Chapter 1 : Computer Networks. Lecture 2

Computer Networks Classification: 1- Depend on the geographical area. 2- Depend on functional relationship. 3- Depend on Network topology.

1- Depend on the geographical area. 1- Personal Area Network (PAN). 2- Local Area Network (LAN). 3- Metropolitan Area Network (MAN). 4- Wide Area Network (WAN).

1- Personal Area Network (PAN): - A personal area network (PAN) is a computer network that used for communication among computer and different information technological devices close to one person. - Examples of devices that are used in a PAN: personal computers, printers, fax machines, scanners, video game consoles.

1- Personal Area Network (PAN): - PAN may include wired devices (constructed with USB connections) and wireless devices (constructed with Bluetooth). - PAN typically extends to 10 meters.

2- Local Area Networks (LAN). - A LAN is a group of computers, printers and other interconnected devices located in a single room, several rooms within a building or several buildings of a campus. - IEEE (Institute for Electrical and Electronics Engineers) qualifies LAN length as 10 km or less in radius.

2- Local Area Networks (LAN). - Characteristics of a LAN include: Limited geographic operation. High speed data transfer rates. Generally lower in cost than a WAN. Cabling is primary transmission medium.

2- Local Area Networks (LAN).

3- Metropolitan Area Network (MAN). - MAN (Metropolitan Area Network) is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network (WAN). - It covers large geographic areas, such as city.

3- Metropolitan Area Network (MAN)

4- Wide Area Network (WAN). - Wide Area Networks (WANs) extend beyond the LAN to connect networks located in different cities, states, and countries together. - WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations.

4- Wide Area Network(WAN) The Internet is an example of WAN. The Internet : is a global system of interconnected computer networks that used to exchange information using (TCP/IP) protocol.

4- Wide Area Network (WAN).

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2- Depend on functional relationship. 1- Peer-to-Peer Network. 2- Client/Server Network.

1- Peer-to-Peer Network: - A peer-to-peer network consists of a group of computers, each one can act as both client and server. - Great for small, simple, and inexpensive networks. - In a strict peer-to-peer networking setup, every computer is an equal, a peer in the network. - Each computer can have resources (such as files and printers) that are shared with any other computer.

1- Peer-to-Peer Network: - The P2P networks are connected with a simple and visible cabling system. The users can then administer their own computers and the resources they want to share on the network. - Examples of P2P OS are : Windows 95,Windows for Workgroups and Windows NT Workstation.

Peer-to peer network (cont..)

2- Client/Server Network : Client and Server computer role in networking: - Server computer : is a core component of the network, providing a link to the resources necessary to perform any task. - Client computers normally request and receive information over the network depends on the server.

2- Client/Server Network : - A client/server network consists of a group of PCs (called clients), that send the requests to the server. - The server’s function on the network is to service these requests. - The server often has a faster CPU, more memory, and more disk space than a typical client. - Example of client/server-based network is Windows NT Server.

2- Client/Server Network : The types of servers: 1- File server : - It serves the users to share computer programs and data. - It should have hard disk capacity, large memory, and a powerful processor so they can handle the needs of many users. 2- A database server : - It is a computer that stores a database on disk and makes the data accessible by multiple users.

2 -Client/Server Network : 3- Mail Server : - Mail servers provide , chat …etc services to the users. 4- A print server : - It is a device that connects printers to client computers over a network. It accepts print jobs from the computers and send the jobs to the appropriate printers. 5- Internet Information Server/web server : - A web server provides the workstation users access to the Internet web site of the company or organization. This web site if registered can be accessed by Internet.

Client/Server Networking (cont..)