Avaya Inc. this month announced a new subscription-based monthly voice over IP (VoIP) service for medium and large businesses that allows them to avoid complicated equipment installations.

The “worry-free” approach, called Avaya On Demand, is unusual for an equipment provider and is now more commonly offered by service providers, according to George Humphrey, director of Avaya’s new program, which was announced at Interop Las Vegas 2006.

Lucent Technologies and Nortel Networks offer VoIP services for carriers, who then sell the service to enterprises.