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.
Craig Mathias, an analyst at Farpoint Group in Ashland, Mass., who has advised many cities on such installations, said it is not surprising that UC-Berkeley encountered resistance to its use of utility poles and city-owned poles "because those represent a source of potential revenue" for their owners.
The issue is sure to heat up as conventional service providers, colleges, corporate campuses and cities begin providing more wide-scale outdoor wireless mesh networks, he said.
Because it placed the access points on buildings, the university had to set up directional antennas to link them to users on the ground, Archibald noted.
Because UC-Berkeley is a test environment for the wireless mesh, Cisco donated the equipment for the network, he said, adding that the products used are valued at about US$125,000. Cisco said its 1500 APs start at $3,999.
The primary reason the school wanted an outdoor mesh is to remain competitive with other schools, Archibald said. "Students coming here today have grown up with wireless technology and just sort of expect that we'll have ubiquitous coverage in as many places as possible," he said.
The network could also become invaluable in a disaster, Archibald said. The rooftop APs have a cable supplying power, although battery backups would be needed to make them useful in an earthquake or fire, he said.