A STUDY ON THE BILL OF ENGINEERING MEASUREMENT AND EVALUATION OF A WIRELESS LOCAL AREA NETWORK IMPLEMENTATION

ABSTRACT

This seminar paper extensively discusses Wireless Local Area Network as an alternative to Cabled Local Area network (LAN). The paper classifies networking into three major parts (i.e Local Area Network-LAN, Metropolitan Area Network-MAN, Wide Area Network-WAN). It also presents Wireless Local Area Network (WLAN), Wireless Wide Area Network (WWAN), Personal Area Network (PAN), Home Area Network (HAN), Storage Area Network (SAN), Enterprise Area Network (EAN), Virtual Private Network (VPN) and lastly, Campus Area Network (CAN) as further classification of networks based on the initial three major classifications. It also describes the implementation of WLAN by using one of the computer laboratories of Dr. Olagunju’s Computer Centre of Federal Polytechnic Offa as a case study. The standard WLAN is carried out using 15 personal computers and other network devices. The circuitry structure and cost analysis are also presented.

CHAPTER ONE

1.1 Introduction

This seminar paper is on Wireless Local Area Network, it starts by looking at the basics of networking since WLAN is an extension of, or alternative to, LAN which is one of the major categories of network classifications. There is also Wireless Wide Area Network which is an extension of or alternative to WAN but this paper limits its discussion to WLAN.

Initially, Computer was manufactured to be a single operating machine but as researches advanced, the issue of networking came into existence. The Engineers later thought of connecting two or more computers together to share resources which gave birth to networking. The Computer Engineers brought in computer network which makes it easier for two or more computers to be connected together and communicate with a view to sharing resources such as printers, telephone lines, fax machine, scanner, drives etc. So, Network is interconnectivity of two or more network devices to share resources. [1] [2]

1.2 Computer Network

Computer network is a connection of two or more computer systems together in order to share resources such as printers, drives, internet, telephone lines, fax machine, applications etc

1.3 Major Categories of Network

Local Area network

This is a connection of two or more computers or workstations within a small geographical area such as home, buildings, closed group of buildings, offices, schools etc.

Metropolitan Area Network

This is a connection of two or more computers or workstations within a metropolis. It could be a connection of two or more LANs within the metropolis. . MAN can be wired, wireless or both like LAN.

Wide Area Network

This is a connection of two or more computers within a large geographical area such as country to country, city to city, state to state etc. e.g. Nigeria to Ghana, and Nigeria to India etc. WAN can be wired, wireless or both Like MAN and LAN.

Other Categories of Network

1. Personal Area Network (PAN)
2. Home Area Network (HAN)
3. Storage Area Network (SAN)
4. Enterprise Private Network (EPN)
5. Virtual Private Network (VPN)
6. Backbone Network (BN)
7. Campus Area Network (CAN)

1.4 Wireless LAN Networking Media/Hardware

Access Point

The access point is a device that links a wireless network to a wired LAN. It increases the effective range of a wireless network and provides additional network management and security features. Wireless networks of three or fewer PCs do not require an access point for ad-hoc networking. Access points are useful for larger networks, and they are particularly well-suited for adding wireless capability to an existing wired network.

Router

A router is a device used for sharing a single Internet connection across multiple computers. This is ideal in the home or office where multiple computers and devices can be online at the same time with only a single Internet connection.

PC Card

A wireless PC card enables laptop users to connect wirelessly to the LAN.

1.5 Objectives of the paper

The main objective of this paper is to equip IT support staff, students, instructors, network users of any establishment, and anybody who is interested in WLAN with the first hand information on wireless LAN, and what it takes to implement a standard wireless LAN environment. Also, it is to enhance learning and teaching on Wireless LAN Networking with a view to providing a conducive environment for teaching, learning and research. This paper will be useful to both students and instructors of computer science who want to know more about wireless LAN because the paper has been prepared to be a source of knowledge for IT managers, Engineers, staff, students and network users, and anyone who is interested in knowing the technologies behind wireless LAN and how it can be used to enhance performance. The readers will not only have ideas of technical issues involved in implementing a standard WLAN, but they will also appreciate the ways in which a wireless LAN can enhance educational process for students, staff and any interested party.

Wireless LAN Technology

Wired LAN is implemented using networking cables to connect two or more computers and other networking devices together to share resources such as internet, printers, telephone, scanner etc. This is achieved by using cables as a networking media; Wireless LAN is easy way of extending or replacing a wired Local Area Network simply called LAN. Wireless LAN enables users to connect wireless devices without using cables. This seminar paper, therefore, focuses on wireless LAN.

1.6 Method of Research

Wireless LAN standard

Technical Standards

Technical standards are one of the main concerns of users of wireless LAN products. Users would like to buy wireless products from different manufacturers and be able to use them on one network. The IEEE Project 802.11 has set up universal standards for wireless LAN. Some of these standards will be considered [7].

Requirements

In March 1992, the IEEE Project 802.11 established a set of requirements for wireless LAN. The minimum bandwidth needed for operations such as file transfer and program loading is 1Mbps. Operations which need real-time data transmission such as digital voice and process control, need support from time bounded services [7].

Types of Wireless LAN

The Project 802.11 committee distinguished between two types of wireless LAN :

“ad-hoc” and “infrastructred” networks [4] [7].

Figure 2 : (a) Infrastructred Wireless LAN; (b) Ad-hoc Wireless LAN. [4] [7]

Ad-hoc Networks

Figure 2b shows an ad-hoc network. This network can be set up by a number of mobile users meeting in a small room. It does not need any support from a wired/wireless backbone. There are two ways to implement this network.

1.7 Broadcasting/Flooding

This aspect explains a situation in which a mobile user A wants to send data to another user B in the same area. When the packets containing the data are ready, user A broadcasts the packets. On receiving the packets, the receiver checks the identification on the packet. If that receiver is not the correct destination, then it rebroadcasts the packets. This process is repeated until user B gets the data. In this method, the mobile users set up a temporary infrastructure. But this method is complicated and it introduces overheads. It is useful only when there is small number of mobile users.

Infrastructure Networks

Figure 2a shows an infrastructure-based network. This type of network allows users to move in a building while they are connected to computer resources. The IEEE Project 802.11 specified the components in a wireless LAN architecture

Temporary Infrastructure

In infrastructure network, a cell is also known as a Basic Service Area (BSA). It contains a number of wireless stations. The size of a BSA depends on the power of the transmitter and receiver units, it also depends on the environment. A number of BSAs are connected to each other and to a distribution system by Access Points (APs). A group of stations belonging to an AP is called a Basic Service Set (BSS). Figure 3 shows the basic architecture for wireless LANs.

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Figure 3 : Architecture for Wireless LANs [4] [6]

WLAN topologies

IEEE 802.11 supports three basic topologies for WLANs [2][3]: the Independent Basic Service Set (IBSS), the Basic Service Set (BSS), and the Extended Service Set (ESS). All three configurations are supported by the MAC layer implementation. The 802.11 standard defines two modes: ad-hoc/IBSS and infrastructure mode. Logically, an ad-hoc configuration is analogous to a peer-to-peer office network in which no single node is required to function as a server [2]. IBSS WLANs include a number of nodes or wireless stations that communicate directly with one another on an ad-hoc, peer-to-peer basis, building a full-mesh or partial-mesh topology. Generally, ad-hoc implementations cover a limited area and are not connected to any larger network.

Using infrastructure mode, the wireless network consists of at least one access point connected to the wired network infrastructure and a set of wireless end stations. This configuration is called a Basic Service Set (BSS). Since most corporate WLANs require access to the wired LAN for services (file servers, printers, Internet links), they will operate in infrastructure mode and rely on an Access Point (AP) that acts as the logical server for a single WLAN cell or channel. Communications between two nodes, A and B, actually flow from node A to the AP and then from the AP to node B. The AP is necessary to perform a bridging function and connect multiple WLAN cells or channels, and to connect WLAN cells to a wired enterprise LAN.

Implementation of a Standard Wireless LAN

This section discusses design and implementation of a standard wireless LAN using Dr. Olagunju Computer centre of Federal Polytechnic Offa as a case study.

List of Equipment with the Cost of Implementation

The Table 1 through 5 below show the list of equipment used in designing Wireless LAN in LAB 1 of Dr. Olagunju Computer Centre, Federal Polytechnic Offa, Kwara State.

REFERENCES