Lecture 1: Major Networking Concepts: a Review Dr. Najla Al-Nabhan

Lecture Outline Computer Networks: definition, concepts, uses, issues, hardware, software, etc. Networks Classification  Type of Transmission Technology: Point-to-point and Broadcast Networks.  Scale: PAN, LAN, MAN, and WAN. Reference Models  OSI Reference Model  TCP/IP Reference Model Najla Al-Nabhan Spring lecture1:Revision 2

What is a Computer Network? A computer network is a group of interconnected computers. It allows computers to communicate with each other to share resources and information. Two computers are set to be interconnected if they are able to exchange messages between each other. Connection can be through copper wires, fiber optics, microwaves, infrared, satellite, etc. Najla Al-Nabhan Spring lecture1:Revision 3

What is a Computer Network? Definition: A Computer network is a collection of computing devices with the required software and hardware that enable them to communicate and share resources. Najla Al-Nabhan Spring lecture1:Revision An example of network components Protocols, Standards, etc. Modem, PCs, Routers, Switches, Wires, etc. Modem, PCs, Routers, Switches, Wires, etc. 4

Uses of Computer Networks Sharing resource is the main objective of computer network. Resources include: (information, software and hardware) Wide range of networks applications:  Business applications.  Scientific applications  Home applications  Social Applications  Mobile applications Najla Al-Nabhan Spring lecture1:Revision 5

Networks Classification Two Major Taxonomies: 1. Transmission Technology  Broadcast Networks  Point-to-Point Networks 2. Scale  Personal Area Network (PAN)  Local Area Network (LAN)  Metropolitan Area Network (MAN)  Wide Area Network (WAN)  Internet Najla Al-Nabhan Spring lecture1:Revision 6

Point-to-Point Networks Point-to-point links connect individual pairs of machines. To go from the source(sender) to the destination(receiver), messages may visit one or more intermediate machines before it reaches the destination machine. Often multiple routes, of different lengths, are possible, so finding good ones is important in point- to-point networks. Point-to-point transmission with exactly one sender and exactly one receiver is sometimes called unicasting. (1-to-1) Najla Al-Nabhan Spring lecture1:Revision 7

Point-to-Point Networks: Examples Najla Al-Nabhan Spring lecture1:Revision 8

Broadcast Networks A single communication channel is shared by all machines in the network. Short messages (called packets) 1-to-Many communication: A packet is sent by the “source” machine and received by more than one machine; Broadcasting: Sending a packet to all the machines in the network. Multicasting? Sending a packet to a group of machines in the network. Najla Al-Nabhan Spring lecture1:Revision 9

Broadcast Networks: Examples Najla Al-Nabhan Spring lecture1:Revision 10

SCALE(SIZE) BASED NETWORK CLASSIFICATION 1. PAN 2. LAN 3. MAN 4. WAN 5. Internet Najla Al-Nabhan Spring lecture1:Revision 11

Najla Al-Nabhan Spring lecture1:Revision Network size increases 12

Personal Area Network (PAN) computer network organized around an individual person. PAN involves a computer, a cell phone..etc Using Bluetooth and USB often used to link this kind of networks. Communication Technology:  Wired  Wireless (WPAN):(Bluetooth, infrared) Najla Al-Nabhan Spring lecture1:Revision 13

Local Area Network (LAN) A LAN is a privately owned network that operates within and nearby a single building like a home, office or factory. The connection must be high speed and inexpensive. Size: few kilometers. Najla Al-Nabhan Spring lecture1:Revision 14

Local Area Network (LAN) In Wireless LAN, each computer talks to a device, called an AP(Access Point), wireless router, or base station. This device helps in transferring packets between the wireless computers and also between them and the Internet. Najla Al-Nabhan Spring lecture1:Revision Wired LANWireless LAN 15

Local Area Network (LAN) Advantages  Easy to share devices (printers, scanners, external drives)  Easy to share data files (homework, pictures)  Cost of LAN setup is low. Disadvantages  Power: a good LAN is required to be on all the times.  Security: each computer and device become another point of entry for undesirables.  If all computers are running at the same time, the speed might be reduced.  Covers limited area. Najla Al-Nabhan Spring lecture1:Revision 16

Metropolitan Area Network (MAN) A metropolitan area network (MAN) is a high- speed network that connects local area networks in a metropolitan area It covers a city. Examples:  A network that handles the bulk of communication activities across a city or town.  The cable television networks available in many cities. Najla Al-Nabhan Spring lecture1:Revision 17

Metropolitan Area Network (MAN) Najla Al-Nabhan Spring lecture1:Revision A MAN based on cable TV. A MAN covering a university campus, hospital and other. 18

Metropolitan Area Network (MAN) Advantages  Efficiency and shared access.  All the computers residing in the same area have an equal chance to access the network. Disadvantages  It can be costly(hardware, software, support, etc.)  Security problems  As the network consists of many computers over the span of a city, the connection can become quite slow. Najla Al-Nabhan Spring lecture1:Revision 19

Wide Area Network (WAN) A wide area network (WAN) is a network that covers a large geographic area (such as a city, country, or the world) using a communications channel that combines many types of media such as telephone lines, cables, and radio waves. Najla Al-Nabhan Spring lecture1:Revision 20

Wide Area Network (WAN) A wide area network (WAN) is a network that covers a large geographic area (such as a city, country, or the world) using a communications channel that combines many types of media such as telephone lines, cables, and radio waves. Najla Al-Nabhan Spring lecture1:Revision 21

The Internet is the world’s largest WAN. Wide Area Network (WAN) Najla Al-Nabhan Spring lecture1:Revision 22

Wide Area Network (WAN) Advantages  Increased efficiency.  Ease of communication. Disadvantages  Security problems.  Training costs.  Maintenance problems: Large enterprises will dedicate staff to maintain their WAN. Najla Al-Nabhan Spring lecture1:Revision 23

Common Networking Terminologies Wi-Fi (Wireless Fidelity)  A wireless technology that connects computers without cables Access Point (AP)  A device (base station) that connects wireless devices together  Usually connected to a wired-network Hotspot  The area covered by wireless access points Satellite  A broadcast system that provides digital data transmission over satellites Najla Al-Nabhan Spring lecture1:Revision 24

Intranet vs. Internet Intranet  A private network that is contained within an enterprise  Could be LANs and WANs Internet  A public network of networks (a WAN) Both are using TCP/IP Najla Al-Nabhan Spring lecture1:Revision 25