Fragmentation Analysis For Scalable Wireless Local Area Networks

Introduction: Basics of OPNET IT Guru Academic Edition

This paper presents an in-depth analysis of the performance of various classes supported by ATM to attain Quality of Service (QoS). We incorporate a large network environment for analyzing the impact of the QoS classes CBR, VBR, ABR & UBR with regards to the FTP, E-mail & Database applications running on an ATM network. These applications are configured to execute in parallel with the Voice application. The simulations have been performed using the OPNET IT Guru Academic Edition v 9.1. Our experimentation results show that for the FTP application, CBR offers the minimum delay and is followed by VBR, UBR and ABR. For the Database application, all the classes of service perform almost similar, whereas for the E-mail application, the CBR service performs better and is followed by ABR, VBR and UBR in order.

Computer simulation is becoming increasingly popular among computer network researchers for performance modeling and evaluation of computer and telecommunication networks. This popularity is due to the availability of various sophisticated and powerful simulators, and also because of the flexibility in model construction and validation offered by simulation. While various network simulators (both open source and commercial) exist for modeling and performance evaluation of communication networks, OPNET is becoming popular network simulator as the package is available to academic institutions at no cost, especially OPNET IT Guru. This chapter aims to provide a tutorial on OPNET focusing on the simulation and performance modeling of IEEE 802.11 wireless local area networks (WLANs). Results obtained show that OPNET provides credible simulation results close to a real system.

Wireless communication provides users many benefits such as portability, flexibility, reduced hardware need and lower installation costs. Wireless local area networks (WLANs) for example allow users the ability to carry their laptops from place to place without any physical wires and without losing network connectivity.However, some amount of security risk is always associated with wireless networks. The most significant security risk for wireless technology is the potential outsiders have in gaining access to the communications medium, the communications medium being the air waves. Though WLANs provide the users with the option of roaming, this convenience is facilitated by broadcasting packets to anyone with compatible equipment within range of a transmitting device. This broadcasting of packets induces a compromise between convenience and security. Having an unsecured WLAN can result in a loss of service, or can be used as a staging area to launch attacks against other networks. The significant challenges faced today in securing wireless LANs are maintaining privacy, data confidentiality, and preventing unauthorized access using proper access control mechanisms.As wireless networking and security become more prevalent in the market, more and more computer science programs are incorporating courses in wireless networks or at the least, devoting a significant percentage of the advanced networking courses to wireless topics. As a result, in addition to industry practitioners, there is a growing interest among university researchers and faculty regarding tools used in monitoring and assessing security threats for wireless networks.This paper will demonstrate and evaluate a free and open source software tool, called Network Stumbler, used for monitoring and assessing security threats for wireless networks. Network Stumbler is a Windows-based tool that allows you to detect Wireless Local Area Networks (WLANs) using 802.11b, 802.11a and 802.11g. It has many uses:• Verifies that your network is set up the way you intended.• Find locations with poor coverage in your WLAN.• Detects other networks that may be causing interference on your network.• Detects unauthorized rogue access points in your workplace.• Helps aim directional antennas for long-haul WLAN links.• Can be used recreationally for WarDriving.

Recent demands on affordable, portable wireless communication and computation devices have resulted in exponential growth of wireless networks ranging from Wireless Local Area Networks (WLAN) and Wireless Wide Area Networks (WWAN) to Ad-Hoc and Sensor networks. The major goal of wireless communication is to allow users to communicate together and to have access to global network anytime anywhere. This has led to wide acceptance of infrastructure based cellular networks (WWANs) where mobile stations communicate with a centralized controller, often referred as Access Point (AP) that is connected to the wired networks. On the other hand, WLANs have appeared as dominant popular technologies in many venues including a local area such as an academic campus or an airport terminal. These wireless networks mostly rely on IEEE 802.11 Wi-Fi (Wireless Fidelity) technology and its various derived versions (i.e. 802.11a,b,g). IEEE 802.11 standard supports two operational modes: The infrastructure-based Wireless Local Area Networks (WLANs) and an infrastructure-less Ad-Hoc Networks. A WLAN (Conti, 2003) typically imposes the existence of an AP and normally is connected to the wired networks to provide internet access for mobile devices. Obviously, only one hop link is needed to communicate between mobile devices and AP. In contrast, there is no AP or infrastructure in Ad-Hoc networks. Any two stations can communicate directly when they are in the range of reception of each other. To this end, the stations may use multi-hop routing to deliver their packets to destinations. The ad-hoc protocols (Conti, 2003; Mohapatra & Krishnamurthy, 2005) are self-configured for address and routing in the face of mobility and the network topology may change in each configuration. The multi-hop wireless ad-hoc networks, or multi-hop wireless networks enable wireless networking in the environments where the wired or cellular connections are impossible, inadequate, or cost effective (e.g. battle field, disaster recovery, etc.). The popularity of internet over the last decades has resulted in rapid advancement of demanding applications. The Transmission Control Protocol/Internet Protocol (TCP/IP) (Stevens, 1994) is a well-known de facto protocol in developing today’s internet. Basically, TCP provides a connection-oriented and reliable end-to-end data delivery between two hosts in traditional wired networks. Since TCP is well tuned and due to its wide acceptance in internet, it is desirable to extend and adopt its functionality to wireless networks. On the

Wireless Local Area Network (WLAN) is an alternative in overcoming cabling problems in a local network. Often wireless network security that is installed still uses vendor default settings such as SSID, IP Address, remote management, DHCP enabled, frequency channels, without encryption, even user or password for wireless administration. How does a strong WLAN security system work? The most common security system applied to wireless networks at this time is starting from securing access points by applying the MAC Filtering concept, using WPA / WPA2-PSK security keys, and RADIUS server authentication. To see the quality of wireless LAN network security, how do you analyze the test of the existing security system in the network. The method that can be used in evaluating wireless networks is by testing the system by simulating forms of attacks on wireless networks with the Penetration Testing method. By carrying out 4 stages of research using the penetration testing method (i) the planning stage, (ii) the discovery stage, (iii) the attack stage and (iv) the report stage, from the attack stage (Cracking The Encryption, Bypassing MAC Address, Attacking The Infrastructure and MITM ) using Kali Linux got the results of four types of attacks carried out, only one of which was failed, namely the cracking attack type of the encryption on the RADIUS server due to using captive portal authentication

With the increasing popularity of the wireless network, the security issue for mobile users could be even more serious than it can be expected. Here it is need to search for new architecture and mechanisms to protect the wireless networks and mobile computing application. This paper focuses on intrusion detection and security consideration in wireless local area networks (WLANs) and also presents intrusion detection for WLANs, which gives a wireless intrusion detection system and its architecture consideration. A wireless IDS is similar to a standard, wired IDS, but has additional deployment requirements as well as some unique features specific to WLAN intrusion and misuse detection. Meanwhile, we discuss some issues with wireless networks and Intrusion detection solution to wireless networks.

Wireless Local Area Networks (WLANs) and Wireless Metropolitan Area Networks (WMANs) are two of the main technologies in wireless data networks. WLANs have a short range and aim at providing connectivity to end users. On the other hand, WMANs have a long range and aim at serving as a backbone network and also at serving end users. In this dissertation, we consider the problem of Medium Access Control (MAC) in WLANs and the placement of Relay Stations (RSs) in WMANs. We propose a MAC scheme for WLANs in which stations contend by using jams on the channel. We present analytic and simulation results to find the optimal parameters of the scheme and measure its performance. Our scheme has a low collision rate and delay and a high throughput and fairness performance. Secondly, we present a MAC scheme for the latest generation of WLANs which have very high data rates. In this scheme, we divide the stations into groups and only one station from each group contends to the channel. We also use frame aggregation to reduce the overhead. We present analytic and simulation results which show that our scheme provides a small collision rate and, hence, achieves a high throughput. The results also show that our scheme provides a delay performance that is suitable for real-time applications and also has a high level of fairness. Finally, we consider the problem of placing Relay Stations (RSs) in WMANs. We consider the Worldwide Interoperability for Microwave Access (WIMAX) technology. The RSs are used to increase the capacity of the network and to extend its range. We present an optimization formulation that places RSs in the WiMAX network to serve a number of customers with a pre-defined bit rate. Our solution also provides fault-tolerance by allowing one RS to fail at a given time so that the performance to the users remains at a predictable level. The goal of our solution is to meet the demands of the users, provide fault-tolerance and minimize the number of RSs used.

Wireless network security protocols are essential for enhancing security, privacy and confidentiality. However, network security protocols also require network resources in other to carry out authentication of users through the use of encryption keys and packet encryption. It is therefore relevant to investigate the effects of the amount of resources used by recommended wireless network security protocols in other to determine if user quality of experience and user quality of service is affected by the implementation wireless network security protocols. Our research investigates and examines the effect of security protocols on wireless network performance. The Wi-Fi Protected Access 2 - PreShared Key (WPA2-PSK) was used as the security protocol in focus while throughput was the network performance feature that was analyzed. Experiments were carried out which showed that throughput in a non-secured Wireless Local Area Network (WLAN) is a bit higher than throughput in a secured WLAN. Our research contributes to the future development of WLAN protocols with low network resource consumption in other to contribute to improved network performance.

The increasing demand for the coverage of high‐speed wireless local area networks (WLANs) is driving the installation of a very large number of access points (APs). Wireless mesh networks (WMNs) have emerged as a promising technology in the next generation networks to provide economical and scalable broadband access to wireless interconnection of multiple APs that manage individual WLANs in order to extend the coverage of the conventional single WLANs. In this paper, we develop a new analytical model to investigate the quality‐of‐service (QoS) performance metrics in WMNs interconnecting multiple WLANs. The model takes the phenomenon of communication locality into consideration. Extensive simulation experiments are conducted to validate the accuracy of the analytical model. The proposed model is then used to obtain the maximum achievable throughput, which is a key performance metrics in wireless networks. Moreover, we utilize the model to evaluate the impact of communication locality on network performance and investigate its effects on the optimization of integrated WLANs and multi‐hop mesh networks. Copyright © 2009 John Wiley & Sons, Ltd.

The complex and abstract theory of routing protocols can be clarified by doing some laboratories in testbeds. However, it is not always possible to setup an entire testbed containing multiple computers, switches and routers to strengthen student skills for time and cost reasons. Using GUI-based applications is an alternative way to improve the understanding of the complex algorithms involved in routing protocols, because graphics, images and animations can be easily transformed into knowledge. With a visual didactic approach, students can understand how routing protocols really work in a more intuitive and friendly way than using traditional approaches. In this paper, we focused on the teaching and learning of EIGRP, an advanced distance-vector routing protocol developed by Cisco Systems, using visual educational tools. To do so, we present well-known computational tools (Packet Tracer, Dynamips/GNS3, and OPNET IT Guru) and a new application that we developed (Easy-EIGRP), and discuss how they can be used to strengthen the teaching and learning of EIGRP.

Electronic learning has produced a comfortable, sophisticated, interactive and adaptable teaching model. Moreover, the consistent technical progress in this field allows the development of increasingly interesting applications [1]. We chose to select those elements to create an e-learning environment. This paper presents a model of the multi-tiered e-learning system based on Web Services. It shows architecture for implementing e-learning environment by taking into account quality of service (QoS) requirements namely traffic dropped, traffic received and packet end to end delay. However, there exists no known simulation approach on how to deploy a popular real-time network service such as e-learning system. This paper offers remarkable details on how to model and configure OPNET for such a purpose. The study has been carried out using OPNET IT Guru on 3 scenarios are suggested first before enabling any QoS mechanism at the routers, second apply class based weighted fair queuing using low latency queue (CBWFQ-LLQ) for video traffic and last scenario apply CBWFQ-LLQ for voice. The simulation results show that CBWFQ with LLQ for Voice Traffic has a superior quality than the other techniques. This model was tested with different number of learners. Results indicate that improvements caused by traffic differentiation, become more significant as the number of users increases.

Wireless local area network (WLAN) has changed the paradigm of communication and become ubiquitous. As the number of devices connected to wireless is increasing, it is therefore, essential to find vulnerabilities in the security of wireless networks. In this research WLAN security vulnerabilities are exposed in real time. WLAN security techniques (MAC filtering, Hidden SSID and WPA2) available to residential users were practically exploited. Tenda WiFi wireless access point was set up with MAC filtering, hidden SSID and WPA2 security mechanisms in different combinations in such a way as to add an additional layer of security to previous configuration. Kali Linux version 2017.1 was used as a platform to exploit WLAN networks in real time. In this research, the sensitive information broadcasted by WLAN was utilized to carry out attacks on wireless networks. A practical demonstration of exposing vulnerabilities in MAC filtering, Hidden SSID with MAC filtering and WPA2-PSK with hidden SSID and MAC filtering security mechanisms of AP was carried out in real time. It was observed that the existing security mechanisms were vulnerable. Researchers have exploited many security mechanisms of WLAN focusing upon a single parameter of WLAN security at a time. However, in this work, the three available security mechanisms were cascaded to produce a three layer security mechanism i.e. WPA2 with hidden SSID and MAC filtering. This cascaded model was exploited in real time.

Wireless local area networks (WLANs) have risen in popularity for in-car networking systems that are designed to make driving safer. Wireless mesh networks (WMNs) are widely deployed to expand the coverage of high-speed WLANs and to support last-mile connectivity for mobile users anytime and anywhere at low cost. Many recent measurement studies have shown that the traffic arrival process in wireless networks exhibits the bursty and correlated nature. A new analytical model is developed in this paper as a cost-effective performance tool to investigate the quality-of-service (QoS) of the WMN that interconnects multiple WLANs in the presence of bursty and correlated traffic. After validating its accuracy via extensive simulation experiments, the analytical model is then used to investigate the performance of the hybrid wireless networks.

The aim of this paper is to characterize the behavior of the UDP transport protocol, mainly in terms of throughput and average delay, over an IEEE 802.11b compliant wireless local area network (WLAN) from an experimental approach. Although performance evaluation of these kinds of LAN is being extensively discussed in the current literature, most of these studies are analytical or simulation-based and they do not consider the influence of channel impairments or link quality over network throughput. After an exhaustive measurement campaign, different performance parameters such as throughput, goodput, effective goodput, frame error rate, IT loss rate, delay and jitter have been obtained. This could be a preliminary analysis of the behavior of real-time traffic over WLAN infrastructures, such as streaming audio and voice transmission, services that are expected to undergo substantial growth in the coming years. All these studies and results have been developed in the context of the WINE (Wireless Internet Networks) project belonging to the framework of the Information Society Technologies (IST) programme, addressed to enhancing the performance of TCP/IP protocol over WLAN such as IEEE 802.11, Bluetooth and HIPERLAN/2.