Lecture 14.pptx best presentation about internet
- 2. 2 How Networks Impact Daily Life Describe the characteristics and purpose of popular communication media such as, IM, Wikis , Blogs, Podcasting, and Collaboration Tools – Instant messaging • Real time communication between 2 or more people based on typed text – Weblogs (Blogs) • Web pages created by an individual – Podcasting • Website that contains audio files available for downloading
- 3. 3 Data Networking Role, Components, and Challenges Basic characteristics of communication – Rules or agreements are 1st established – Important information may need to be repeated – Various modes of communication may impact the effectiveness of getting the message across
- 4. 4 Data Networking Role, Components, and Challenges Describe the various elements that make up a network – Devices • These are used to communicate with one another – Medium • This is how the devices are connected together – Messages • Information that travels over the medium – Rules • Governs how messages flow across network
- 5. 5 Data Networking Role, Components, and Challenges Describe the role of converged networks in communications – Converged network • A type of network that can carry voice, video & data over the same network
- 7. 7 Data Communications The term telecommunication means communication at a distance. The word data refers to information presented in whatever form is agreed upon by the parties creating and using the data. Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable. Components of a data communications system Data Flow Topics discussed in this section:
- 8. 8 Figure 1.1 Components of a data communication system Components
- 9. 9 Figure 1.2 Data flow (simplex, half-duplex, and full-duplex) Data Flow
- 10. 10 Networks A network is a set of devices (often referred to as nodes) connected by communication links. A node can be a computer, printer, or any other device capable of sending and/or receiving data generated by other nodes on the network. A link can be a cable, air, optical fiber, or any medium which can transport a signal carrying information. Network Criteria Physical Structures Categories of Networks Topics discussed in this section:
- 11. 11 Network Criteria Performance – Depends on Network Elements – Measured in terms of Delay and Throughput Reliability – Failure rate of network components – Measured in terms of availability/robustness Security – Data protection against corruption/loss of data due to: – Errors – Malicious users
- 12. 12 Physical Structures Type of Connection – Point to Point - single transmitter and receiver – Multipoint - multiple recipients of single transmission Physical Topology – Connection of devices – Type of transmission – • Unicast, Multicast, Broadcast
- 13. 13 Figure 1.3 Types of connections: point-to-point and multipoint Types of Connection
- 14. 14 Topologies Topology is the physical layout or arrangement of devices connected together in a network. Figure 1.4 Categories of topology
- 15. 15 Mesh Topology Figure 1.5 A fully connected mesh topology (five devices)
- 16. 16 Star Topology Figure 1.6 A star topology connecting four stations
- 17. 17 Bus Topology Figure 1.7 A bus topology connecting three stations
- 18. 18 Ring Topology Figure 1.8 A ring topology connecting six stations
- 19. 19 Hybrid Topology Figure 1.9 A hybrid topology: a star backbone with three bus networks
- 20. 20 Network Structure Define the elements of communication – 3 common elements of communication • Message source • The channel • Message destination Define a network – Data or information networks capable of carrying many different types of communications
- 21. 21 Network Structure Describe how messages are communicated – Data is sent across a network in small “chunks” called segments
- 22. 22 Network Structure Define the components of a network – Network components • Hardware • Software
- 23. 23 Network Structure End Devices and their Role in the Network – End devices form interface with human network & communications network – Role of end devices: • Client • Server • Both client and server
- 24. 24 Network Structure Identify the role of an intermediary device in a data network and be able to contrast that role with the role of an end device – Role of an intermediary device • Provides connectivity and ensures data flows across network
- 25. 25 Network Structure Define network media and criteria for making a network media choice – Network media – this is the channel over which a message travels
- 26. 26 Network Categories Local Area Networks (LANs) – Short distances – Designed to provide local interconnectivity Metropolitan Area Networks (MANs) – Provide connectivity over areas such as a city, a campus Wide Area Networks (WANs) – Long distances – Provide connectivity over large areas
- 27. 27 Local Area Network Figure 1.10 An isolated LAN connecting 12 computers to a hub in a closet
- 28. 28 LAN
- 29. 29 LAN
- 32. 32 Figure 1.11 WANs: a switched WAN and a point-to-point WAN WAN
- 33. 33 Heterogeneous Network Figure 1.12 A heterogeneous network made of four WANs and two LANs
- 34. 34 Protocols Network protocols: Machines rather than humans All communication activity in Internet governed by protocols Human protocols: “what’s the time?” “I have a question” introductions Q: Why are protocols so important? Hi Hi Got the time? 2:00 TCP connection req TCP connection response Get http://www.awl.com/kurose-ross <file> time
- 35. 35 Protocol A protocol is synonymous with rule. It consists of a set of rules that govern data communications. It determines what is communicated, how it is communicated and when it is communicated. The key elements of a protocol are syntax, semantics and timing Syntax Semantics Timing Topics discussed in this section:
- 36. 36 Elements Of Protocol Syntax – Structure or format of the data – Indicates how to read the bits - field delineation Semantics – Interprets the meaning of the bits – Knows which fields define what action Timing – When data should be sent and what – Speed at which data should be sent or speed at which it is being received.
- 37. 37 Function of Protocol in Network Communication The importance of protocols and how they are used to facilitate communication over data networks – A protocol is a set of predetermined rules
- 38. 38 Function of Protocol in Network Communication Explain network protocols – Network protocols are used to allow devices to communicate successfully
- 39. 39 Function of Protocol in Network Communication Describe Protocol suites and industry standards – A standard is a process or protocol that has been endorsed by the networking industry and ratified by a standards organization
- 40. 40 Function of Protocol in Network Communication Technology independent Protocols – Many diverse types of devices can communicate using the same sets of protocols – This is because protocols specify network functionality, not the underlying technology to support this functionality
- 41. 41 Standards