H.323 wins major backing >BY Chris Bucholtz West Coast Bureau Chief >TX In a move that could greatly increase the use of the Internet for voice calls, Microsoft and Intel today launched an aggressive move into the Internet telephony market, asserting tha

After completing its acquisition of StrataCom earlier this month, Cisco Systems hit the ground running last week, announcing the availability of its asynchronous transfer mode inverse multiplexing support for its StrataCom BPX switches and Axis devices. The Inverse Multiplexing for ATM (IMA) modules will let carriers and ISPs offer sub T-3 ATM services to their customers. The gap between T-1 (1.544 Mb/s) and T-3 (45 Mb/s) has been a thorn in the side of many users. The IMA modules support two applications. Carriers can deploy a module for trunking between BPX switches and in their Axis shelves to support ATM inverse multiplexing services, said Andrew Greenfield, director of service provider marketing in Cisco's wide area network switch business unit, formerly StrataCom. The modules are based on work the ATM Forum has completed on a pending specification regarding ATM inverse multiplexing. The specification is expected to be finished around the end of the year, Greenfield said. "We are not expecting radical changes because we waited for the major work to be completed." Indeed, StrataCom has worked heavily with the ATM Forum in developing the specification, said Jay Pultz, research director at Gartner Group, a Cambridge, Mass.-based consultancy. IMA is as close to the specification as anyone can get at this point, he said. LDDS WorldCom is not concerned that the specification is pending because Cisco has committed to offering its customers firmware and software upgrades to comply with the specification, said Russ Ray, vice president of engineering at the interexchange carrier. LDDS WorldCom is testing the IMA modules in its laboratories. "We have numerous customers that have requirements for more than DS-1, but not enough demand for DS-3 and they haven't hit the economic crossover point where DS-3 is a better choice," Ray said. "IMA fills the gap in bandwidth requirements between T-1 and T-3," Greenfield said. Cisco has made its IMA specification available to vendors at no cost. A few that have it are ADC Kentrox, OnStream Networks and Network Equipment Technologies. Carriers are limited in rolling out services, however, because customer premises equipment that supports IMA doesn't yet exist. ATM inverse multiplexing technology requires a multiplexer or access device reside at the user's location to receive the multiplexed T-1 lines. "The availability of CPE is an issue," Pultz said. Yet carriers that put the technology into their networks have a head start, he noted. A real case for ATM inverse multiplexing can also be made internationally, where T-3 lines are not commonly available and are outrageously expensive, Greenfield said.