Teleperformance Gets Three 2 Mbps Links for the Price of One

It's mathematical: Call centers have a telecom bill proportional to their volume of activity, if not exponential. This is especially true when the call center is split among sites located several hundred kilometers apart. The case of Teleperformance illustrates this technical-economic constraint. The company wanted to extend the capacity of its call desk, located in a Paris suburb, from 30 to 90 workstations. The only problem was that the first point-of-presence (POP) was located at its site in Rennes, some 300 kilometers (over 190 miles) away. Up until that time,telephone calls between the two sites passed over a 2 Mbps MultiLAN service leased line from France Telecom. That link, however, was already overloaded, with no possibility of adding 60 more telephone channels. To control costs, Teleperformance did not consider leasing other MultiLAN circuits.

It was therefore necessary to find a solution around the PBX installed near Paris. The Avaya switch used there does support a voice compression card,but the capacity is limited to handle 90 telephone channels. Moreover, Teleperformance was well aware of the limits of such an extension, having already installed it on other switches. Dynetcom, the call center’s network and telecom integrator, therefore proposed RAD Data Communications’ Vmux voice trunking gateway. “Two weeks after the first commercial proposal, the Vmux units were operational in the network,” states Fabrice Douvnot, Technical Coordinator of Teleperformance’s Service Division. “We then needed three or four days of fine tuning to optimize management for noise and silence suppression,” he explains. The resulting configuration at the suburban Paris site includes an Avaya PBX serving three E1 lines connected to the RAD Vmux. The Vmux concentrates the first three primary ISDN lines over an E1 emulated circuit, via RAD’s ACE-202 ATM concentrator installed by France Telecom. A similar configuration exists at the Rennes site, which is equipped with an Avaya G3r PBX.

 

Since both devices came from the same manufacture,interoperability was not a problem. Nor was there any problem of interoperability between the Avaya PBXs and the Vmuxes, because these multiplexers operate on the E1 standard. The only stumbling block between these two systems was the compression rate. “Avaya recommended a lower compression rate,while Dynetcom insisted on RAD’s technical specifications,” Douvnot adds. “And it was right to do so, because the Vmuxes are now compressing to their maximum capacity.” Jean-Maurice Pourcharesse, Systems and Network Consultant at Dynetcom,agrees. “The transport of the 90 voice channels, along with a 64 kbps proprietary signaling channel,uses only 35%of the bandwidth in the MultiLAN circuit. This provides Teleperformance with the option of adding four E1 lines.”

Teleperformance does not plan such an expansion of this application for logistical reasons, since the future extension of its call desk will not be able to exceed more than 30 additional workstations. “For that reason, it will be enough to add one more E1 line to our two PBXs, Douvnot predicts.“ On the basis of the operational statistics provided by Dynetcom, we will preserve the same quality of service on the MultiLAN network,” he adds. For the time being, Teleperformance is amply satisfied because the Vmux enables it to save the monthly leasing charges of two additional MultiLAN circuits at €5,200 per circuit per month, not to mention setup fees of €4,400.“ Based on these recurring costs, we look forward to the RAD solution providing a return on the investment within a few weeks,” Douvnot concludes.