Voice Streams Research Articles

A compatible fixed-frame ISDN gateway for broadband metropolitan networks

A method (referred to as I-SWIFT) is presented for integrating the flow of synchronous voice streams into existing broadband cable systems. The interface between the integrated voice subnetwork and the cable system is realized by a metropolitan area gateway (MAG) implemented at the broadband cable headend. In I-SWIFT, an intelligent scheduling algorithm in the MAG dynamically allocates channel bandwidth using modified data switch-filtering techniques. The MAG accomplishes this by establishing a fixed voice frame (with realignment) which is implemented in an upwardly compatible fashion with respect to the existing carrier-sense multiaccess communication with collision detection (CSMA/CD) data stations. Thus, previously installed stations require no modification. It is shown that for typical system design parameters, the I-SWIFT gateway approach can achieve much improved performance over previous compatible voice/data integration methods.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Characterizing Superposition Arrival Processes in Packet Multiplexers for Voice and Data

This paper analyzes a model of a multiplexer for packetized voice and data. A major part of the analysis is devoted to characterizing the aggregate packet arrival process resulting from the superposition of separate voice streams. This is done via the index of dispersion for intervals (IDI), which describes the cumulative covariance among successive interarrival times. The IDI seems very promising as a measurement tool to characterize complex arrival processes. This paper also describes the delays experienced by voice and data packets in the multiplexer using relatively simple two-parameter approximations.