Chapter 1 Computer Networks IB 300 Advanced Computer

Chapter 1: Computer Networks IB 300: Advanced Computer Sciences. Professor: Nabil Elmjati

Introduction Computer network Computers connected together Purpose: Exchanging resources and information Just about any kind of information can be sent Examples: Television and radio signals, voice, graphics, handwriting, photographs, movies 3

Basic Networking Concepts Computer network Set of independent computer systems connected by telecommunication links Purpose: Sharing information and resources Nodes, hosts, or end systems Individual computers on a network 4

Basic Networking Concepts Node: A Node is a connection point. In a physical Network, it is an electronic device that is attached to a network and is capable of sending, receiving and forwarding information over a communication channel (Network) Host: Any Computer connected to a network is considered a host.

Communication Links Switched, dial-up telephone line A circuit is temporarily established between the caller and callee Analog medium Requires modem at both ends to transmit information produced by a computer Computer produces digital information 5

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Communication Links (continued) Dial-up phone links Transmission rate: 56, 000 bps (56 Kbps) Broadband Transmission rate: Exceeding 256, 000 bps (256 Kbps) 8

Communication Links (continued) Options for broadband communications Home use Digital subscriber line (DSL) Cable modem Fiber Optics Commercial and office environment Ethernet Fast Ethernet Gigabit Ethernet 9

Transmission Time of an Image at Different Transmission Speeds 10

Communication Links (continued) Wireless data communication Uses radio, microwave, and infrared signals Enables “mobile computing” Types of wireless data communication Wireless local access network Wireless wide-area access network 11

Local Area Networks Local area network (LAN) Connects hardware devices that are in close proximity The owner of the devices is also the owner of the means of communications Common wired LAN topologies Bus Ring Star 12

Figure 1. 4 Some Common LAN Topologies 13

Local Area Networks (continued) Ethernet Most widely used LAN technology Uses the bus topology Two ways to construct an Ethernet LAN Shared cable Hubs: The most widely used technology 14

An Ethernet LAN Implemented Using Shared Cables 15

Figure 7. 6 An Ethernet LAN Implemented Using a Hub 16

Wide Area Networks Wide area networks (WANs) Connect devices that are across town, across the country, or across the ocean Users must purchase telecommunications services from an external provider Dedicated point-to-point lines Most use a store-and-forward, packet-switched technology to deliver messages 17

Typical Structure of a Wide Area Network 18

IP Address What is an IP Address: � An Internet Protocol address (IP address) is a numerical label assigned to each device (e. g. , computer, printer) that is part of a Computer Network. � Example of IP address: 192. 168. 1. 1 � There are two types of IP addresses: Static and Dynamic.

Static vs Dynamic � � Static IP: A fixed IP that is permanently assigned to a host. Dynamic IP: A temporary IP that expires when the host goes offline, and changes the next time the host connects to the network.

How to know your IP address? Local IP Address: By running the CMD command in windows and typing: “ipconfig” in the terminal, then hitting enter. Public IP (given by the ISP): You can either visit a site such as http: //whatismyipaddress. com/ Or access your router to find out the actual IP address.