Hajjis, as the pilgrims are called, come to the city in Saudi Arabia from around the world for several days of religious rituals. More than 2 million gather each year. A network of about 70 meshed routers from Tropos Networks has been set up to provide free Internet connectivity, according to Denise Barton, director of marketing at Tropos. Users only have to register before using it. Barton believes it is the first public Wi-Fi network set up for the Hajj.

Mesh networks are well-suited to temporary deployments because they need fewer fixed-line connections than do traditional Wi-Fi systems. Packets can hop from one router to another until they reach one that's connected to a landline. The technology has also been used for permanent municipal Wi-Fi networks, including the one Google had built with Tropos equipment in its hometown of Mountain View, California.

Saudi Arabia's Communications and Information Technology Commission appointed an Internet service provider, Bayanat Al-Oula, to provide the temporary network. It was rolled out in less than 60 days with no help from Tropos personnel, Barton said. Aptilo Networks, a wireless-management software and services company based in Stockholm, is running the network as a managed service from its offices in Malaysia. This also helped Bayanat get the infrastructure up and running quickly, said Per Knutsson, Aptilo's co-founder and director of product development. Aptilo is handling user authentication, security, customer-support calls and other features, as well as setting up the portal visitors use to register for the network.

Aptilo and Tropos are no strangers to temporary Wi-Fi networks. Aptilo has managed systems for large sporting events, and in 2004 Tropos built a network in downtown Redwood City, California, for a high-profile murder case. The trial of Scott Peterson, who was convicted of killing his wife and their unborn child, drew massive public and media attention. The county court where the trial took place set up a temporary network with five surveillance cameras and five meshed routers for its own security needs and for reporters who descended on the area for several months.

The Mecca network is made up of Tropos 5210 mesh routers, which use IEEE 802.11a for mesh connections and can support users with 802.11a, b and g devices, Barton said. Such networks typically require between 20 and 40 routers per square mile, she said.