Voice and Data Session Capacity over Local Area Networks

We analyze the effects of adding voice traffic to a packet switched network. We develop and validate separate simple and general analytical models for data and voice traffic and then combine them. Our analytical models assume no particular MAC layer and no priority of service. We analyze the effects on the average voice packet delay of the number of voice and data sessions, packaging of multiple voice frames in a single packet, contention at the MAC layer, and LAN utilization. Our first goal was to develop a model which can predict the number of real time voice sessions which can coexist with (TCP) data sessions. By appropriately parameterizing the model for narrowband voice codecs like G.723.1, we find some very interesting results. First, we find that hundreds of such voice sessions can share a 10 Mbps Ethernet link while maintaining appropriately low delays (below 30 ms). (See Figure 5) Next we see the surprising result that with as few as 5-10 simultaneous data sessions, the number..