility companies and city officials over the school's desire to use power and light poles to locate the access points closer to the ground, Archibald said.

In general, outdoor wireless mesh networking "is more challenging than indoor wireless networks," Archibald said -- partly because it can be hard to find the right places to mount access points to provide proper coverage.