Introduction to simulation and SLAM II (2nd ed.)
Introduction to simulation and SLAM II (2nd ed.)
Measured performance of an Ethernet local network
Communications of the ACM
Digital Coding of Waveforms: Principles and Applications to Speech and Video
Digital Coding of Waveforms: Principles and Applications to Speech and Video
Proceedings of the 11th communications and networking simulation symposium
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A study of mixed voice and data on a local area network under the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is presented. The study determined the feasibility of using multirate voice coding to control the traffic intensity on the network. By decreasing the voice coding rate for short periods of time (and thus the voice quality) when network traffic increases, a larger number of voice users can be realized. The premise is that short term voice quality can be traded for increased throughput on a CSMA/CD network. Collisions per millisecond is found to give a good indication of the traffic on the network. A feedback equation is used to set the voice coding rate, based on the measured collisions per millisecond. The coding rate determined from the feedback equation is rounded to one of four possible coding rates; other rates are clearly possible. The voice coding rates chosen were 48, 40, 32, and 24 kilo-bits-per-second. The simulation results show that approximately 10 additional voice users can be added to a 1 mega-bit-per-second network when the multirate algorithm is used.Results are given relating the packet delay to the collisions per millisecond. A comparison between multirate and non-multirate is given. An indication of the voice quality for the multirate system is also discussed. The multirate load control algorithm provides a way to increase the amount of voice traffic on a CSMA/CD network without increasing the line capacity.