Computer Networks Lecture 1 PDF

CS313 Computer Networks Dr. Heba Sabry McGraw-Hill 1  CHAPTER 01 Introduction Data Communications and Networking, With TCP/IP protocol suite Sixth Edition Behrouz A. Forouzan...

CS313 Computer Networks Dr. Heba Sabry McGraw-Hill 1  CHAPTER 01 Introduction Data Communications and Networking, With TCP/IP protocol suite Sixth Edition Behrouz A. Forouzan © 2022 McGraw Hill, LLC. All rights reserved. Authorized only for instructor use in the classroom. McGraw-Hill No reproduction or further distribution permitted without the prior written consent of McGraw Hill, LLC.  CHAPTER 1-PART 1: OUTLINE 1.1 DATA COMMUNICATIONS 1.2 NETWORKS 1.3 NETWORK TYPES McGraw-Hill 3  DATA COMMUNICATIONS The exchange of Information between two devices through a transmission medium McGraw-Hill  COMPUTER NETWORK A computer network: is a group of computers/devices(Nodes) that use a set of common communication protocols over digital interconnections for the purpose of sharing resources located on or provided by the network nodes. McGraw-Hill  NETWORK ELEMENTS ▶ Nodes ▶ Medium ▶ Protocol ▶ Operating System (OS) ▶ Software (SW) McGraw-Hill  NETWORK ELEMENTS Nodes The nodes of a computer network may include personal computers, servers, networking hardware, or other specialized or general-purpose hosts. Medium The interconnections between nodes are formed from a broad spectrum of telecommunication network technologies, based on physically wired, optical, and wireless technologies. Protocol A communication protocol is a set of rules for exchanging information over a network. physically wired, optical, and wireless McGraw-Hill  NETWORK ELEMENTS Network Software (SW) Computers need network software to issue the requests and responses that let them take the roles of client and servers. is used to provide remote access to systems and exchange files and messages in text, audio and/or video formats between different computers or users. Network Operating System is an operating system that manages network resources: essentially, an operating system that includes special functions for connecting computers and devices into a local area network (LAN). The NOS manages multiple requests (inputs) concurrently and provides the security necessary in a multiuser environment. McGraw-Hill  MESSAGE Information today comes in different forms such as text, numbers, images, audio, and video. Text is represented as a bit pattern using Unicode. Numbers are represented in binary. Images are represented as bit patterns Audio refers to the recording or broadcasting of sound or music. Video is a series of images displayed in rapid succession. McGraw-Hill 9  NETWORKS A network is a set of devices (called nodes) connected by communication links. Node can be host (a computer, printer, cell phone) or networking devices (routers, switches, modem, etc) Link is a communication pathway that transfer data from one device to another. A Link can be wired or wireless Type of network connections Point-to-Point: dedicated link between two devices Multipoint : shared link between more than two devices McGraw-Hill  Figure 1.5 Point-to-point connection McGraw-Hill  Figure 1.6 Multipoint connection (shared) McGraw-Hill  Figure 1.2: Data flow Keyboard link – Monitor Link – TV – Radio stations Walkie-Talkie Telephone 1.13  Figure 1.7 Categories of topology Topology: The way in which a network is physically built or The way in which devices interconnect across the network McGraw-Hill  Figure 1.8 Fully connected mesh topology (for five devices) McGraw-Hill  Figure 1.9 Star topology ▪ Dedicated point-to-point link to a central controller only ▪ Number of links = N ▪Advantages ▪ Less expensive than mesh ▪ Easy to install ▪ Easy to add and remove devices ▪ Robust ▪Easy to discover faulty links ▪ Disadvantages? ▪ If the central device failed the whole network will not function McGraw-Hill  Figure 1.10 Bus topology ▪ Number of links = 1 Main + N droplines ▪Advantages ▪ Easy to install ▪ less cabling than mesh and hub ▪ Disadvantages? ▪ Difficult to isolate fault ▪ Difficult to add new devices ▪ A break in the bus cable stops McGraw-Hill all transmission  Figure 1.11 Ring topology ▪ Dedicated point-to-point link between a node and the two nodes on either side of it ▪Number of links = N ▪Advantages ▪ Easy to install ▪ less cable ▪ Easy to add or remove a device ▪ Fault isolation is easy ▪ Disadvantage? McGraw-Hill ▪Not robust  Figure 1.9 A hybrid topology: a star backbone with three bus networks Star - Bus Star - Ring McGraw-Hill  Figure 1.12 Categories of networks McGraw-Hill  2. LOCAL AREA NETWORK Spans a small geographic area such as a home, school, office building, or campus. Usually administered by a single organization or individual. Provides high speed bandwidth to end and intermediary devices within the network. High throughput is the rate of successful message delivery over a communication channel.(productivity) An upside of a LAN is fast data transfer with data speed that can reach up to 10Gbps. Other significant LAN technologies are Fiber Distributed Data Interface (FDDI) and token ring. McGraw-Hill  FIGURE 1.8 AN ISOLATED LAN IN THE PAST AND TODAY McGraw-Hill 22  Figure 1.13 LAN (Continued) McGraw-Hill  4. METROPOLITAN AREA NETWORK 1. A MAN is larger than a LAN but smaller than or equal in size to a WAN. 2. The size range anywhere from 5 to 50km in diameter. 3. MANs are typically owned and managed by a single entity. 4. This could be an ISP or telecommunications company that sells its services to end-users in that metropolitan area. 5. For all intents and purposes, a MAN has the same characteristics as a WAN with distance constraints. McGraw-Hill  Figure 1.14 MAN McGraw-Hill  5. WIDE AREA NETWORK A Wide Area Network exist over a large area Data travels through telephone or cable lines Usually requires a Modem The world’s largest Wide Area Network in the Internet McGraw-Hill  Figure 1.9: A Point-to-Point WAN 1.27  FIGURE 1.11 AN INTERNETWORK MADE OF TWO LANS AND ONE WAN McGraw-Hill Access the text alternative for slide images. 28  FIGURE 1.12 A HETEROGENEOUS NETWORK MADE OF WANS AND LANS 29 McGraw-Hill  THANK YOU 30 McGraw-Hill ©The McGraw-Hill Companies, Inc., 2000