Design and Simulation of Wireless Local Area Network for Administrative Office using OPNET Network Simulator: A Practical Approach

Wireless local Area Network (WLAN) is a networking standard that links two or more devices with the use of wireless signal (radio frequency). It is based on the IEEE 802.11 standards (IEEE Standard 2007). Its advantages over the traditional wired technology, includes: reduction in wires, mobility and flexibility. It can be deployed in ad-hoc (infrastructure less) and infrastructure based, which uses access point as its central coordinating facility. In this paper, infrastructure-based WLAN is used. In this case, there is an access point (AP) and stations/clients (that could be mobile). This BSS connects to other neighbouring BSSs through a high speed back-bone, the back-bone then connects to the ISP through a modem for internet services. As a result, we designed and simulated WLAN and identified the key network performance parameters (such as delay, throughput, packet drop, etc) that must be addressed to guarantee optimal service delivery Keywords: WLAN, QoS, Broadband, Bandwidth, Throughput

Investigating the QoS of Voice over IP using WiMAX Access Networks in a Campus Network

VoIP is a very rapid evolving communication technology which supports transportation of voice data via IP based networks. In parallel, IEEE 802.16e standard based WiMAX is a new emerging access technology and the first generation of 4G broadband access wireless technology with an enhanced in-built quality of service (QoS) provision with many benefits including cost reduction, high quality as well as other value added network service solutions especially for communications Service Providers with emphasis on real time services. WiMAX promises manifold benefits in terms of optimal network performance across a long distance in contrast to other wireless technologies such as Wi-Fi and 3G cellular technologies. Hence, this research attempts to identify some of the network performance parameters that Service Providers will focus on to develop a VoIP over WiMAX communication tool that will serve as a voice communication broadband replacement technology to old circuit-switch voice communication. This study adopted a simulation-based network performance analysis to investigate the effects of the application of different voice encoder schemes on QoS of VoIP system deployed with IEEE 802.16e standard WiMAX network. Through different network simulation experiments using realistic network scenarios in OPNET environment, this research provided an in-depth network performance comparative analysis of VoIP over WiMAX using performance parameters which indicate QoS such as voice jitter, voice packet ETE delay, packet-sent-packet-received, WiMAX network delay, voice packet delay variation and throughput. The obtained simulation experiment results indicated that choice of suitable codec scheme can affect the QoS of VoIP traffic over WiMAX network. The results also indicated that the choice of suitable voice encoder scheme with a small number of voice frame-size per packet have a significant impact over VoIP traffic performance when deployed with WiMAX access technology. Keywords: WiMAX, QoS, End-to-End delay, Jitter, IEEE 802.16e, PSTN, OPNET, Simulation, Wi-Fi, Code

Improved QoS Support for WiMAX Networks: A Survey

Quality of Service (QoS) is considered as the backbone of any Broadband media access network of which WiMAX is not an exception. Immense work is being carried out in the academia in this area. The goal is to come up with improved QoS to support different traffics in WiMAX network. This work presents a survey of the various current states-of-the-art QoS schemes that could be utilised to realise a guaranteed QoS necessary for effective general high WiMAX access network performance. We concentrate on three approaches. The approaches include Hierarchical Scheduling Framework for QoS in WiMAX point-to-point Networks, this approach divides scheduling scheme into three different Tiers. Others are Cross-layer Optimization Framework and Resource Allocation for Improved QoS in WiMAX; and On-demand Bandwidth Allocation for WiMAX. Keywords: WiMAX, QoS, Scheduling, Broadband, Bandwidth, Throughput

Study of the impact of dielectric constant perturbation on electromagnetic wave propagation through material medium: MathCAD solution

We present the study of dielectric constant and its influence on wave propagation through an inhomogeneous material medium via mathcard approach. Mathcard was used to solve numerically the wave equation involving a perturbation in term of dielectric constant  imposed on scalar wave equation.  The equation was reduced to a form suitable for numerical solution using mathcard on which we applied various values of dielectric constant perturbation for three regions or electromagnetic spectrum VIS UV, optical near infrared region. The correlation between the field profile and the propagation was analyzed. Keyword: dielectric constant, perturbation, numerical solution, mathcard, scalar wave equation, electromagnetic spectrum, correlation, propagation distant, material medium

Prevalent Network Threats and Telecommunication Security Challenges and Countermeasures in VoIP Networks

Due to the recent global popularity gained by VoIP network while many organisations/industries are employing it for their voice communication needs, optimal security assurance has to be provided to guarantee security of their data/information against present day teeming security threats and attacks prevalent in IP-based networks. This research paper has critically investigated and analysed most of the security challenges associated with VoIP systems and traditional IP data networks; and has proposed several defence measures which if designed and implemented will prevent most (if not all) of the security threats plaguing these networks. Keywords: Network security, VoIP, Computer attack, Security threats, SIP, H.323, Defence measures, IPSec

Use of Information Centric Network (ICN) as a viable Alternative to Traditional IP Network in Forwarding Mechanism: A Practical Approach to Preventing DoS using Bloom Filter Packet Forwarding

This paper focuses on identifying the benefits of using ICN network as an alternative to forwarding mechanism in place of the traditional IP network. The ICN network uses an In-packet Bloom filter as the forwarding identifier, where a complete analysis of the false positive probability is carried out. The formulas used in the false positive analysis include the classical formula, Bose formula and the experimental formula. However, this work does not involve the actual implementation of the Bloom filters on the router, but rather an explanation of the possibility is given. In the experimental program, we used MATLAB to generate a set of links and encode them as Bloom filters and used a function known as setdiff, which extracts the number of links to be tested from the actual links array. Keywords: Information Centric Network (ICN), IP Network, DoS, DDoS, TCP/IP Protocol Suite

Denial of Service (DoS) in Internet Protocol (IP) Network and Information Centric Network (ICN): An Impediment to Network Quality of Service (QoS).

This paper compares and analyses the Denial-of-Service attacks in the two different Network architectures. The two architectures are based on different routing approaches: Hop-by-Hop IP routing and source-routing using Bloom filters. In Hop-by-Hop IP routing, the packet header contains the address, and the route is decided node by node. Forwarding in this method requires a node to have a routing table which contains the port through which the packet should traverse depending on the address of the destination. Instead in source-routing, the forwarding identifier is encoded with the path a packet should take and it is placed in the packet header. The forwarding identifier in this approach does not require a forwarding table for look ups like the IP routing; it relies on Line Speed Publish/Subscribe (LIPSIN) forwarding solution that focuses on using named links not nodes or interfaces. The forwarding identifier encompasses a set of Link ID’s which specifies the path to the recipient and they are encoded in a Bloom filter. The In-packet Bloom filters serve as both path selectors and as capabilities, and they are generated dynamically. However, this thesis is going to focus on the latter network technology by looking at both its benefits and drawbacks as well as analysing the possibilities of having a Denial of service attack. Keywords: DoS, DDoS, TCP/IP Protocol Suite, ICMP flood, E-mail Bomb, Ping of Death, TCP and UD

Comparative Analysis of QoS Guarantee on IEEE 802.11e and IEEE 802.11g Wireless Local Area Networks

For this project, we propose to compare the 802.11g and the 802.11e Wireless Local Area Networks (WLANs). The 802.11g WLAN standards are good for data applications. However, the 802.11g standard is not well-equipped to deal with the intended delay and bandwidth requirements of multimedia applications, such as video and voice over wireless IP. For this reason, an approved amendment (802.11e) was added to the IEEE 802.11 standard. The 802.11e implements Quality of Service (QoS), which enables features through changes in the Medium Access Control (MAC) layer. The performance of 802.11e will be evaluated using OPNET simulation and compared with the 802.11g WLAN standard.   Keyword: QoS, IEEE 802.11, WLAN, MAC, OPNET, WiFi, CSMA/CA

Qualitative Investigation of the Performance of Real-Time Application of IEEE 802.16e standard WiMAX Relay Networks

The ability of an application to adapt its behavior to changing network conditions depends on the available bandwidth, throughput, delay and packet loss in a network path. These are of major importance in congestion control, streaming applications, quality of service verification, relay selection and many other areas in WiMAX relay stations. Mobile WiMAX, which is based on the IEEE 802.16e standard, provides support for and enables full mobility to users. In an effort to optimize and enhance the overall network throughput, this paper will propose a mobile relay framework. WiMAX is based on the IEEE 802.16e standard, and can support various types of handovers, while allowing for full mobility from the user endpoint. Different methodologies were used to compare different aspects of WiMAX relay stations including throughput, delay, SNR and network load. OPNET modular was used to develop and measure these set of network performance metrics. To accurately measure and evaluate the aforementioned network parameters we employed techniques that were able to process large amounts of data, this aided in provision of much more informed recommendations as to the type of relay station modes that should be installed engender enhanced, improved and optimal Quality of Service (QoS) within the network perimeter. This paper measured the overall network throughput, delay, SNR and network load of relay networks comprising mainly of multimedia applications. Keywords: WiMAX, QoS, Relay Station, Simulation, Topology, Throughput, Delay, Packet Los