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© 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Chapter 7: Transport Layer Introduction to Networking.

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Presentation on theme: "© 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Chapter 7: Transport Layer Introduction to Networking."— Presentation transcript:

1 © 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Chapter 7: Transport Layer Introduction to Networking

2 Presentation_ID 2 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Chapter 7 7.1 Transport Layer Protocols 7.2 TCP and UDP 7.3 Summary

3 Presentation_ID 3 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Chapter 7: Objectives  Describe the purpose of the transport layer in managing the transportation of data in end-to-end communication.  Describe characteristics of the TCP and UDP protocols, including port numbers and their uses.  Explain how TCP session establishment and termination processes facilitate reliable communication.  Explain how TCP protocol data units are transmitted and acknowledged to guarantee delivery.  Explain the UDP client processes to establish communication with a server.  Determine whether high-reliability TCP transmissions, or non- guaranteed UDP transmissions, are best suited for common applications.

4 Presentation_ID 4 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Role of the Transport Layer 7.0

5 Presentation_ID 5 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Transportation of Data Role of the Transport Layer The Transport Layer is responsible for establishing a temporary communication session between two applications and delivering data between them. TCP/IP uses two protocols to achieve this:  Transmission Control Protocol (TCP)  User Datagram Protocol (UDP) Primary Responsibilities of Transport layer Protocols  Tracking the individual communication between applications on the source and destination hosts  Segmenting data for manageability and reassembling segmented data into streams of application data at the destination  Identifying the proper application for each communication stream 7.0.1.1, 7.0.1.2 Consider doing the talking game on 7.0.1.2

6 Presentation_ID 6 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Transportation of Data Enabling Applications to Communicate The primary responsibilities of transport layer protocols are:  Tracking the individual communication between applications on the source and destination hosts  Segmenting data for manageability and reassembling segmented data into streams of application data at the destination  Identifying the proper application for each communication stream 7.1.1.1. 7.1.1.2 Do buttons on 7.1.1.2

7 Presentation_ID 7 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Transportation of Data Conversation Multiplexing Segmenting the data  Enables many different communications, from many different users, to be interleaved (multiplexed) on the same network, at the same time.  Provides the means to both send and receive data when running multiple applications.  Header added to each segment to identify it. 7.1.1.3

8 Presentation_ID 8 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Transportation of Data Transport Layer Reliability Different applications have different transport reliability requirements TCP/IP provides two transport layer protocols, TCP and UDP Transmission Control Protocol (TCP)  Provides reliable delivery ensuring that all of the data arrives at the destination.  Uses acknowledged delivery and other processes to ensure delivery  Makes larger demands on the network – more overhead User Datagram Protocol (UDP)  Provides just the basic functions for delivery – no reliability  Less overhead TCP or UDP  There is a trade-off between the value of reliability and the burden it places on the network.  Application developers choose the transport protocol based on the requirements of their applications. 7.1.1.3 7.1.1.4

9 Presentation_ID 9 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Transportation of Data TCP With TCP, the three basic operations of reliability are:  Tracking transmitted data segments  Acknowledging received data  Retransmitting any unacknowledged data 7.1.1.5 Do animation on 7.1.1.5

10 Presentation_ID 10 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Transportation of Data UDP  UDP provides just the basic functions for delivering data segments between the appropriate applications, with very little overhead and data checking.  UDP is known as a best- effort delivery protocol.  There is no acknowledgement that the data is received at the destination. 7.1.1.6 Do animation on 7.1.1.6

11 Presentation_ID 11 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Transportation of Data Compare TCP and UDP 7.1.1.7

12 Presentation_ID 12 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Transportation of Data 7.1.1.8 Activity - TCP, UDP or Both 7.1.1.8 Do Activity 7.1.1.8 in class

13 Presentation_ID 13 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Introducing TCP and UDP Introducing TCP Transmission Control Protocol (TCP)  RFC 793  Connection-oriented – creating a session between source and destination  Reliable delivery – retransmitting lost or corrupt data  Ordered data reconstruction – numbering and sequencing of segments  Flow control - regulating the amount of data transmitted  Stateful protocol – keeping track of the session 7.1.2.1

14 Presentation_ID 14 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Transportation of Data 7.1.2.2 Role of TCP 7.1.2.2 Briefly Discuss: Ports Sequence numbers Ack numbers

15 Presentation_ID 15 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Introducing TCP and UDP Introducing UDP User Datagram Protocol (UDP)  RFC 768  Connectionless  Unreliable delivery  No ordered data reconstruction  No flow control  Stateless protocol Applications that use UDP:  Domain Name System (DNS)  Video Streaming  Voice over IP (VoIP) 7.1.2.3

16 Presentation_ID 16 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Transportation of Data 7.1.2.4 Role of UDP 7.1.2.4 Discuss: Ports Also Note: No Sequence numbers No Ack numbers

17 Presentation_ID 17 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Introducing TCP and UDP Separating Multiple Communications Port Numbers are used by TCP and UDP to differentiate between applications.. 7.1.2.5, 7.1.2.6

18 Presentation_ID 18 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Introducing TCP and UDP TCP and UDP Port Addressing 7.1.2.7 We are Seeing the whole picture now

19 Presentation_ID 19 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Introducing TCP and UDP TCP and UDP Port Addressing 7.1.2.8, 7.1.2.9 Know the 3 types of ports Start memorizing well know port numbers Do buttons on 7.1.2.8

20 Presentation_ID 20 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Introducing TCP and UDP TCP and UDP Port Addressing Netstat  Used to examine TCP connections that are open and running on a networked host 7.1.2.9 Do buttons on 7.1.2.9

21 Presentation_ID 21 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Introducing TCP and UDP TCP and UDP Segmentation 7.1.2.10 Know differences in UPD and TCP

22 Presentation_ID 22 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Transportation of Data 7.1.2.11 Activity - Compare TCP and UDP Characteristics 7.1.1.8 Do Activity 7.1.2.11 in class

23 Presentation_ID 23 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP Communication TCP Server Processes 7.2.1.1 Do Animation on 7.2.1.1 in class

24 Presentation_ID 24 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP Communication TCP Server Processes 7.2.1.2 Do Buttons on 7.2.1.2 in class

25 Presentation_ID 25 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP Communication TCP Connection, Establishment and Termination Three-Way Handshake  Establishes that the destination device is present on the network.  Verifies that the destination device has an active service and is accepting requests on the destination port number that the initiating client intends to use for the session.  Informs the destination device that the source client intends to establish a communication session on that port number. 7.2.1.3 Know the three way handshake !!!

26 Presentation_ID 26 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP Communication TCP Connection, Establishment and Termination 7.2.1.3 Do the buttons on 7.2.1.3 Know the three way handshake !!!

27 Presentation_ID 27 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP Communication NEED New Graphic for this and next two slides TCP Three-Way Handshake – Step 1  Step 1: The initiating client requests a client-to- server communication session with the server. 7.2.1.4

28 Presentation_ID 28 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP Communication TCP Three-Way Handshake – Step 2  Step 2: The server acknowledges the client-to- server communication session and requests a server-to-client communication session. 7.2.1.5

29 Presentation_ID 29 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP Communication TCP Three-Way Handshake – Step 3  Step 3: The initiating client acknowledges the server-to-client communication session. 7.2.1.6

30 Presentation_ID 30 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP Communication TCP Session Termination 7.2.1.7 Do the buttons on 7.2.1.7 For both Establish and Terminate of a TCP connection

31 Presentation_ID 31 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Transportation of Data 7.2.1.9 Activity - TCP Connection and Termination Process 7.2.1.9 Do Activity 7.2.1.9 in class

32 Presentation_ID 32 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Reliability and Flow Control TCP Reliability – Ordered Delivery Sequence numbers used to reassemble segments into original order 7.2.2.1

33 Presentation_ID 33 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP Reliability – Acknowledgement and Window Size The sequence number and acknowledgement number are used together to confirm receipt. Window Size - The amount of data that a source can transmit before an acknowledgement must be received. 7.2.2.2

34 Presentation_ID 34 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP Reliability and Flow Control TCP Reliability - Data Loss and Retransmission 7.2.2.3 Do animation on 7.2.2.3 in class

35 Presentation_ID 35 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP Reliability and Flow Control Window Size and Acknowledgements 7.2.2.4

36 Presentation_ID 36 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Reliability and Flow Control TCP Flow Control – Congestion Avoidance 7.2.2.5

37 Presentation_ID 37 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Reliability and Flow Control TCP Reliability - Acknowledgements 7.2.2.5

38 Presentation_ID 38 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UDP Communication UDP Low Overhead vs. Reliability UDP  Simple protocol that provides the basic transport layer functions  Used by applications that can tolerate small loss of data  Used by applications that cannot tolerate delay Used by  Domain Name System (DNS)  Simple Network Management Protocol (SNMP)  Dynamic Host Configuration Protocol (DHCP)  Trivial File Transfer Protocol (TFTP)  IP telephony or Voice over IP (VoIP)  Online games 7.2.3.1

39 Presentation_ID 39 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UDP Communication Datagram Reassembly 7.2.3.2

40 Presentation_ID 40 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UDP Communication UDP Server and Client Processes  UDP-based server applications are assigned well- known or registered port numbers.  UDP client process randomly selects port number from range of dynamic port numbers as the source port. 7.2.3.3

41 Presentation_ID 41 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential UDP Communication UDP Server and Client Processes 7.2.3.4 Do buttons on 7.2.3.4 in class

42 Presentation_ID 42 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP or UDP Applications that use TCP 7.2.4.1

43 Presentation_ID 43 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential TCP or UDP Applications that use UDP 7.2.4.2

44 Presentation_ID 44 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential Chapter 7: Summary  The role of the Transport layer is to provide three main functions: multiplexing, segmentation and reassembly, and error checking.  These functions are necessary in order to address issues in quality of service and security on networks.  Knowing how TCP and UDP operate and which popular applications use each protocol will allow the implementation of quality of service and build more reliable networks.  Ports provide a “tunnel” for data to get from the Transport layer to the appropriate application at the destination. 7.3.1.1

45 Presentation_ID 45 © 2008 Cisco Systems, Inc. All rights reserved.Cisco Confidential


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