Basics of Computer Networking Information Technology Department Bryar Hassan (BSc & MSc Eng.) bryar.hassan@kissr.edu.krd

Contents Computer Network Benefits of Computer Network Types of Computer Network Based on physical division Based on coverage area Based on topology Computer Network Hardware Types of Communication Media Internet Technology – First Year

Computer Networks Computer Network is a group of computers which are connected on each other Formed to build efficiency and effectiveness Contained by sever and client computers Server is also the gateway for the computer network through internet access Internet Technology – First Year

Benefits Resources sharing High reliability Money saving Communication facilities Internet Technology – First Year

Types of Computer Networks Physically is divided into two: Wired network Wireless Based on coverage area: LAN (Local Area Network) MAN (Metropolitan Area Network) WAN (Wide Area Network) Internet Internet Technology – First Year

Types of Computer Networks (Cont.) Based on topology: Bus topology Star topology Ring topology Mesh topology Hybrid topology Internet Technology – First Year

LAN (Local Area Network) Connecting ten meters inside a building Internet Technology – First Year

MAN (Metropolitan Area Network) It is used to for the connection among some buildings Internet Technology – First Year

WAN (Wide Area Network) Connecting some areas Internet Technology – First Year

LAN Versus WAN Internet Technology – First Year

The Internet Connecting the world globally Internet Technology – First Year

Types of Computer Network Based on topology: the physical layout of a network, i.e. wires and equipment Choices affects Network performance Network size Network collision detection Types: Bus, Star, Ring, Mesh, and Hybrid Internet Technology – First Year

Bus Topology Also called linear bus Advantages Disadvantages Easy to setup Small amount of wire Disadvantages Slow Easy to crash Internet Technology – First Year

Star Topology All nodes are connected to a hub The most common topology Advantages Easy to setup Disadvantages One hub crashing down entire network Uses lots of cable Internet Technology – First Year

Ring Topology Nodes are connected in a circle Advantages Disadvantages Time to send data is known No data collision Disadvantages Slow Lots of cable Internet Technology – First Year

Mesh Topology All computer are connected together Advantages Data will always be delivered Reliable No collision Disadvantages Hard to setup Lots of cable Internet Technology – First Year

Hybrid Topology Internet Technology – First Year

Computer Network Hardware Modem Network Interface Card (NIC) Hub Switch Router Communication media Internet Technology – First Year

Modem Converts digital signal to analogue and vice versa Conversion from digital to analogue called modulation Conversion from analogue to digital called demodulation Measures in bits per second (bps) Internet Technology – First Year

Network Interface Cards (NIC) Ethernet Card/Network Adapters Connects each computer to wiring in the network Handles sending, receiving, and error checking of transmitted data Internet Technology – First Year

Hubs Centres of a star network All nodes receive transmitted packets Slow and insecure Internet Technology – First Year

Switches Replacement for hubs Only intended note receives transmission Fast Secure Keep track of MAC addresses Intelligent device Internet Technology – First Year

Routers Connects two or more LANs, WANs together Packages sent to remote LAN cross Connect internal networks to the Internet Selection of best available path and path forwarding Need configured before installation Internet Technology – First Year

Types of Communication Media Unshielded/Shielded Tw Coaxial cables Fiber optics Internet Technology – First Year

Twisted Pair Cables Two wires twisted around each other to reduce electrical interference Inexpensive Already in place for telephone systems Most common LAN cable and telephone systems Speeds range from 1 Mbps to 1,000 Mbps Internet Technology – First Year

Twisted Pair Cables Unshielded Twisted Pair (UTP) Ordinary telephone wire Cheapest and easiest to install Suffers from interference Shielded Twisted Pair (STP) Metal braid that reduces interference More expensive Harder to handle (thick, heavy) Internet Technology – First Year

Twisted Pair Cables Internet Technology – First Year

Coaxial Cable A center conductor wire surrounded by layer of insulation and metallic sheath Higher bandwidth and has less noise than twisted pair Shielded from interference Speed up to 10 Mbps Television distribution Antenna to TV and cable TV Long distance telephone transmission Internet Technology – First Year

Fibre Optic Used light instead of electricity to send data Much higher bandwidth than coaxial cable Very secure Hard to work with Speeds up to 100 Gbps Internet Technology – First Year

References Slideshare lecture notes, online. Available on: http://www.slideshare.net/ Tanenbaum, Andrew S. Computer networks. Vol. 4. Englewood Cliffs (NY): Prentice-Hall, 1989. Internet Technology – First Year