Layers of tcpip.65 to 66


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Layers of tcpip.65 to 66

  1. 1. Topic : Basics of WAN & WAN ProtocolsSub-Topic : Describe Different Layers of TCP/IP 1
  2. 2. Recap In the previous classes, you have learnt about• Packet transfer mechanism in Routers using IP address 2
  3. 3. Objectives On completion of this period, you will be able to know about• Functions of different layers of TCP/IP• Various protocols used in different layers• Importance of TCP/IP architecture 3
  4. 4. Recap What is the network architecture that we have alreadystudied ? ISO – OSI Model 4
  5. 5. How many layers it has and name them ? Seven - Application • Presentation • Session • Transport • Network • Data link • Physical 5
  6. 6. OSI Model Application Presentation Session Transport Network Data link PhysicalFig .1 6
  7. 7. Need for TCP/IP• OSI model has seven layers in it• Two of the layers namely presentation and session layers were rarely used• OSI architecture is rigidly structured• As the technologies developed there was a need for a new architecture• Presentation and session layers are eliminated• TCP/IP architecture has evolved to overcome the shortcomings of OSI model 7
  8. 8. TCP/IP Model Application Not present in the model Transport Internet Host-to-networkFig .2 8
  9. 9. Layer Level Comparisons OSI TCP / IPApplication ApplicationTransport TransportNetwork InternetData link Host-to-NetworkPhysical 9
  10. 10. Differences in Architectural Models• OSI Network architecture model does not permit communication between different heterogeneous networks• It does not support the latest networks developed 10
  11. 11. Differences in Architectural Models (Contd…)• TCP/IP network architecture allows us to communicate between any heterogeneous networks• It is flexible and ready to change its architectural structure to support the newly introduced networks• For Ex: The wireless communication networks also can be interconnected to the existing wired networks 11
  12. 12. Functions of the TCP/IP LayersHost-to-Network Layer • It is the lowest layer in this model • It is equivalent to the Physical layer of OSI model • The TCP/IP reference model does not really say much about what happens in this layer 12
  13. 13. Host-to-Network Layer (Contd…)• It points out that the host has to connect to the network using some protocol so it can send IP packets over it• This protocol is not clearly defined and varies from host to host and network to network• It is concerned with the physical characteristics of the medium, connectors, voltage levels etc 13
  14. 14. Internet Layer• Internet layer is the lynchpin that holds the whole architecture together• Its job is to permit hosts to inject packets into any network and have them travel independently to the destination• The destination can be in a local network or different network 14
  15. 15. Internet Layer•They may even arrive in a different order than they weresent, in which case it is the job of higher layers to rearrangethem•The internet layer defines an official packet format andprotocol called IP (Internet Protocol) 15
  16. 16. Internet Layer ( contd…)• Packet routing is clearly the major issue here, as is avoiding congestion• This layer also performs congestion control i.e. it can divert the data traffic to other routes to ease the congestion• TCP/IP internet layer is very similar in functionality to the OSI network layer 16
  17. 17. Transport Layer• The layer above the internet layer in the TCP/IP model• It is designed to allow peer entities on the source and destination hosts to carry on a conversation• Two end-to-end protocols have been defined here a) Transmission control protocol b) User data gram protocol 17
  18. 18. Transport Layer (Contd…)•The first one, TCP (Transmission Control Protocol) is areliable connection-oriented protocol.•It fragments the incoming byte stream into discretemessages and passes each one onto the internet layer.•TCP allows a byte stream originating on one machine tobe delivered without error on to any other machine in theinternet. 18
  19. 19. Transport Layer (Contd…)• At the destination, the receiving TCP process reassembles the received messages into the output stream• TCP also handles flow control• It makes sure that a fast sender cannot swamp a slow receiver with more messages than it can handle 19
  20. 20. Transport Layer (Contd…)UDP Protocol • The second protocol in this layer is UDP (User Datagram Protocol) • UDP an unreliable, connectionless protocol for applications that do not want TCP’s sequencing or flow control 20
  21. 21. UDP Protocol contd…•It is widely used for one-short, client-server type request-reply queries•It is used in applications in which prompt delivery is moreimportant than accurate delivery, such as transmittingspeech or video 21
  22. 22. Protocols and Networks in the TCP/IP Model Initially Layer (OSI names) TELNET FTP SMTP DNS ApplicationProtocols TCP Transport UDP IP Network SATNET PACKET LAN Physical +Networks ARPANET RADIO Data link Fig .3 22
  23. 23. Application Layer• TCP/IP model does not have session or presentation layers• On top of the transport layer is the application layer• It contains all the higher-level protocols• The early ones included virtual terminal (TELNET), file transfer (FTP), and electronic mail (SMTP)• TELNET, the virtual terminal protocol allows a user on one machine to log into a distant machine and work there 23
  24. 24. Application Layer (Contd….)• The file transfer protocol provides a way to move data in the form of files efficiently from one machine to another• SMTP (Simple Mail Transfer Protocol) also called as Electronic mail• It was originally just a kind of file transfer, later a specialized protocol was developed for it• Domain Name Service (DNS) for mapping host names onto their network addresses 24
  25. 25. Application Layer (Contd….)•Hyper Text Transfer Protocol (HTTP), the protocol usedfor fetching pages on the World Wide Web•DNS is used to translate the email ID into IP address.Users can identify themselves through email ID •Network News Transfer Protocol (NNTP) the protocolused for moving news articles, which will be used by thenews paper companies 25
  26. 26. Summary In this class, you have learnt about• Functions of various layers in TCP/IP• The various protocols used in TCP/IP along with their importance• The TCP/IP architecture and its functions 26
  27. 27. Quiz1) This layer deals with the physical transmission medium a) Host-to-Network b) Internet layer c) Transport layer d) Application layer 27
  28. 28. Quiz2) TCP protocol is related to which layer a) Host-to-Network b) Internet layer c) Transport layer d) Application layer 28
  29. 29. Quiz3) UDP protocol is related to which layer a) Host-to-Network b) Internet layer c) Transport layer d) Application layer 29
  30. 30. Quiz4) IP protocol is related to which layer a) Host-to-Network b) Internet layer c) Transport layer d) Application layer 30
  31. 31. Quiz5) WWW can be accessed using this protocol a) IP b) UDP c) HTTP d) NNTP 31
  32. 32. Quiz6) News publishing companies use this protocol a) IP b) UDP c) HTTP d) NNTP 32
  33. 33. Quiz7) E-mail is supported by this protocol a) IP b) SMTP c) HTTP d) NNTP 33
  34. 34. Quiz8) Traffic congestion is the function of this layer a) Host-to-Network b) Internet layer c) Transport layer d) Application layer 34
  35. 35. Frequently Asked QuestionsShort Questions1. Name the various layers of TCP/IP architecture ?2. What are the functions performed by Host-to-Network layer?3. What are the functions performed by Internet layer ?4. What are the functions performed by Transport layer ? 35
  36. 36. Frequently Asked Questions5. What are the functions performed by Application layer ?6. What are the various protocols supported by TCP/IP architecture ?7. Briefly describe about TCP and UDP ? 36
  37. 37. Essay Questions1. Discuss in detail about TCP/IP architecture and explain the functions performed by different layers ?2. Discuss about all the types of protocols supported by TCP/IP network architecture model ? 37