Michal Halas

Effective packet loss estimation on VoIP jitter buffer

The paper deals with an influence of network jitter on effective packet loss in dejitter buffer. We analyze behavior of jitter buffers with and without packet reordering capability and quantify the additional packet loss caused by packets dropped in buffer on top of the measured network packet loss. We propose substitution of packet loss parameterP pl in ITU-T E-Model by effective packet loss P plef incorporating network jitter, a jitter buffer size and a packet size as additional input parameters for E-Model.

Computationally efficient E-model improvement of MOS estimate including jitter and buffer losses

In the article we propose a method of improving ITU-T E-model MOS estimate of VoIP call quality. The improvement consists of including the effects of network jitter as measured and distributed in RTCP packets; jitter buffer size at receiver and codec packetization settings as input parameters of E-Model. Our method uses Pareto/D/1/k system for modeling general VoIP input traffic stream interarrival times and jitter buffer behavior resulting in additional packet loss. Consequently we propose the inclusion of jitter buffer size, codec packetization and network jitter into E-Model by means of substitution of existing Ppl (packet loss) parameter for Pplef (effective packet loss) in computationally effective manner suitable for real-time MOS estimate without the need of capturing large packet traces from the network and performing estimation of Hurst parameter or using other means of traffic statistics description in advance.

Performance measurement of encryption algorithms and their effect on real running in PLC networks

This article and its outputs reveal the need of search for the most suitable encryption algorithm used in PLC devices, the procedure for simulating performance of encryption algorithm and practical measurement of throughput in the PLC networks.