National regulator the FCC has ruled that AT&T Mobility and Verizon Wireless must allow their networks to be used by smaller competitors for mobile internet services. The watchdog voted 3-2 in favour of the measure, with Democrats for the plan and Republicans against. Network sharing was already mandatory for voice calls, but voluntary for data traffic. However, under the new rule AT&T and Verizon Wireless are now required to strike data roaming agreements ‘on commercially reasonable terms’ with smaller operators. Carriers unable to reach agreements may appeal to the FCC.