SUNYIT. Reaction Paper 2. Measuring the performance of VoIP over Wireless LAN

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1 SUNYIT Reaction Paper 2 Measuring the performance of VoIP over Wireless LAN SUBMITTED BY : SANJEEVAKUMAR 10/3/2013

2 Summary of the Paper The paper s main goal is to compare performance of VoIP in both LAN and WLAN. This is done by examining how the communication protocol performs in the different network setups and analyse the results obtained. The tools used in conducting this analysis include OPNET.OPNET is a software which provides performance analysis of computer networks and the applications. Some of the entities addressed by the project include VoIP over WLAN using frame relay including metrics throughput and traffic dropped, point to point and then compare these two against the VoIP over WLAN. The project includes collecting the performance statistics, measurement of lost packets, delays and throughput. All these are necessary to determine the VoIP quality over WLAN. In conducting this project some of the significant parameters considered include voice payload size, packet size, packets per second, number of generated packets and packet duration. In the statistics collected of the stimulation, packet loss was found out to be the main reason for voice quality depreciation. The simulation was run in different scenarios such as Baseline: Basic and used as a starting point of reference.no QoS implemented QoS : showed the impact of implementing e in a wireless network that was using VoIP After this simulation the two scenarios results were compared to measure the effectiveness inorder to develop a new baseline to be used with the other scenarios. QoS heavy traffic scenario: Network performance was tested during peak time and downtime. The simulation was done also in a wired network so as to identify the bottleneck areas in WLAN. 1

3 The model consisted of star topology for all the scenarios with frame relay for QoS heavy traffic and point to point connection for QoS PPP. Each end of the connection consists of a subnet. Within each subnet is a WLAN environment and LAN environment in the case of the wired connection. The WLAN consisted of 3 access points and 5 work stations in each of the access points. All these access points were connected through the switch. The switch is then connected to two servers, one for handling the VoIP traffic and the other for FTP and HTTP. The WLAN is connected to the frame relay using a router. The work stations were connected to the switch via 100baseT cables. Basic Parameters for the model Frame Relay WAN model and Point to Point WAN model are connected using T1 line at speeds up to 1.54Mbps.In the five work stations at each access point, 3 were fixed wireless workstations and two were moving stations. The work stations generated traffic across the frame relay and traffic within the WLAN environment. Applications which were created for the traffic included voice as VoIP is the significant parameter. Other applications included , file transfer, file print, web browsing and database access. For each of the applications there was heavy and light usage. This enabled to simulate the difference between peak time and down time. When voice traffic was sent over QoS and Baseline to see if QoS with e should be deployed or not, it was found that less bytes per second were lost also there was less delay and almost no jitters as compared to baseline. Hence it was found out that e could be implemented in testing VoIP over frame relay. QoS vs QoS heavy traffic. Using frame relay To measure impact of traffic volume a simulation was created which generated more traffic. This was to test the threshold of voice quality. Due to heavy traffic about 6000Bps more of voice traffic was lost indicating that high volumes of data can deteriorate the voice traffic. Also the delay and jitter were worse in this high traffic scenario. But the interesting fact is that neither delay nor jitter affected the call quality, it was the dropped traffic that affected it. The conclusion from this simulation was that the problem was with frame relay. It took in more traffic than it could accommodate which resulted in the dropped traffic. The reason for loss of packets was that as frame relay used packet switching technology which is ideal for data but not voice. Hence frame relay is the major limitation and not the WLAN. 2

4 QoS vs QoS heavy traffic. Using point to point connection. When the frame relay was replaced by point to point T1 line it received higher voice traffic than both baseline and QoS with frame relay the main reason being the dropped traffic by frame relay. The jitter was similar to frame relay. There was no packet delay variation in point to point whereas frame relay had an average delay variation. Also the WLAN average throughput was about bps which was higher than the one with frame relay. But average WLAN delay was higher in Point to point than in frame relay. Conclusion It can be seen from the analysis that point to point has more advantages than frame relay however the advantages are affected by the cost distance and speed of the connection. Point to Point could give better QoS but frame relay is cost effective. The significant observation is that when implementing an optimized VoIP network point to point WAN connection should be used with an e LAN. The simulation results showed that QoS on e can be optimized using the priorities and provide real time service for voice. This project was completed using the OPNET software. It is software which is completely dedicated to point out the performances of the networks. Hence by purchasing this software we will be able to complete this project. The work can be repeated but with some knowledge of this software, because it is necessary to make the models for which we will perform the simulations. This project can be redone but with some effort as there are many parameters that need to be considered when designing the model. Otherwise we will not be able to incur any information from the results. The research paper gives detailed graphs which readily makes it easy to identify the results. The paper titles performance of VoIP over wireless LAN and has considered connection oriented and connection less communications. It uses frame relay and point to point to give its output but there are many other connection types it has ignored to take into consideration like ATM and TCP. Hence by going into other communication technologies we will be able to get wider information with regard to the performance of VoIP over these networks. This paper has addressed the necessary parameters which are required to calculate the performance of VoIP over the WLAN. The detailed graphs and the table which gives the results make it easy to understand how different connection types have an effect over the 3

5 VoIP QoS. But I feel that by including other connection types this project would have been able to give a more comprehensible output. It has narrowed the research to two types of connections. We can extend the research by remodeling. Making the network bigger and including more pcs and then connecting with ATM or TCP and finding the results. 4