School District Replaces VoIP with TDMoIP

The City of Spokane, Washington invests in its children’s education. Reflecting this commitment, citizens of Spokane approved a bond initiative to allocate their tax dollars to upgrading the school system’s voice and data infrastructure.

The bond initiative resulted in E-MAN (Educational Metropolitan Area Network): a new Gigabit Ethernet IP-based network designed to link all Spokane elementary and secondary schools with local and state colleges and universities over fiber. The educational goals of the E-MAN are to bring high speed filtered Internet, share data among the different educational communities and buildings and enable voice and videoconferencing among all educational institutions. The Spokane Board of Education originally considered SONET for the infrastructure but eliminated this option because of its cost and complexity. Finally, Gigabit Ethernet was selected because of its high performance, simple installation and maintenance, and affordability.

Spokane School District 81 (SD81) was the first to install a Gigabit Ethernet network. The SD81 E-MAN currently connects 53 schools, at distances of up to 12.5 miles (20 kilometers). The fiber network supports both the voice and data needs of the district, saving thousands of dollars a month on Centrex and Frame Relay services by transmitting voice and data over shared media. The fiber extends into each classroom, with copper to the desk for data and phone connections. Thanks to the new hybrid infrastructure, the school district has seen remote server backup times drop from over two hours to less than two minutes. Whole classes of students on computers can access a Web site at the same time without undue delays.

Voice over IP (VoIP) gateways were originally installed to move voice over the network. This led to several unforeseen problems such as echo, delay and PBX interface issues that slowed the implementation process. RAD’s IPmux gateway provided the best solution for T1 trunk replacement. It converts T1 or E1 voice and data streams into packets for transmission over IP and Ethernet-based networks (TDM over IP). In the SD81 network, it connects the PBX in each school to the central PBX, for delivery of traditional voice communications over the same IP infrastructure that is used for data. It is superior to VoIP in that it supports modems and faxes at full speed and H.320 video, ATM, Frame Relay and ISDN over IP – for less than 30% of the price. In addition, every classroom has a phone with enhanced 911 emergency services capability that displays the classroom number on the receiving telephone.

“We are able to provide a voice-over-the network system with none of the compromises of most VoIP systems,” says Jim Wilson of Tylite Inc., the systems integrator for the Spokane E-MAN project. “The IPmux lets us provide a complete solution. It sounds just like the normal telephone. Even music-on-hold works,” he says. “We are experiencing excellent quality voice with the new network,” confirms Dennis Schweikhardt, Technology Infrastructure Manager for SD81.

RAD has recently developed the IPmux-8, a more robust version of the IPmux-4.