1 / 38

Data and Computer Communications

Data and Computer Communications. Chapter 2 – Protocol Architecture, TCP/IP, and Internet-Based Applications. Protocol Architecture, TCP/IP, and Internet-Based Applications.

briar
Download Presentation

Data and Computer Communications

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Data and Computer Communications Chapter 2 – Protocol Architecture, TCP/IP, and Internet-Based Applications

  2. Protocol Architecture, TCP/IP, and Internet-Based Applications • To destroy communication completely, there must be no rules in common between transmitter and receiver—neither of alphabet nor of syntax —On Human Communication, Colin Cherry

  3. Need For Protocol Architecture • data exchange can involve complex procedures, cf. file transfer example • better if task broken into subtasks • implemented separately in layers in stack • each layer provides functions needed to perform communication for layers above • using functions provided by layers below • peer layers communicate with a protocol

  4. Key Elements of a Protocol • syntax – data block format • semantics - control info. & error handling • timing - speed matching & sequencing

  5. TCP/IP Protocol Architecture • developed by US Defense Advanced Research Project Agency (DARPA) • for ARPANET packet switched network • used by the global Internet • protocol suite comprises a large collection of standardized protocols

  6. Simplified Network Architecture

  7. TCP/IP Layers • no official model but a working one • Application layer • Host-to-host, or transport layer • Internet layer • Network access layer • Physical layer

  8. Physical Layer • concerned with physical interface between computer and network • concerned with issues like: • characteristics of transmission medium • signal levels and nature • data rates • other related matters

  9. Network Access Layer • exchange of data between an end system and attached network • concerned with issues like : • destination address provision • invoking specific services like priority • access to & routing data across a network link between two attached systems • allows layers above to ignore link specifics

  10. Internet Layer (IP) • routing functions across multiple networks • for systems attached to different networks • using IP protocol • implemented in end systems and routers • routers connect two networks and relays data between them

  11. Transport Layer (TCP) • common layer shared by all applications • provides reliable delivery of data • in same order as sent • commonly uses TCP

  12. Application Layer • provide support for user applications • need a separate module specific for each type of application

  13. Operation of TCP and IP

  14. Addressing Requirements • two levels of addressing required • each host on a subnet needs a unique global network address • its IP address • each application on a (multi-tasking) host needs a unique address within the host • known as a port

  15. Operation of TCP/IP

  16. Transmission Control Protocol (TCP) • usual transport layer is (TCP) • provides a reliable connection for transfer of data between applications • a TCP segment is the basic protocol unit • TCP tracks segments between entities for duration of each connection

  17. TCP Header

  18. User Datagram Protocol(UDP) • an alternative to TCP • no guaranteed delivery • no preservation of sequence • no protection against duplication • minimum overhead • Just adds port addressing to IP

  19. UDP Header

  20. IP Header

  21. IPv6 Header

  22. TCP/IP Applications • have a number of standard TCP/IP applications such as • Simple Mail Transfer Protocol (SMTP) • File Transfer Protocol (FTP) – control and data connections • Telnet

  23. Some TCP/IP Protocols

  24. OSI • Open Systems Interconnection • developed by the International Organization for Standardization (ISO) • has seven layers – too many • is a theoretical system delivered too late! • TCP/IP is the de facto standard

  25. OSI Layers

  26. OSI v TCP/IP

  27. Standardized Protocol Architectures

  28. Layer Specific Standards

  29. Service Primitives and Parameters • define services between adjacent layers using: • primitives to specify function performed • parameters to pass data and control info

  30. Primitive Types

  31. Traditional vs Multimedia Applications • traditionally Internet dominated by info retrieval applications • typically using text and image transfer • E.g. email, file transfer, web • see increasing growth in multimedia applications • involving massive amounts of data • such as streaming audio and video

  32. Elastic and Inelastic Traffic • elastic traffic • can adjust to delay & throughput changes over a wide range • E.g. traditional “data” style TCP/IP traffic • some applications more sensitive though • inelastic traffic • does not adapt to such changes • E.g. “real-time” voice & video traffic • need minimum requirements on net arch

  33. Multimedia Taxonomy

  34. Summary • introduced need for protocol architecture • TCP/IP protocol architecture • OSI Model & protocol architecture standardization • traditional vs multimedia application needs

  35. MCQ The process to process delivery of the entire message is the responsibility of the Network/Transport/Application/Physical layer. As the data packet moves from the lower to the upper layers, headers are added/subtracted/rearranged/modified. Following is an application layer service. Remote log-in/file transfer/mail service/all of the above

  36. MCQ Match the following with one of the five internet layers. Communicates directly with user application program Error correction and retransmission Mechanical, electrical, and functional interface Reassembly of data packets

  37. Problems • Q1. In a protocol suite, layer N is above layer (N-1). • In the case of segmentation, is it necessary that each (N-1) level segment contain a copy of the level N-header? Why? • Blocking means combining several level N PDUs into one (N-1) level PDU. In the case of blocking, is it necessary that each level- N PDU retain its own header? Why?

  38. Problems • Q2. A TCP segment of 1500 bit data and 160 bit header is sent to the IP layer. IP layer adds 160 bit header. It is then transmitted through a network which uses 24-bit packet header. The destination network can accept packet size of 800 bits. How many bits (including header) are delivered to the destination network layer?

More Related