Google (Nasdaq: GOOG) confirmed Wednesday it has partnered with the ISP EarthLink Inc. (Nasdaq: ELNK) to compete for a contract to build San Francisco's municipal WiFi network. (See Google, Earthlink Bid on WiFi.)

Google and EarthLink submitted one of seven responses to a request for proposal (RFP) from the city, a spokesman says.

Google and EarthLink submitted separate proposals to the city during the previous phase of the vendor selection process last fall. Google's plan to offer free, ad-supported WiFi remains in the Google/EarthLink proposal, but an option for consumers to buy a higher tier of broadband service from EarthLink for around $20 has been added in. (See Municipal Broadband Networks.)

“In this proposal, Google will provide a free WiFi service citywide and EarthLink will serve as the premium service provider,” Google’s Megan Quinn said in an email to Light Reading Wednesday. (See Google Backlash Builds.)

According to the Google/EarthLink proposal, the free access would deliver a throughput of "300 Kbps for users citywide." The paid service tier would deliver "best efforts 1Mbps downstream and upstream" and would be priced at "around $20.00 per month." A number of competing ISPs would offer access over the network, the proposal says.

The Google/EarthLink alliance could have far-reaching consequences for EarthLink if things go well in San Francisco. (See Google's Ad-Mad Network .) Some observers believe San Francisco is but the first of many major cities to which Google would like to roll out free, ad-supported WiFi. (See Google's Own Private Internet and Google Cubes.)

“By coming together to leverage the strengths of both companies, we will be able to offer services to different customers on the network that fit with their own individual needs and wants,” EarthLink VP of municipal networks Donald Berryman says in a statement. (See Wireless Mesh Test Gets Underway.)

Google's chances of winning in San Francisco might be helped by EarthLink's recent momentum in the municipal WiFi world. (See EarthLink Hooks Up Philly.) EarthLink has already won high-profile municipal WiFi contracts in the cities of Philadelphia and Anaheim, Calif., and is competing for several others.

Given the complexity of municipal wireless networks, it’s no surprise that partnerships are forming even before the contract has been awarded, says analyst Esme Vos of MuniWireless.com .

The hardware element of such networks include everything from base stations to switching equipment to backhaul gear. Software elements include such things as Internet access, various broadband services, and billing and other back-end functions. (See Poll: RBOCs Fuel 'Broadband Gap'.)

The Google/EarthLink proposal calls for Tropos Networks Inc. to provide wireless mesh network equipment. (See Gorillas in the Mesh.) Motorola Inc. (NYSE: MOT) is named in the proposal to provide the backhaul equipment that moves wireless traffic from the WiFi nodes to the access towers.

“When you look at EarthLink they partner with all kinds of people,” Vos says. “EarthLink’s an ISP, they’re not a systems integrator – so they would need somebody to go in and set up the nodes and somebody to put in the back-end software.”

San Francisco chief administrative officer Ron Vinson told Light Reading Wednesday that his office received a total of seven competing proposals. (See Coalition Calls for Community Broadband.)

Competing with the Google/EarthLink combo will be MetroFi Inc. , Communication Bridge Global, NextWLAN, Razortooth Communications, SF Metro Connect (a partnership of SeaKay, Cisco Systems Inc. (Nasdaq: CSCO) and IBM Corp. (NYSE: IBM)), and one other unnamed player whose response came in late. (See SF Gets 6 Muni WiFi Bids.)

Vinson says an RFP review panel is now coming together to evaluate the proposals. The panel hopes to arrive at a finalist by early April, Vinson says, at which time negotiations over financial terms would commence.

Google and EarthLink estimate that the San Francisco network could be built in six to 10 months, barring any unforeseen problems.

— Mark Sullivan, Reporter, Light Reading