Distributed Real-Time Measurement of VoIP Parameters

 

Tien Van Do, Ph.D, Department of Telecommunications, BUTE

Zsolt Pándi, Department of Telecommunications, BUTE

{do,pandi}@hit.bme.hu

 

 

Presently there are a growing number of real-time applications (VoIP, streaming audio and video) on the Internet, which is due to the economic reason that the Internet is a cheap medium to realise these applications. The provision of real-time applications in the Internet is not straightforward because the presently applied service model is Best Effort. Therefore, the QoS (quality of service) of real-time applications is not guaranteed. Since real-time applications often use UDP as a transport layer protocol, their generated traffic is not friendly with other traffic types.

In order to provide appropriate QoS, new solutions are needed. On the one hand, an appropriate technology (QoS architecture) should be chosen. On the other hand, network operators should provide traffic engineering solutions for the deployed network. One very important task, which determines the success of traffic engineering, is the performance measurement of applications and networks. Measurement procedures can be categorised as follows:

1.        Active measurement: a traffic generator injects artificial traffic into the network in the direction of a receiver. Data is collected both at the generator and at the receiver.

2.        Polling: ask network devices about statistical parameters by the use of SNMP.

3.        Passive measurement, where special hardware and software tool is needed to passively capture traffic.

Generally passive measurement is the most accurate method compared to the other ones. The hardware used for capturing network traffic is called a protocol analyser. As protocol analysers are basically applied for finding errors, their statistical services supplied by vendors are rather poor and, after all, not adequate for supporting the service planning and provision of IP networks.

Our project aims at the development of a distributed measurement methodology and enhancement of services of the commercial protocol analyser family by RADCOM Inc.

The scientific aims of the project are defined as follows:

1.        Development of a multi-point measurement method to measure the performance parameters of VoIP and real-time applications.

2.        Proposal of a traffic engineering method in order to provide good quality of service for VoIP and real-time applications.

Those aims will be embedded in the development of a software package aiming at both national and international commercial markets.