This document provides an overview and introduction to data communications and networking. It discusses why communications are studied, a brief history of communications technologies, and common communication applications. It also introduces key networking concepts like protocols, reference models, networking topologies, and the OSI and TCP/IP protocol stacks. The document concludes by discussing future directions in data transmission and additional reading materials.
This document provides an introduction to data communications and networking. It discusses the history of communications technologies from the telegraph to the internet. It then describes common communication models including the OSI 7-layer model and TCP/IP protocol stack. Key topics covered include data transmission, networking, protocols, standards, and the physical, data link, network, transport, and application layers. The document aims to explain why we study communications and provide context around important concepts, models, protocols and the development of the internet.
Modue 1 part 1 of computer networks for your university examsvish21ainds
A computer network (CN) is a group of devices that share resources over a network, with each device represented as a network node. The devices communicate with each other using standard protocols to send or receive data.
Computers on a network can be linked through cables, radio waves, telephone lines, infrared light beams, or satellites. The network can also include other devices that help in communication, known as network devices.
Here are some types of computer networks:
PAN (Personal Area Network): The smallest and simplest type of network
LAN (Local Area Network): The most frequently used network, connecting computers within a limited area, such as a single office or building
MAN (Metropolitan Area Network): A type of network
WAN (Wide Area Network): An enterprise network spanning cities, buildings, and even countries
Wireless networking is about creating and managing wireless connections, commonly used in Wi-Fi. This involves setting up Wi-Fi routers, securing them with passwords, and allowing devices to connect to a network without using physical cables.
A network connects computers together to share resources. It has physical components like cables and wireless media, and logical components to transport data across the physical layer. Common network topologies include star, bus, ring and mesh configurations. Switches and routers are key devices that intelligently direct traffic in a network. Ethernet is a widely-used networking standard that supports various cabling types and speeds up to gigabit connections.
The document discusses network standards and models including:
- Network communication involves recognizing data, dividing it into chunks, and adding information to determine source/destination and for error checking before sending.
- Standards are needed for hardware/software from different vendors to communicate through standard protocols that control tasks like these.
- There are formal standards developed by standards bodies and de facto standards that emerge in the marketplace.
- Key networking standards organizations that develop standards through specification, identification of solutions, and acceptance processes are ANSI, IEEE, ISO, and ITU.
The document discusses various network models including peer-to-peer networks where computers operate as equals, client-server networks where some computers provide services to others, and hybrid networks that combine aspects of different models. It also describes two-tier and three-tier client-server architectures, with three-tier adding an application server layer to improve efficiency and security over the two-tier approach. Finally, it introduces network reference models like OSI and TCP/IP that define standards for network communication.
The document provides an overview of the history and development of the Internet. It discusses how the Internet began as a US military network called ARPAnet in 1969 and expanded throughout the 1970s. While initially used by researchers and the military, the creation of the World Wide Web in the early 1990s led to widespread commercial and public use of the Internet with over 1.9 billion users currently. The document also outlines the various technologies and standards that underpin modern Internet infrastructure like IP addressing, domains, and connection types.
Here are the number of broadcast and collision domains for each case:
1. A single switch with 10 connected devices:
- Broadcast domain: 1
- Collision domain: 10 (each switch port is its own collision domain)
2. Two switches connected by a single trunk link with 10 devices on each switch:
- Broadcast domain: 2 (each switch is its own broadcast domain)
- Collision domain: 20 (each switch port is its own collision domain)
3. A router connecting two switches, each with 10 devices:
- Broadcast domain: 3 (each physical network segment is its own broadcast domain)
- Collision domain: 20 (each switch port is its own collision domain)
This document provides an introduction to data communications and networking. It discusses the history of communications technologies from the telegraph to the internet. It then describes common communication models including the OSI 7-layer model and TCP/IP protocol stack. Key topics covered include data transmission, networking, protocols, standards, and the physical, data link, network, transport, and application layers. The document aims to explain why we study communications and provide context around important concepts, models, protocols and the development of the internet.
Modue 1 part 1 of computer networks for your university examsvish21ainds
A computer network (CN) is a group of devices that share resources over a network, with each device represented as a network node. The devices communicate with each other using standard protocols to send or receive data.
Computers on a network can be linked through cables, radio waves, telephone lines, infrared light beams, or satellites. The network can also include other devices that help in communication, known as network devices.
Here are some types of computer networks:
PAN (Personal Area Network): The smallest and simplest type of network
LAN (Local Area Network): The most frequently used network, connecting computers within a limited area, such as a single office or building
MAN (Metropolitan Area Network): A type of network
WAN (Wide Area Network): An enterprise network spanning cities, buildings, and even countries
Wireless networking is about creating and managing wireless connections, commonly used in Wi-Fi. This involves setting up Wi-Fi routers, securing them with passwords, and allowing devices to connect to a network without using physical cables.
A network connects computers together to share resources. It has physical components like cables and wireless media, and logical components to transport data across the physical layer. Common network topologies include star, bus, ring and mesh configurations. Switches and routers are key devices that intelligently direct traffic in a network. Ethernet is a widely-used networking standard that supports various cabling types and speeds up to gigabit connections.
The document discusses network standards and models including:
- Network communication involves recognizing data, dividing it into chunks, and adding information to determine source/destination and for error checking before sending.
- Standards are needed for hardware/software from different vendors to communicate through standard protocols that control tasks like these.
- There are formal standards developed by standards bodies and de facto standards that emerge in the marketplace.
- Key networking standards organizations that develop standards through specification, identification of solutions, and acceptance processes are ANSI, IEEE, ISO, and ITU.
The document discusses various network models including peer-to-peer networks where computers operate as equals, client-server networks where some computers provide services to others, and hybrid networks that combine aspects of different models. It also describes two-tier and three-tier client-server architectures, with three-tier adding an application server layer to improve efficiency and security over the two-tier approach. Finally, it introduces network reference models like OSI and TCP/IP that define standards for network communication.
The document provides an overview of the history and development of the Internet. It discusses how the Internet began as a US military network called ARPAnet in 1969 and expanded throughout the 1970s. While initially used by researchers and the military, the creation of the World Wide Web in the early 1990s led to widespread commercial and public use of the Internet with over 1.9 billion users currently. The document also outlines the various technologies and standards that underpin modern Internet infrastructure like IP addressing, domains, and connection types.
Here are the number of broadcast and collision domains for each case:
1. A single switch with 10 connected devices:
- Broadcast domain: 1
- Collision domain: 10 (each switch port is its own collision domain)
2. Two switches connected by a single trunk link with 10 devices on each switch:
- Broadcast domain: 2 (each switch is its own broadcast domain)
- Collision domain: 20 (each switch port is its own collision domain)
3. A router connecting two switches, each with 10 devices:
- Broadcast domain: 3 (each physical network segment is its own broadcast domain)
- Collision domain: 20 (each switch port is its own collision domain)
Here are the number of broadcast and collision domains for each case:
1. A single switch with 10 connected devices:
- Broadcast domain: 1
- Collision domain: 10 (each switch port is its own collision domain)
2. Two switches connected by a single trunk link with 10 devices on each switch:
- Broadcast domain: 2
- Collision domain: 20 (each switch port is its own collision domain)
3. A router connected to two switches, with 10 devices on each switch:
- Broadcast domain: 3
- Collision domain: 20 (each switch port is its own collision domain)
This document provides an overview of networking fundamentals including network history, topologies, protocols, and devices. It discusses the evolution of networks from standalone computers connecting via modems to today's large networks. It describes common network topologies like bus, star, and ring. The document outlines the OSI and TCP/IP models and explains the functions of common networking devices like hubs, bridges, routers, and gateways. It also covers wired media like coaxial cable and fiber optic cable as well as wireless networking standards.
This document provides an overview of computer networks. It defines what a computer network is and some common network types, including local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). It also discusses network topologies, hardware components, and protocols like SLIP and PPP. The key topics covered include the basic components of a computer network, common network models, networking devices, and differences between SLIP and PPP protocols.
The document discusses two reference models for networking - the OSI model and the TCP/IP model. The OSI model has 7 layers including physical, data link, network, transport, session, presentation and application layers. The TCP/IP model has 4 layers - application, transport, internet and link layers. Both models organize networking functions into logical layers to reduce complexity. While similar, the OSI model was designed before protocols existed while TCP/IP protocols like IP, TCP and UDP were developed first.
The document discusses the OSI reference model, which was developed by ISO in 1984 to standardize network communication. It describes the need for standards due to incompatible networks. The OSI model organizes network functions into seven layers, with each layer providing services to the layer above and handling distinct network duties like physical transmission, routing, and application support. This layered approach reduces complexity and promotes interoperability between different network technologies.
Entrepreneurship & Commerce in IT - 09 - The internet and the world wide webSachintha Gunasena
The document discusses the evolution and key concepts of the Internet. It describes how packet switching, TCP/IP, and client-server computing enabled the Internet to develop. Packet switching allowed messages to be broken into packets and sent over multiple paths. TCP/IP provided protocols for transmitting and routing these packets. Client-server models distributed processing power across many connected computers. Together these innovations formed the basis of the Internet and World Wide Web.
1) The document outlines a course on data communication and networks across 5 units. It covers topics such as network fundamentals, data link layer, network layer, transport layer, and applications.
2) The objectives are to understand basic network concepts, components for data communication, analyze functions of various layers, and acquire knowledge of application protocols and internet technologies.
3) The outcomes are to understand how information flows through a network, identify components for different network types, understand the layered approach to data communication, and choose appropriate functionality for applications.
This chapter discusses telecommunications and computer networks for business. It covers data transmission units and technologies, types of networks including LANs, WANs and intranets. It describes network devices, switching methods, the OSI model layers and TCP/IP. Intranets and extranets are defined, and applications for internal networks and sharing information with business partners are provided. Internet addressing systems using IP classes are also summarized.
This presentation is all about the internet basics we need to know before making a website or some other internet related works . This will help you to have a clear idea on What Is Internet.
Thank you
feel free to ask any queries in comment box
This document provides an overview of computer networks and communication. It discusses key topics such as data communication components and models, data representation, transmission modes, network types and topologies, protocols and standards. The key points are:
- Data communication involves exchanging data between devices via transmission medium using agreed upon protocols. Its effectiveness depends on delivery, accuracy, timeliness and jitter.
- Networks connect devices through various physical topologies like star, bus, ring and hybrid configurations. They can be LAN, MAN or WAN depending on size and distance covered.
- Protocols and standards govern data communication and ensure interoperability. They are developed by organizations like ISO, ITU, IEEE and adopted as industry
Lecture3 - Computer Networks by the Professor.pptHamzaIqbal900476
The document provides an introduction to computer networks. It discusses that a network is a set of communication elements like computers, printers, and routers connected by communication links like fiber optic cables. Networks allow sharing of resources and information between users. The key components of a network are its topology, hardware, software, and applications. Common network topologies include ring, star, bus, tree and mesh configurations.
The document provides information about the history and development of the Internet. It discusses how the Internet began as a US military network called ARPANET in 1969 and expanded throughout the 1970s. It also describes how the creation of the World Wide Web in 1991 by Tim Berners-Lee led to widespread commercial and public use of the Internet. The document then gives an overview of Internet governance organizations and different types of Internet connections.
This document discusses key concepts related to computer networking including:
- The benefits of networking such as sharing hardware/software resources and information.
- Types of networks like local area networks (LANs) and wide area networks (WANs).
- Layered network architectures and protocols that define rules for communication between layers.
- Common reference models for networking including the OSI model and TCP/IP model.
The document discusses the Internet and computer networks. It begins by explaining how the Internet emerged from early experiments connecting computers. It then describes different types of computer networks including local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). It also discusses wireless networks like Wi-Fi and Bluetooth. The document then explains client-server networks and peer-to-peer networks. It provides details on topics like IP addressing, URLs, DNS hierarchy, and accessing the Internet via methods such as dial-up, broadband, and wireless. Finally, it briefly discusses web browsers and cyber ethics.
The document discusses network security models and the OSI reference model. It describes the seven layers of the OSI model from the physical layer to the application layer. It then discusses the TCP/IP reference model and its four layers from the link layer to the application layer. The document summarizes key protocols associated with each layer, including IP, TCP, UDP, and protocols that provide security at the transport and network layers like SSL/TLS and IPSec.
The document discusses computer networks and networking concepts. It defines a computer network as an interconnection of two or more computers that allows users to share information and resources. The document describes two common network models - the peer-to-peer and client/server models. It also explains the seven layer OSI reference model and compares it to the four layer TCP/IP model. Finally, it categorizes different types of networks including LANs, MANs, WANs, PANs, wireless networks, and home networks.
This document provides an overview of data communication networks and the Internet. It discusses the history of computer networks from the 1960s focusing on efficient and reliable transmission. It also describes the basic components of a communication network including devices, media, and structures like point-to-point and broadcast networks. The document then introduces the ISO-OSI reference model and its seven layer architecture for standardizing network communication. It concludes with descriptions of connection-oriented and connectionless communication services.
This document provides an overview of computer networks. It begins by defining a network as two or more connected computers and describes the main types as local area networks (LANs) and wide area networks (WANs). LANs are confined to a limited geographical area while WANs cover a larger area and are often composed of multiple connected LANs. The document then discusses specific network types like LANs, WANs, MANs, and PANs. It also outlines the benefits of networks like information sharing, hardware sharing, software sharing, and collaborative environments. However, it notes networks also face risks from equipment malfunctions, system failures, computer hackers, and virus attacks. The document concludes by discussing network
This presentation is about:
Uses of Networking.
Various types of networking.
Applications used for networking.
Methods of network security.
Methods of communication -2G,3G,4G,Fiber Optics
Transmission Media.
Various types of protocols.
Cloud Computing
Protection against Viruses.
Covid Management System Project Report.pdfKamal Acharya
CoVID-19 sprang up in Wuhan China in November 2019 and was declared a pandemic by the in January 2020 World Health Organization (WHO). Like the Spanish flu of 1918 that claimed millions of lives, the COVID-19 has caused the demise of thousands with China, Italy, Spain, USA and India having the highest statistics on infection and mortality rates. Regardless of existing sophisticated technologies and medical science, the spread has continued to surge high. With this COVID-19 Management System, organizations can respond virtually to the COVID-19 pandemic and protect, educate and care for citizens in the community in a quick and effective manner. This comprehensive solution not only helps in containing the virus but also proactively empowers both citizens and care providers to minimize the spread of the virus through targeted strategies and education.
Sachpazis_Consolidation Settlement Calculation Program-The Python Code and th...Dr.Costas Sachpazis
Consolidation Settlement Calculation Program-The Python Code
By Professor Dr. Costas Sachpazis, Civil Engineer & Geologist
This program calculates the consolidation settlement for a foundation based on soil layer properties and foundation data. It allows users to input multiple soil layers and foundation characteristics to determine the total settlement.
Here are the number of broadcast and collision domains for each case:
1. A single switch with 10 connected devices:
- Broadcast domain: 1
- Collision domain: 10 (each switch port is its own collision domain)
2. Two switches connected by a single trunk link with 10 devices on each switch:
- Broadcast domain: 2
- Collision domain: 20 (each switch port is its own collision domain)
3. A router connected to two switches, with 10 devices on each switch:
- Broadcast domain: 3
- Collision domain: 20 (each switch port is its own collision domain)
This document provides an overview of networking fundamentals including network history, topologies, protocols, and devices. It discusses the evolution of networks from standalone computers connecting via modems to today's large networks. It describes common network topologies like bus, star, and ring. The document outlines the OSI and TCP/IP models and explains the functions of common networking devices like hubs, bridges, routers, and gateways. It also covers wired media like coaxial cable and fiber optic cable as well as wireless networking standards.
This document provides an overview of computer networks. It defines what a computer network is and some common network types, including local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). It also discusses network topologies, hardware components, and protocols like SLIP and PPP. The key topics covered include the basic components of a computer network, common network models, networking devices, and differences between SLIP and PPP protocols.
The document discusses two reference models for networking - the OSI model and the TCP/IP model. The OSI model has 7 layers including physical, data link, network, transport, session, presentation and application layers. The TCP/IP model has 4 layers - application, transport, internet and link layers. Both models organize networking functions into logical layers to reduce complexity. While similar, the OSI model was designed before protocols existed while TCP/IP protocols like IP, TCP and UDP were developed first.
The document discusses the OSI reference model, which was developed by ISO in 1984 to standardize network communication. It describes the need for standards due to incompatible networks. The OSI model organizes network functions into seven layers, with each layer providing services to the layer above and handling distinct network duties like physical transmission, routing, and application support. This layered approach reduces complexity and promotes interoperability between different network technologies.
Entrepreneurship & Commerce in IT - 09 - The internet and the world wide webSachintha Gunasena
The document discusses the evolution and key concepts of the Internet. It describes how packet switching, TCP/IP, and client-server computing enabled the Internet to develop. Packet switching allowed messages to be broken into packets and sent over multiple paths. TCP/IP provided protocols for transmitting and routing these packets. Client-server models distributed processing power across many connected computers. Together these innovations formed the basis of the Internet and World Wide Web.
1) The document outlines a course on data communication and networks across 5 units. It covers topics such as network fundamentals, data link layer, network layer, transport layer, and applications.
2) The objectives are to understand basic network concepts, components for data communication, analyze functions of various layers, and acquire knowledge of application protocols and internet technologies.
3) The outcomes are to understand how information flows through a network, identify components for different network types, understand the layered approach to data communication, and choose appropriate functionality for applications.
This chapter discusses telecommunications and computer networks for business. It covers data transmission units and technologies, types of networks including LANs, WANs and intranets. It describes network devices, switching methods, the OSI model layers and TCP/IP. Intranets and extranets are defined, and applications for internal networks and sharing information with business partners are provided. Internet addressing systems using IP classes are also summarized.
This presentation is all about the internet basics we need to know before making a website or some other internet related works . This will help you to have a clear idea on What Is Internet.
Thank you
feel free to ask any queries in comment box
This document provides an overview of computer networks and communication. It discusses key topics such as data communication components and models, data representation, transmission modes, network types and topologies, protocols and standards. The key points are:
- Data communication involves exchanging data between devices via transmission medium using agreed upon protocols. Its effectiveness depends on delivery, accuracy, timeliness and jitter.
- Networks connect devices through various physical topologies like star, bus, ring and hybrid configurations. They can be LAN, MAN or WAN depending on size and distance covered.
- Protocols and standards govern data communication and ensure interoperability. They are developed by organizations like ISO, ITU, IEEE and adopted as industry
Lecture3 - Computer Networks by the Professor.pptHamzaIqbal900476
The document provides an introduction to computer networks. It discusses that a network is a set of communication elements like computers, printers, and routers connected by communication links like fiber optic cables. Networks allow sharing of resources and information between users. The key components of a network are its topology, hardware, software, and applications. Common network topologies include ring, star, bus, tree and mesh configurations.
The document provides information about the history and development of the Internet. It discusses how the Internet began as a US military network called ARPANET in 1969 and expanded throughout the 1970s. It also describes how the creation of the World Wide Web in 1991 by Tim Berners-Lee led to widespread commercial and public use of the Internet. The document then gives an overview of Internet governance organizations and different types of Internet connections.
This document discusses key concepts related to computer networking including:
- The benefits of networking such as sharing hardware/software resources and information.
- Types of networks like local area networks (LANs) and wide area networks (WANs).
- Layered network architectures and protocols that define rules for communication between layers.
- Common reference models for networking including the OSI model and TCP/IP model.
The document discusses the Internet and computer networks. It begins by explaining how the Internet emerged from early experiments connecting computers. It then describes different types of computer networks including local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). It also discusses wireless networks like Wi-Fi and Bluetooth. The document then explains client-server networks and peer-to-peer networks. It provides details on topics like IP addressing, URLs, DNS hierarchy, and accessing the Internet via methods such as dial-up, broadband, and wireless. Finally, it briefly discusses web browsers and cyber ethics.
The document discusses network security models and the OSI reference model. It describes the seven layers of the OSI model from the physical layer to the application layer. It then discusses the TCP/IP reference model and its four layers from the link layer to the application layer. The document summarizes key protocols associated with each layer, including IP, TCP, UDP, and protocols that provide security at the transport and network layers like SSL/TLS and IPSec.
The document discusses computer networks and networking concepts. It defines a computer network as an interconnection of two or more computers that allows users to share information and resources. The document describes two common network models - the peer-to-peer and client/server models. It also explains the seven layer OSI reference model and compares it to the four layer TCP/IP model. Finally, it categorizes different types of networks including LANs, MANs, WANs, PANs, wireless networks, and home networks.
This document provides an overview of data communication networks and the Internet. It discusses the history of computer networks from the 1960s focusing on efficient and reliable transmission. It also describes the basic components of a communication network including devices, media, and structures like point-to-point and broadcast networks. The document then introduces the ISO-OSI reference model and its seven layer architecture for standardizing network communication. It concludes with descriptions of connection-oriented and connectionless communication services.
This document provides an overview of computer networks. It begins by defining a network as two or more connected computers and describes the main types as local area networks (LANs) and wide area networks (WANs). LANs are confined to a limited geographical area while WANs cover a larger area and are often composed of multiple connected LANs. The document then discusses specific network types like LANs, WANs, MANs, and PANs. It also outlines the benefits of networks like information sharing, hardware sharing, software sharing, and collaborative environments. However, it notes networks also face risks from equipment malfunctions, system failures, computer hackers, and virus attacks. The document concludes by discussing network
This presentation is about:
Uses of Networking.
Various types of networking.
Applications used for networking.
Methods of network security.
Methods of communication -2G,3G,4G,Fiber Optics
Transmission Media.
Various types of protocols.
Cloud Computing
Protection against Viruses.
Covid Management System Project Report.pdfKamal Acharya
CoVID-19 sprang up in Wuhan China in November 2019 and was declared a pandemic by the in January 2020 World Health Organization (WHO). Like the Spanish flu of 1918 that claimed millions of lives, the COVID-19 has caused the demise of thousands with China, Italy, Spain, USA and India having the highest statistics on infection and mortality rates. Regardless of existing sophisticated technologies and medical science, the spread has continued to surge high. With this COVID-19 Management System, organizations can respond virtually to the COVID-19 pandemic and protect, educate and care for citizens in the community in a quick and effective manner. This comprehensive solution not only helps in containing the virus but also proactively empowers both citizens and care providers to minimize the spread of the virus through targeted strategies and education.
Sachpazis_Consolidation Settlement Calculation Program-The Python Code and th...Dr.Costas Sachpazis
Consolidation Settlement Calculation Program-The Python Code
By Professor Dr. Costas Sachpazis, Civil Engineer & Geologist
This program calculates the consolidation settlement for a foundation based on soil layer properties and foundation data. It allows users to input multiple soil layers and foundation characteristics to determine the total settlement.
We have designed & manufacture the Lubi Valves LBF series type of Butterfly Valves for General Utility Water applications as well as for HVAC applications.
Particle Swarm Optimization–Long Short-Term Memory based Channel Estimation w...IJCNCJournal
Paper Title
Particle Swarm Optimization–Long Short-Term Memory based Channel Estimation with Hybrid Beam Forming Power Transfer in WSN-IoT Applications
Authors
Reginald Jude Sixtus J and Tamilarasi Muthu, Puducherry Technological University, India
Abstract
Non-Orthogonal Multiple Access (NOMA) helps to overcome various difficulties in future technology wireless communications. NOMA, when utilized with millimeter wave multiple-input multiple-output (MIMO) systems, channel estimation becomes extremely difficult. For reaping the benefits of the NOMA and mm-Wave combination, effective channel estimation is required. In this paper, we propose an enhanced particle swarm optimization based long short-term memory estimator network (PSOLSTMEstNet), which is a neural network model that can be employed to forecast the bandwidth required in the mm-Wave MIMO network. The prime advantage of the LSTM is that it has the capability of dynamically adapting to the functioning pattern of fluctuating channel state. The LSTM stage with adaptive coding and modulation enhances the BER.PSO algorithm is employed to optimize input weights of LSTM network. The modified algorithm splits the power by channel condition of every single user. Participants will be first sorted into distinct groups depending upon respective channel conditions, using a hybrid beamforming approach. The network characteristics are fine-estimated using PSO-LSTMEstNet after a rough approximation of channels parameters derived from the received data.
Keywords
Signal to Noise Ratio (SNR), Bit Error Rate (BER), mm-Wave, MIMO, NOMA, deep learning, optimization.
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Here's where you can reach us : ijcnc@airccse.org or ijcnc@aircconline.com
5. A Brief History about
Communications
• 1837- Samuel Morse invented the telegraph.
Coding is done with the Morse code
• 1876- Alex. Graham Bell invented the telephone.
Voice is converted into electrical energy and
transmitted over a wire.
• 1945- ENIAC was invented as the first electronic
computer
• 1980s-Personal Computers become a new way of
computing
• 1990s-came the emergence of the Internet and
World Wide Web applications
6. What are transmitted via
Communication Media?
• Voice – encoded signals
• Video – encoded images
• Data – character streams
7. Communication Applications
• Voice – telephone, FAX, Video
Conferencing, Cellular phones, etc.
• Video & Audio – television, VCR, DVD,
etc.
• Data – LAN, WAN, Internet, etc.
8. Networking
• Networking—computers communicate with
each other via networks.
• Computer network—a communication
system for connecting computers using a
single transmission technology.
10. Network Topology
• Bus topology
• Star topology
• Ring topology
• Fully connected topology
• Combined topology
11. Protocols
• Definition – all parties involved in a
communication must agree in a set of rules to be
used when exchanging messages. Thus, the set of
rules which both the sender and the receiver all
comply with is called protocol.
• A protocol specifies the message format,
meanings, and the procedures is known as a
communication protocol.
• A communication application doesn’t
communicate with the communication hardware
directly.
12. Key Elements of a Protocol
• Syntax
– Data formats
– Signal levels
• Semantics
– Control information
– Error handling
• Timing
– Speed matching
– Sequencing
13. Why Protocols?
• Used for communications between entities in a
system
• Must speak the same language
• Entities
– User applications
– e-mail facilities
– terminals
• Systems
– Computer
– Terminal
– Remote sensor
14. Communication Reference
Models
• In summary, we need a communication reference
model to describe the relationship between various
software and hardware.
• A reference model describes the layering
relationship of software and hardware involved in
the communication.
• A layered protocol performs specific functions and
communicates with the layers directly above and
below it.
15. Communication Reference
Models
• The purpose of layering the protocol is to separate
specific functions and to make their
implementation transparent to other components.
• Advantage of layered approach: independent
design and testing of each communication
software component
• Disadvantage: overly layering can affect
performance negatively.
16. A Communications Model
• Source
– generates data to be transmitted
• Transmitter
– Converts data into transmittable signals
• Transmission System
– Carries data
• Receiver
– Converts received signal into data
• Destination
– Takes incoming data
17. Protocol Architecture
• Task of communication broken up into
modules
• For example file transfer could use three
modules
– File transfer application
– Communication service module
– Network access module
18. Protocol Data Units (PDU)
• At each layer, protocols are used to communicate
• Control information is added to user data at each
layer
• Transport layer may fragment user data
• Each fragment has a transport header added
– Destination SAP
– Sequence number
– Error detection code
• This gives a transport protocol data unit
19. Standards
• Required to allow for interoperability between
equipment
• Advantages
– Ensures a large market for equipment and software
– Allows products from different vendors to
communicate
• Disadvantages
– Freeze technology
– May be multiple standards for the same thing
20. Categories of Protocols
• Proprietary system– designed and developed for
supporting the communications of machines
manufactured by a specific vender
• System Network Architecture (SNA) was designed and
developed for connecting IBM main frame computers
and peripherals (workstations, printers, tape drives, etc.)
• NetBEUI – Microsoft’s protocol for simple Windows
networks
• IPX/SPX (Internetwork Packet Exchange and
Sequenced Packet exchange) – support Novell NetWare
products
21. Categories of Protocols
• Open systems– publicly proposed and evaluated
protocols for supporting the internetworking of
heterogeneous machine
• Open System Interconnect (OSI) was developed by ISO
• TCP/IP was designed by IETF (Internet Engineering
Task Force), another volunteer organization for the
engineering issues of the Internet.
23. OSI Model
• Open Systems Interconnection (OSI)
• Developed by the International
Organization for Standardization (ISO)
• Seven layers
• A theoretical system delivered too late!
• TCP/IP is the de facto standard
27. Physical Layer
• Corresponds to basic hardware.
• Example: NIC, modem, cable
• Topics include transmission media, data
encoding, modulation/demodulation,
multiplexing, switching(layer 1)-- circuit
switching.
28. Data Link Layer
• Specifies how to organize data into frames
and how to transmit frames over a network.
• Detail topics include the format of a data
frame, i.e., framing, error
detection/correction, frame level error
recovery.
29. Network Layer
• Specifies how to assign addresses and how
to forward packets to its destination.
• Detail topics include fragmentation,
assembly, routing, flow control.
30. Transport Layer
• The basic function of the transport layer is
to accept data from the session layer, split it
up into smaller units, if needed, pass them
to the network layer, and ensure that the
pieces all arrive correctly at the other end.
• The transport layer also determines the type
of services, connection-oriented or
connectionless.
• Congestion control
31. Session Layer
• Allows users on different machines to
establish sessions between them.
• Major functions include managing dialog.
• Session layer determines whether traffic
can only go in one direction or both
directions at the same time.
33. Application Layer
• Controls the interface with users.
• Application, presentation, session layers are
usually implemented together instead of
using laying architecture.
34. TCP/IP Protocol Architecture
• Developed by the US Defense Advanced Research
Project Agency (DARPA) for its packet switched
network (ARPANET)
• Used by the global Internet
• No official model but a working one.
– Application layer
– Transport layer: host-to-host (application to application)
– Internet layer: network routing and congestion control
– Network access layer: access transmission medium
– Physical layer
36. The Internet
• Explosive growth –
– starts out as a research project of a few dozen nodes.
Now, it spans 82 countries and has millions of nodes.
– It has been growing exponentially since its inception.
• Used in all Venues-
– Government
– Education
– Private companies
37. History of the Internet
• Late 60s—the U.S. government realizes the
importance of allowing their research and
development sites to electronically “talk” to each
other. The government-funded Advanced Research
Projects Agency(DARPA) created ARPANET in
1969.
• Mid 1970’s – ARPA began to work on connecting
computers in all associated agencies. The early
Internet had emerged.
38. History of the Internet(cont’d)
• Mid 1980’ – the Internet split into
ARPANET and MILNET.
• 1986 – NSFNET began to work; the
National Science Foundation funded a new
wide area network that connected all of its
supercomputing centers.
• 1996 – Telecommunications Reform Act.
39. Who run the Internet?
• No one person, group or organization owns. The
backbone of it is funded by the National Science
Foundation in the U.S.
• In addition, there is an Internet Engineering Task
Force (IETF) and Internet Advisory Board (IAB)
who help to set standards (TCP/IP) for those who
wish to connect to, and use, the Internet.
• The IAB makes its standard available via
documents called RFC (Request for Comment).
40. What is TCP/IP?
• TCP/IP stands for Transmission Control
Protocol/Internet Protocol and is actually a set of
standards that describe how data is to be
transferred between computers.
• TCP/IP is the common tongue that all computers
must speak to communicate via Internet.
• There are implementations for UNIX, Windows,
Macintosh, and just about any computer operating
systems you can think of.
• TCP/IP is implemented as part of an Operating
System.
41. Other Names of the Internet
• ARPANET : the U.S. Department of
Defense Advanced Research Projects
(ARPA)
• The TCP/IP Internet
• The (Global) Internet
42. Physical Layer
• Physical interface between data
transmission device (e.g. computer) and
transmission medium or network
• Characteristics of transmission medium
• Signal levels
• Data rates
• etc.
43. Network Access Layer
• Exchange of data between end system and
network
• Destination address provision
• Invoking services like priority
44. Internet Layer (IP)
• Systems may be attached to different
networks
• Routing functions across multiple networks
• Implemented in end systems and routers
48. Plethora of Terminology:where
do they come from?
• Hardware – switches, nodes, boxes, bridges,
routers, gateways, etc.
• Software – protocol, seven protocol layers,
protocol stack, protocol suite, etc.
• Market – computer venders “invent” new term to
make a mint.
• Politics – “the Information Highway”.
• Computer research community – objected-oriented
technology, CORBA(Common Object Request
Broker Architecture), Java, JavaScript, Dynamic
Java, Java 2, etc.
49. What’s Next? – Data
Transmission
• Two issues—
– Medium
– Form of energy
• READING ASSIGNMENT:
– Chapter 1 (ignoring some details)
50. Extra Reading Material
• Stallings, W. Data and Computer Communications
(6th edition), Prentice Hall 1999 chapter 1
• Web site for Stallings book
– www.shore.net/~ws/DCC6e.html
• Web sites for IETF, IEEE, ITU-T, ISO
• Internet Requests for Comment (RFCs)
• Usenet News groups
– comp.dcom.*
– comp.protocols.tcp-ip