Computer Networks Lvl_3_ Lec 1 & 2 PDF

Computer Networks Introduction Dr. Amr A. Alammari Lecture (1&2) Computer Networks Grading Policy ▪ Mid Exam (15 Marks) - No make-up exam ▪ Final Exam (40 Marks) ▪ Quizzes (5 Marks) - No make-up quizze...

Computer Networks Introduction Dr. Amr A. Alammari Lecture (1&2) Computer Networks Grading Policy ▪ Mid Exam (15 Marks) - No make-up exam ▪ Final Exam (40 Marks) ▪ Quizzes (5 Marks) - No make-up quizzes ▪ Attendance (5 Marks) - Penalty for late attendance ▪ Assignments (5 Marks) - Absence is not an excuse for not submitting homework assignments. - Late assignments will not be accepted. Computer Networks- Objectives Course Objectives The objective of this course is to provide students with a comprehensive understanding of computer networks and their underlying technologies. By studying network classifications, configurations, protocols, and transmission techniques, students will develop the skills to analyze network system requirements, design network systems, and effectively transmit and exchange information within a network. Textbooks ▪ Data Communications and Networking Behrouz Forouzan. Introduction Introduction to Computer Networks and Data Communication Introduction Telecommunication ▪ When we communicate, we are sharing information. This sharing can be local or remote. ▪ The term Telecommunication, which includes, telephony, telegraphy, and television, means communication at a distance using electrical signals or electromagnetic waves. Network and Communication ▪ Network and Communication refer to the interconnected systems and devices that enable the transfer of data and information between various endpoints. Introduction DATA COMMUNICATIONS ▪ Data communications are the exchange of data between two devices via some form of transmission media. Information today comes in different forms such as: - Textual Information (books, reports, emails, messages, etc.) - Multimedia Content (combination of different media types, such as images, videos, audio recordings, and animations) - Numeric Data (statistics, measurements, financial data) - Visual Representations (charts, diagrams, infographics) - Real-time Data (live feeds, streaming data, social media updates) Introduction Networks ▪ A network refers to the interconnection of a group of devices that can communicate with each other. ▪ These devices, (such as computers, servers, routers, switches, and other network-enabled devices), are connected using various wired or wireless technologies to enable the exchange of data, resources, and services. ▪ The network infrastructure facilitates communication and collaboration among the connected devices, allowing them to share information and work together efficiently. Introduction Telecommunication Networks Telecommunication Networks What is a Telecommunication System ▪ A telecommunication system is a collection of nodes and links to enable telecommunication. - The nodes in the system are the devices we use to communicate with, such as a telephone or a computer. - E-mail, phone calls, text messaging, viewing pages on the internet, downloading files, all of these communications make use of a telecommunication system. ▪ Examples of telecommunications systems: - Telephone Dr. Amr network, A. Alammari - Radio broadcasting system, Lecture (4) - Computer networks, -18/07/2023 Internet. 02/03/2023 Telecommunication Networks Components of a Telecommunication System ▪ In its most fundamental form, a telecommunication system includes: - A transmitter to take information and convert it to a signal. - A transmission medium to carry the signal. - A receiver to take the signal and convert it back into usable information ▪ This applies to any communication system, whether it uses computers or not. ▪ Modern telecommunications systems can transmit video, voice, graphic images, Dr. Amr and text A. Alammari information. Lecture (4) ▪ The components required to transmit information include computers to process 18/07/2023 information, terminals to send and receive data, processors, and software. 02/03/2023 Telecommunication Networks Telecommunication Network ▪ Most modern-day telecommunications systems are best described in terms of a network. - Telecommunications systems involve the transmission of information over long distances, and networks are the infrastructure that allows this communication to occur. - Whether it's the internet, mobile networks, voice over IP (VoIP) systems, or other telecommunications technologies, they all rely on networks to connect devices and facilitate the exchange of data and communication. ▪ Networks provide the backbone for these systems, enabling efficient and reliable communication across various devices and locations. ▪ There are six basic components to a telecommunications network: Input and output devices; Telecommunication channels; Telecommunication Processors; Control Software; Messages; and Protocols. 02/03/2023 Telecommunication Networks Components of a Telecommunication Network ▪ Input and Output Devices - Also referred to as ‘terminals’: These provide the starting and stopping points of all communication. - A telephone is an example of a terminal. In computer networks, these devices are commonly referred to as 'nodes' and consist of computer and peripheral devices. 02/03/2023 Telecommunication Networks Components of a Telecommunication Network ▪ Telecommunication Channels - The medium for transmitting and receiving data. - This includes various types of cables and wireless radio frequencies. 02/03/2023 Telecommunication Networks Components of a Telecommunication Network ▪ Telecommunication processors - Which provides a number of control and support functions: For example, in many systems, data needs to be converted from analog to digital and back. ▪ Control Software - Which is responsible for controlling the functionality and activities of the network. - It provides tools and features to manage network devices, monitor network performance, configure network settings, and troubleshoot network issues. 02/03/2023 Telecommunication Networks Components of a Telecommunication Network ▪ Messages - This represents the actual data being transferred between devices or systems in a network. - Messages serve as containers for the data. - The content and format of messages depend on the specific application, protocol, or system involved in the communication. ▪ Protocols - This specifies how each type of telecommunication system handles the messages. It specifies how devices or systems should exchange information, interpret the data, and ensure reliable communication. For example, GSM and 3G are protocols for mobile phone communications and TCP/IP is a protocol for communications over the Internet. 02/03/2023 Introduction Examples of Telecommunication Systems: Telephone Network Telephone Network Definition ▪ A telephone network is a telecommunications system that allows users to make voice calls to other users over long distances. - Telephone networks use a combination of wired and wireless technologies to transmit voice signals between users. ▪ The basic components of a telephone network include, Telephones, Local Exchange, Trunk Lines, Switching Centers, and Public Switched Telephone Network (PSTN). - Telephones are devices that allow users to make and receive voice calls over the telephone network. - Telephones can be either wired or wireless and can be used to make calls within a local area or to other users in distant locations. 02/03/2023 Telephone Network Basic Components ▪ The basic components of a telephone network include Telephones, Local Exchange, Trunk Lines, Switching Centers, and Public Switched Telephone Network (PSTN). - Local Exchange, also known as a central office or exchange, is a facility that connects telephones within a local area. - Local exchanges are responsible for routing calls to their intended destination. - The local exchange typically consists of a building or set Dr.ofAmr buildings that house a variety of equipment A. Alammari and personnel, including switching Equipment, Local Exchange Telephone Lines, Lecture (4) Network Operations Centers, and Customer Service Centers. 18/07/2023 02/03/2023 Telephone Network Basic Components ▪ The basic components of a telephone network include Telephones, Local Exchange, Trunk Lines, Switching Centers, and Public Switched Telephone Network (PSTN). - Trunk Lines are high-capacity telephone lines that connect local exchanges to each other and to long-distance carriers. - Trunk lines are used to transmit voice signals over long distances. - Long-distance carriers are companies that provide Dr. Amrtelephone services between distant A. Alammari locations. Long-distance carriers use trunk lines toLecture transmit (4) voice signals between local exchanges. 18/07/2023 - 02/03/2023 Telephone Service in a Large Area Telephone Network Basic Components ▪ The basic components of a telephone network include Telephones, Local Exchange, Trunk Lines, Switching Centers, and Public Switched Telephone Network (PSTN). - Switching Centers are facilities that connect multiple local exchanges and long-distance carriers. Switching centers are responsible for routing calls between different telephone networks. Dr. Amr A. Alammari Lecture (4) 18/07/2023 02/03/2023 Telephone Network Basic Components ▪ The basic components of a telephone network include Telephones, Local Exchange, Trunk Lines, Switching Centers, and Public Switched Telephone Network (PSTN). - Public Switched Telephone Network (PSTN), Also known as Landlines, Plain Old Telephone Service (POTS), or fixed-Line Telephones, is the global network of interconnected telephone networks that allows users to make voice calls to other users around the world. - The PSTN consists of switches at centralized points on the networks. These switches act as nodes for communication between two points on the network. 02/03/2023 Telephone Network Other Forms of Telephone Networks ▪ Other forms of telephone networks include, Mobile Cellular Network, Cable TV networks. - Mobile Cellular Network: a two- way radio link is used to connect the mobile handset to its exchange, rather than a copper pair of wires, so that the user has freedom of movement. - Serving exchange must have a system to identify a calling handset and another system to keep track of where a particular handset is at any time, so that it can send or receive calls - The basis of the ‘access network’ is a set of cells. 02/03/2023 Telephone Network Other Forms of Telephone Networks ▪ Other forms of telephone networks include, Mobile Cellular Network, Cable TV networks. - Cable TV Network: (also known as often Cable Networks, are primarily based on a cable-distribution system, deployed in certain areas of a town, which delivers many TV broadcast channels to the residential market. - The TV channels are provided from the TV source, known as the head end, which may receive the TV channels from a satellite or other terrestrial links to TV broadcast companies and possibly a TV channel switching and control center. 02/03/2023 Introduction Examples of Telecommunication Systems: Computer Network Computer Network Definition ▪ A computer network is a system of computers and peripheral devices that are connected electronically. - These connected computers can communicate with each other, which means that they can share information. - Each computer has its own network address, so it can be uniquely identified among all the computers in a network. - Computer networks are able to carry different types of data and support different applications. ▪ Computers are connected using a number of different types of communication channels. These include both wired and wireless connections. Dr. Amr A. Alammari - Wired connections consist of an actual physical cable, such as copper wire or fiber optics. Lecture (4) - Wireless connections do not use a physical cable but transfer data using waves at a 18/07/2023 particular part of the electromagnetic spectrum. 02/03/2023 Computer Network Why do we need a computer network? - Transferring files between individual computers can be accomplished using physical media, such as DVDs or external hard drives, but a computer network provides several advantages over using physical media for transferring files between individual computers. ▪ Some of the advantages of computer networks are: - File sharing - Internet connection sharing - Sharing of peripheral devices Dr. Amr A. Alammari - Increased storage capacity ▪ The network Lecture (4) itself can also carry out tasks that are difficult for any single computer to do. These18/07/2023 network services have become increasingly important as many different types of devices are connected to each other. 02/03/2023 Computer Network Types of computer networks ▪ There are different ways to describe computer networks, including network size, transmission media, management method, and network topology. - Network Size, relates to the geographic area occupied by the computers and the network and the behavior of the computers when data is shared. For example: - Local Area Network, or LAN: consists of a computer network at a single site, typically an individual building. Dr. Amr A. Alammari - Wide Area Network, or WAN: occupies a very Lecture large (4)such as an entire country or the area, entire world. The Internet is the best-known 18/07/2023 example of a WAN. 02/03/2023 Computer Network Types of computer networks ▪ There are different ways to describe computer networks, including network size, transmission media, management method, and network topology. - Transmission Media, describes the material substances that carry energy waves, which include the data being transferred. The two main categories are wired connections and wireless connections. - Wired Connection: uses physical cables, such as twisted- pair cables, coaxial cables, and fiber optic. Dr. Amr A. Alammari - Wireless Connection, there is no any physical media Lecture (4) between the transmitter and the receiver. 18/07/2023 02/03/2023 Computer Network Types of computer networks ▪ There are different ways to describe computer networks, including network size, transmission media, management method, and network topology. - Management Method, refers to the way in which the network is administered and controlled. There are several management methods for computer networks, including centralized management, decentralized management, and distributed management. - Centralized Management, One central server controls and manages all network resources - Decentralized Management, involves distributing management tasks across multiple administrators or devices within the network. - Distributed Management, No central server, management is distributed across multiple nodes. 02/03/2023 Computer Network Types of computer networks ▪ There are different ways to describe computer networks, including network size, transmission media, management method, and network topology. - Network Topology, refers to the physical or logical arrangement of devices and links in a computer network. There are several types of network topologies, including: - Bus Topology: all devices are connected to a single cable, called a bus. - Star Topology: each device is connected directly to a central hub or switch. - Ring Topology: devices are connected in a circular chain, with each device connected to the two devices adjacent to it. - Mesh Topology: each device is connected to every other device in the network. - Hybrid Topology: multiple topologies are combined to create a more complex network architecture. Hybrid 02/03/2023 Computer Network Network Properties ▪ A computer network can also be described in terms of its properties. These include bandwidth, cost, and reliability. - Bandwidth, is the amount of data that can be transferred over a network per second. - Bandwidth is also referred to as 'data transfer rate' or 'capacity' and is typically expressed in megabits per second (Mbit/s or Mbps) or gigabits per second (Gbit/s or Gbps). For example: - The bandwidth of a typical wireless network using Wi-Fi is between 11 and 54 Mbit/s, while the bandwidth of a typical wired Ethernet connection is 1 Gbit/s or more. 02/03/2023 Computer Network Network Properties ▪ A computer network can also be described in terms of its properties. These include bandwidth, cost, and reliability. - Cost, which can be broken down into the cost of installing the network hardware, such as cables and switches, and the cost of running and maintaining the system. - Reliability, refers to how often the network does not perform as expected. - Just like a regular desktop computer, a computer server can crash and stop working. - More reliable networks have backup systems in place so that if one server were to fail, another one takes over. 02/03/2023 Introduction Examples of Telecommunication Systems: Internet Internet The Concept of the Internet ▪ The Internet, that widely-known entity, is a super constellation of many networks around the world – a network of networks. - Each of these networks is based on a special form of switching designed specifically for handling data, using a standard way of packaging and addressing the data: the so-called Internet protocol (IP). - The introduction of the World Wide Web (WWW), which enabled widespread access to specific sections (referred to as 'pages') of data stored on people's computers, caused the Internet to spread across the world and become the phenomenon it is today. ▪ A huge range of applications by business and residential users now exploits the Internet. Dr. Amr A. Alammari - The most common of these applications are e-mails and other peer-to-peer applications such as Lecture (4) gaming, information gathering from web pages, and Internet shopping. 18/07/2023 02/03/2023 Internet Internet service providers ▪ Each of the components in the Internet constellation is owned and operated by Internet service providers (ISPs). - Users and providers of information (in the form of web pages) subscribe to an ISP for their Internet service. Users access their ISPs over links provided by one of a range of networks (PSTN, ISDN, mobile, leased line, ADSL/broadband, and Cable TV). - ISP networks usually comprise a number of IP switching units (known as ‘routers’) located at various points in the country and linked by high-capacity transmission circuits leased from a network operator (PSTN), so-called leased lines, or private circuits. - ISP networks link with one another in order to obtain full interconnectivity between users, the Dr. smaller Amr A.onesAlammari connect to larger ISPs, who in turn connect to the largest ISPs, those with national or Lecture international (4) coverage – the ‘backbone ISPs’. 18/07/2023 02/03/2023 Internet A simplified schematic diagram of the Internet Dr. Amr A. Alammari Lecture (4) 18/07/2023 02/03/2023 Internet How subscribers gain access to Internet? ▪ There are different ways to get access to the internet, including Dial-up, ISDN, DSL, Cable Service, and other Internet Connection Types. - Dial-up, The original and still common way of accessing the Internet is through a telephone call. - A Dial-Up Connection is a Limited time-duration connection that uses the public switched telephone network (PSTN) to connect to the internet. - The procedure is in two stages: the first is a telephony call to the ISP; the second stage is a data transfer session between the computer and the Internet via the ISP. Digital Signal Analog Signal - Connection between the computer and the ISP with the help of a modem. - Modem= modulator/demodulator. 02/03/2023 Internet Dial-up Connection Internet - Analog lines with limited frequency response. - Dial-up is slower than other types of internet connections (56 kbit/s). - User can not use the internet and telephone at the same time. ISP Telephone Lines Modem 02/03/2023 Internet How subscribers gain access to Internet? ▪ There are different ways to get access to the internet, including, Dial-up, ISDN, DSL, Cable Service, and other Internet Connection Types. - ISDN, Accessing the Internet via ISDN (Integrated Services Digital Network) is essentially the same as for the PSTN, except that the interface of the ISDN line to the computer is digital. ISDN Modem Telephone Line Analog Phone - The modem card does not convert the computer output to analog. Client A 02/03/2023 Internet ISDN Connection - The ISP is connected to the PSTN over a standard local line or by an ISDN local line. - Higher speeds up to 128 kbit/s are possible. 02/03/2023 Internet How subscribers gain access to Internet? ▪ There are different ways to get access to the internet, including Dial-up, ISDN, DSL, Cable Service, and other Internet Connection Types. - DSL, (digital subscriber line) is an effective way of avoiding overloading the PSTN by the total segregation of telephony and Internet. - This provide users with a high- speed Internet access by routing their data traffic to the ISP independently of the PSTN. - The use of ADSL enables a high- speed data service to be carried in addition to telephony over the copper pair of a standard telephone line. 02/03/2023 Internet DSL Connection - High data transmission internet (broadband connection) which allows us to watch and download videos and share huge files easily. - Work on internet and make calls at the same time. The data stream carrying the Internet- bound traffic is connected to the DSLAM (digital subscriber line access multiplexor) equipment, which combines the data from many such lines onto a high speed transmission link to a data network. 02/03/2023 Internet How subscribers gain access to Internet? ▪ There are different ways to get access to the internet, including Dial-up, ISDN, DSL, Cable Service, and other Internet Connection Types. - Cable Modem: Cable TV networks are able to provide a high-speed data link to an ISP over one of the spare TV channels carried through the network. - The technique requires a so-called cable modem, which converts the output of the computer into a signal compatible with the TV distribution system. 02/03/2023 Internet Cable Service Connection - High-speed broadband connection with the same infrastructure as cable television. - As with ADSL, the Cable TV operator routes the aggregated data traffic over a data network to the connecting points of the appropriate ISPs 02/03/2023 Internet How subscribers gain access to Internet? ▪ There are different ways to get access to the internet, including Dial-up, ISDN, DSL, Cable Service, and other Internet Connection Types. - Fiber Connection, Delivered by fiber optic cables. Fiber internet broadband can deliver significantly faster internet speeds than traditional cable or DSL. - It’s also more reliable than other types of internet connections: Unlike copper wire cables, fiber optic cables won’t get distorted when transmitting data over long distances. 02/03/2023 Internet How subscribers gain access to Internet? ▪ There are different ways to get access to the internet, including Dial-up, ISDN, DSL, Cable Service, and other Internet Connection Types. - Wireless Connection, Wireless broadband connects a home or business to the Internet using a radio link between the customer’s location and the service provider’s facility. - There are several methods of wireless internet access, including, Wi-Fi, Cellular Data, Fixed Wireless Internet, and WiMAX. 02/03/2023 Internet How subscribers gain access to Internet? ▪ There are different ways to get access to the internet, including Dial-up, ISDN, DSL, Cable Service, and other internet Connection Types. - Satellite Connection, A type of wireless internet that uses a dish to receive a satellite signal. - Although it cannot compete with connection types like fiber when it comes to speed and reliability, satellite remains a great option for anyone who lives in a rural area or place otherwise disconnected from physical cable lines. 02/03/2023