ITGS Syllabus

Thursday, February 16, 2006

Topic 32

Key Terms by Chirag Garg

LAN, WAN, client, server, Ethernet, access, access permissions, login, password, firewall, sysadmin, UPS, EDI


It is a computer network covering a local area, like a home, office, or group of buildings. Current LANs are most likely to be based on switched IEEE 802.3 Ethernet running at 10, 100 or 1,000 Mbit/s or on Wi-Fi technology. The defining characteristics of LANs in contrast to WANs (wide area networks) are: their much higher data rates; smaller geographic range; and they do not require leased telecommunication lines. Thus, some of the issues with LAN are that they have a small geographic range, and as there are numerous systems connected to one, there are more chances of getting them infected my viruses and hackers etc.


A Wide Area Network is a computer network covering a broad geographical area. Contrast with personal area networks (PANs), local area networks (LANs) or metropolitan area networks (MANs) that are usually limited to a room, building or campus respectively. The largest and most well-known example of a WAN is the Internet. WANs are used to connect local area networks (LANs) together, so that users and computers in one location can communicate with users and computers in other locations. Many WANs are built for one particular organization and are private. The different types of WAN’s are Leased Line, Circuit switching, Packet switching, and Cell relay. These different types of WAN’s have problems like call setup, expenses, fixed amount of the transfer of data etc.


A client is a computer system that accesses a (remote) service on another computer by some kind of network. The term was first applied to devices that were not capable of running their own stand-alone programs, but could interact with remote computers via a network. These dumb terminals were clients of the time-sharing mainframe computer.

The client-server model is still used today on the Internet, where a user may connect to a service operating on a remote system through the internet protocol suite. Web browsers are clients that connect to web servers and retrieve web pages for display. Most people use e-mail clients to retrieve their e-mail from their internet service provider's mail storage servers. There are basically three types of clients, the Fat Client, the Thin Client and the hybrid Client. Thus, the fat client gives a high performance and support but have low manageability and flexibility. The thin clients give high manageability and flexibility but don’t have a high performance and support.

The hybrid clients have all the above features of the fat and the thin clients.


In information technology, a server is a computer system that provides services to other computing systems—called clients—over a network. The term server can refer to hardware (such as a Sun computer system) or software (such as an RDBMS server). Although servers can be built from commodity computer components—particularly for low-load and/or non-critical applications—dedicated, high-load, mission-critical servers use specialized hardware that is optimized for the needs of servers. For example, servers may incorporate “industrial-strength” mechanical components such as disk drives and fans that provide very high reliability and performance at a correspondingly high price.


Ethernet is a large and diverse family of frame-based computer networking technologies for local area networks (LANs). The name comes from the physical concept of the ether. It defines a number of wiring and signaling standards for the physical layer, two means of network access at the Media Access Control (MAC)/Data Link Layer, and a common addressing format. Despite the huge changes in Ethernet from a thick coaxial cable bus running at 10 Mbit/s to point-to-point links running at 1 Gbit/s and beyond, all generations of Ethernet (excluding very early experimental versions) share the same frame formats (and hence the same interface for higher layers) and can be readily (and in most cases cheaply) interconnected. Due to the ubiquity of Ethernet, the ever-decreasing cost of the hardware needed to support it and the reduced panel space needed by twisted pair Ethernet, most manufacturers now build the functionality of an Ethernet card directly into PC motherboards, removing the need for installation of a separate network card.

Login & Password

A login is the process of receiving access to a computer system by identification of the user in order to obtain credentials to permit access. It is an integral part of computer security procedure. A username is used in preference to the full name of the user this is a shorter sequence of characters which still uniquely identifies the person. A password is another sequence of characters which provides the user with a key to the system and is kept secret from others. The issues with logins and passwords are that there is a chance of other people trying to get the login and passwords and misuse it. Thus, people usually keep the passwords complicated or personal due to which they are hard to remember and which is why people have a chance of loosing them.

Types of Intrusion

Different types of intrusions are like Viruses, hacking etc. A computer virus is a self-replicating computer program written to alter the way a computer operates, without the permission or knowledge of the user. Though the term is commonly used to refer to a range of malware, a true virus must replicate itself, and must execute itself. The latter criteria are often met by a virus which replaces existing executable files with a virus-infected copy. While viruses can be intentionally destructive—destroying data, for example—some viruses are benign or merely annoying. A hacker is someone who creates and modifies computer software and computer hardware, including computer programming, administration, and security-related items. The term usually bears strong connotations, but may be either favorable or denigrating depending on cultural context.


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