VoIP Technology Confidential. Introduction Understanding Voice over IP For years, many different data networking protocols have existed, but now, data communications has firmly found its home in the form of IP, the Internet Protocol. All Rights Reserved. No part of this. Straight facts about IP telephony planning and deployment 1.
Introduction Enterprises are rapidly adopting IP telephony for cost savings, productivity.
The focus of the course is the design, operation,. Multi-protocol label switching MPLS enables a common IP-based network to be used for all network services and for multiple. Contents Foreword Preface Acknowledgments 1 Introduction 1 1. It is aimed at those who want to move. The key problems with IP voice services are maintaining the quality of the voice service. Cable Modems Definition Cable modems are devices that allow high-speed access to the Internet via a cable television network.
While similar in some respects to a traditional analog modem, a cable modem. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means without prior written consent of. It is a fundamental business and. Simwood Carrier Ethernet Simwood Carrier Ethernet is a high security, low latency means to connect sites or services either point-to-point or as a mesh.
We use a number of technologies on top of our own. Reduction of voice quality. Duplication or propagation or extracts. BusinessInteractive GmbH Page 1 of 19 4. Patton Electronics Co. Dobrota com. NGN Next Generation.
Computer Networks CS Dr. Ramana I.
T Jodhpur Dr. Hitachi Review Vol. VoIP holds great promise. Ann Earon, Ph. Sponsored by Vidyo By:S. Introduction Successful. The migration away from traditional multiple packet overlay networks towards a converged packet-switched. Log in Registration.
Search for. Size: px. Start display at page:. Molly Fisher 4 years ago Views:. Similar documents. He also has over More information. He also has over 15 years of experience in the More information. Offprint from News TABLE 2. Outdoor-to-Indoor and Pedestrian Pathloss Model This environment is characterized by small cells and low transmission power. Base stations with low antenna heights are located outdoors; pedestrian users are located on streets and inside buildings and residences. Vehicular environment This environment is characterized by larger cells and higher transmits power.
The base stations are connected to the core network by an IP backbone. There is a server backbone containing the voice server which is configured as the SIP server. The IP backbone, server backbone and the ASN gateway together represent the service provider company network. The green bidirectional dotted lines represent the generic routing encapsulation GRE tunnels. The cell radius is set to 30 kilometres. There are 10 nodes under the base station 2.
Voice call of PSTN quality is configured between these mobile nodes. The nodes participating in the same session are connected by the blue bidirectional dotted lines.
Simulation Results and Discussion The performance metric used to analyse the network performance is path loss, average throughput of the WiMAX network and packet end to end delay. We are interested to investigate the combined effect of terrain buildings, trees, etc. To investigate the combined effect of terrain and vehicular mobility, the terrains are simulated by choosing the terrain type in OPNET which is thereby selected by the simulator, based on the actual location and surrounding terrain of the transmitter-receiver pair.
Pathloss Path loss models are broadly classified into four groups namely free space, Suburban fixed, Outdoor to indoor and pedestrian, vehicular environment. Path loss due to various pathloss models in decibel. From the graph it is observed that the path loss for outdoor to indoor and pedestrian is the highest and the same for free space is the lowest.
This is due to the fact that the path loss value varies with the amount of reflection in the communicating path. As a mobile node moves from outdoor to indoor the number of reflections in the communicating path increases rapidly thereby causing huge path loss. Also, we see that the path loss for free space is the least. This is concluded in  that the path loss increases with the number of obstructions in the communication path. Free Space implies a terrain with no or very less obstruction. Hence, number of obstruction decreases and pathloss thereby is minimum.
Average Throughput This metric measure the amount of voice traffic and FTP traffic received in bits per second on an average for each connection. From Figure 2.
This is due to the fact that as the density of obstacles increases, the Line of Sight LOS gets affected. Thus the number of times the signal gets obstructed and reflected is more. This results in increasing attenuation and diffraction due to the building structures, trees or mountains. This results in packet loss thereby causing fall in the average throughput. Average Packet end to end delay This metric measures the time taken by each voice packet to travel from the mouth of the transmitter to the ear of the receiver and each FTP packet from the application layer of the sender to the application layer of the receiver, on average for each connection.
This is due to the fact that as the density of the building structures, trees or mountains increases, the number of times the signal gets obstructed and reflected is more thereby increasing attenuation and diffraction. Hence, the LOS between the transmitting and receiving nodes decreases.
This causes the mobile node to get disconnected from the base stations and thereby perform re-registration  to get re-connected to a base station. The registration procedure is time consuming and hence adds up to the packet end to end delay. With flat terrain model and very less or nil obstructions, the mobile node remains connected to some or the other base stations and thus the network scanning and registration process is avoided thereby causing less delay as shown in Figure.
Packet end to end delay in seconds 2. Conclusion The target of this work was to check the variation of the network performance due to varying pathloss and terrain models. The aim was to evaluate the effect of various path loss models over varying suburban terrains, on the basis of average throughput and packet end to end delay and path loss of Mobile WiMAX.
The reduction in Line-Of-Sight due to the terrain model of any area influences the network throughput directly by increasing the attenuation and diffraction losses, and indirectly affects the packet end to end delay by causing nodes to initiate network re-registration more frequently under fluctuating cell coverage. This is already mentioned in   .