Computer Network Technology English for ICT

Networking what and why? Networking allows two or more computer systems to exchange information and share resources and peripherals. Thus, computer network helps deduces cost.

Network Classification Networks are classified according to: Geographical area PAN, LAN, MAN, WAN Architecture Server-based, Peer-to-peer Topology Star, Bus, Ring Network protocol TCP/IP, Ethernet, AppleTalk

Geographical Area PAN (Personal Area Network) LAN (Local Area Network) MAN (Metropolitan Area Network) WAN (Wide Area Network)

Network PANs include a laptop, a mobile phone, and a PDA. LANs are usually placed in the same building or within limited distance with each other. MANs are networks with a maximum range of about 75 kilometers (45 miles) or so, and with high-speed transmission capabilities. WANs have no geographical limit and may connect computers or LANs (including MANs) on opposite sides of the world.

Network Architecture In the administrative relationship between nodes, networks can be divided into: Server-based network Peer-to-peer network

Server-Based Network A server controls access to some resource (i.e. harddisk, printer, etc.) Server serves as a host for workstation connected to the server. A workstation requests services, such as access to files or programs on the hard disk or use of a printer, from a server.

Peer-To-Peer Network Computers in the network may have same capabilities. At one point, a given node (node A) may provide services for another node (node B). At another time, node B may provide similar or different services for node A.

Network Topology Topology refers to the sahpe of a network There are three basic physical topologies, including: Star Bus Ring

Star Network

BUS

Ring Network

Mesh Network

More on Physical Topologies

Network Protocols Protocols are the languages or set of rules. Computers use protocols to communicate with each other. Networks use different protocols such as: TCP/IP, Ethernet, AppleTalk

LAN PCs in a LAN are called nodes. Nodes may be servers or workstations. Nodes are connected to a network by means of a network interface card (NIC) Also called a network adapter card.

Network Connections Wired Network Wireless Network Wired Networks are linked by Ethernet cables, phone lines, and high speed fiber optic cables. Wireless Network Wireless networks use electromagnatic waves such as radio waves to transmit data.

Types of Wireless Network Satellites - for long distance (270 msec end-end delay) WiMAX - for connecting WiFi hotspots. WiFi - for medium range distances Bluetooth - for short distances GSM - for mobile phones (cell-phones)

WiMAX (Worldwide Interoperability for Microwave Access)  WiMAX is a wireless communications standard designed to provide 30 to 40 Mbps data rates (up to 1 Gbps) Providing at-home or portable mobile broadband connectivity across cities or countries.  Operating at the maximum range of 50 km (31 mi)

Wireless Network (802.11)

Cat-5 Socket and Cable

Fiber Optic Cable

Hub A hub is a component that serves as a common termination point for multiple nodes and that can relay signals along the appropriate paths. A hub is a box with a number of connectors to which nodes are attached

HUB

HUB

Switch Physically, a switch resembles a hub. It is used to separate LAN segment. It has higher data rate (10/100/1000 Mbps)

Switch

Router A router connects two or more different networks together. It provides a path from a node on one network to a node on another network. If a computer in one network would like to connect to another computer on different network, a router provides a path so that these two computers can communicate with each other.

Router

Wireless Access Point

Wireless Access Point (cont) A combination of Access Point, Switch, and Router

Wireless Access Point (cont) Base station Mobile hosts Router

Network Mediums

Cat-5 Cable

Coaxial Cable and T-Connector

Fiber Optical Cable

Fiber Optic Connection

Video Tele-Conferrencing