CSC 600 Internetworking with TCP/IP

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CSC 600 Internetworking withTCP/IP

• Unit 1 Introduction
• (Ch. 1, 11)
• Dr. Cheer-Sun Yang
• Spring 2001

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What is communication and networking ?

• Communication Different machines, (which are
  also referred to as hosts, communication
  entities, or stations), running different
  operating systems transferring text, voice, image
  data between them.
• Networking the communication entities being
  connected together indirectly via another
  communication entity or entities. This results in
  a communication network.

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Motivation for Networking

• Different machines, (which are also referred to
  as hosts, communication entities, or stations),
  running different operating systems need to
  communicate.
• Computer users need to exchange data.
• Users need to access information stored remotely.

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What is internetworking?

• The technology, called internetworking,
  accommodates multiple, diverse underlying
  hardware technologies by providing a way to
  interconnect heterogeneous networks and a set of
  communication conventions that makes them
  interoperate.
• Internetworking provides hardware and software
  techniques and protocols for interconnecting
  heterogeneous networks.

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Communication Protocols

• Communication is achieved through the cooperation
  of hardware and software.
• Two parties engaged in communication must comply
  with a set of rules which governing the timing of
  exchanging messages, the message format, the
  meaning of each message content.
• Protocol a set of rules which governs the
  exchange of information.
• For example, TCP is a protocol, IP is another.

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Types of Computer Networking Systems

• Intranetworkinga communication system for
  connecting homogeneous networks together.
• Internetworkinga communication system for
  connecting heterogeneous networks together.

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Internetworking vs. the Internet

• Internetworkingthe communication of
  heterogeneous computers.
• Interneta specific kind of network system.

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The Internet

• U.S Government agencies realized the
  importance and potential of internetworking
  technology many years ago, and have funded
  research that has made possible a global
  Internet.
• An example of Open System Interconnection.

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Open vs. Proprietary

• Open Systems the specifications are
• publicly available supported by almost all
  
• venders
• Proprietary Systems only supported by
• specific venders. For example, IBMs
• SNA, APPLEs AppleTalk, Datapoints
• ARCNet.

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Internet Services

• Application-Level Internet Services
• World Wide Web
• Electronic mail
• File transfer
• Remote login (telnet)
• Voice on IP Internet Telephony
• Videoconferencing using Internet to transmit
  text, image, and voice data.
• Mobile IP accessing Internet from within a car

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Internet Services(contd)

• Network-Level Internet Services
• Connectionless Packet Delivery Service
• Reliable Stream Transport Service

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Summary of Internet Services

• Each layer provides services to the layer above
  it.
• Each layer uses the services provided by the
  layer below it.
• This resulting protocol architecture is called a
  protocol stack.

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Application Layer Services

• Virtual Terminal
• File Transfer
• Remote Login or Telnet
• E-mail
• World Wide Web

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Transport-Level Services

• Connectionless Packet Delivery Services
• Reliable Connection-oriented Stream Transport
  Service
• Provided by TCP and UDP, respectively

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Network-Level Services

• Connectionless Packet Delivery Services
• Fragmentation and Assemble
• Provided by Internetworking Protocol(IP) software

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Media Access-Level Services

• Framing of data bit streams
• Error detection and recovery
• Could be implemented in the NIC.
• The driver implements some device accessing
  functions for IP software to use.

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Why is so special about the Internet?

• Network technology independence Although TCP/IP
  is based on conventional packet switching
  technology, it is independent of any particular
  venders hardware. In contrast, SNA only runs on
  IBM hardware.
• Universal Interconnection IP address identifies
  a host from another.

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Why is so special about Internet?(contd)

• End-to-end acknowledgements The TCP/IP protocols
  only provide acknowledgements between the source
  and the destination instead of between successive
  machines along the path. In contrast, X.25
  provides acknowledgements between any two nodes.
• Application Protocol Standards.

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History of the Internet

• Late 60sThe government-funded Advanced Research
  Projects Agency(DARPA) created ARPANET in 1969.
• Mid 1970s ARPA began to work on connecting
  computers in all associated agencies. The early
  Internet had emerged.

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History of the Internet(contd)

• 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.

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Other Names of the Internet

• ARPANET the U.S. Department of Defense Advanced
  Research Projects (ARPA)
• The TCP/IP Internet
• The (Global) Internet

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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, a reorg of the Internet Advisory
  Board (IAB) occurred in 1986. Now, there is an
  Internet Engineering Task Force (IETF) and
  Internet Research Task Force (IRTF) 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).

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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

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Standards Organizations

• ISO (International Organization for
  Standardization)
• Internet Architecture Board (IAB)
• ITU-T (formally CCITT)
• ATM forum

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Internet Standards Organizations

• Internet Activities Board (IAB) 1983
• Internet Research Task Force (IRTF)
• Internet Engineering Task Force (IETF)
• Internet Society replaced IAB around 1992.

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Request For Comments(RFCs)

• Documentation of work on the Internet, proposals
  for new or revised protocols, and TCP/IP protocol
  standards all appear in a series of technical
  reports called Internet Request For
  Comments(RFCs).
• Please check my Web Page for accessing RFCs.
• TCP RFC 793
• UDP RFC 768
• IP 791, 760

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The Internet Now

• In 1992, as the Internet moved away from the U.S.
  government roots, a society was formed to
  encourage participation in the Internet. A new
  organization called Internet Society (ISOC)
  becomes the host \for the IAB.
• Explosive growth
• 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
• (END OF CHAPTER 1)

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Chapter 11Protocol Layering

• Open Systems vs. closed systems
• SNA vs. TCP/IP

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The Need of Multiple Protocols

• Open Systems vs. closed systems
• SNA vs. TCP/IP

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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.

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Connecting Two PCs

• Applications run on top of OS with communication
  software implemented in it.
• Operating system communicates with network driver
  that is another software.
• Network driver talks to communication hardware
  including Network Interface Card (NIC) and modem.

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Connecting Two PCs(contd)

• Both parties must agree on the format of the data
  unit being exchanged.
• Both parties must agree on how to initiate the
  connection and when the send and receive
  operations can be conducted.
• When to disconnect and how.

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Keys

• Both parties must use the same data format.
• Both parties must see eye to eye on the meaning
  of the content.
• Both must agree on the timing for exchanging
  information.
• The three factors constitute the core of a set
  of rules which is called a communication protocol.

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Communication Protocol

• Definition all parties involved involved in the
  communication must comply with a set of rules
  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

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Key Elements of a Protocol

• Syntax
• Data formats
• Signal levels
• Semantics
• Control information
• Error handling
• Timing
• Speed matching
• Sequencing

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Comm. software
device driver
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Communication Reference Models

• In summary, we need a communication reference
  model to describe the relationship between
  various software and hardware.
• There are two well-known reference models TCP/IP
  and OSI.
• A reference model describes the layering
  relationship of software and hardware involved in
  the communication.
• Lets take a look at TCP/IP model.

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The Need for Layered Protocols

• Complex data communication systems do not use a
  single protocol to handle all transmission tasks.
• The require a set of cooperative protocols,
  sometimes called a protocol family or protocol
  suite..

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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

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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.

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Network Access Layer

• Exchange of data between end system and network
• Destination address provision
• Invoking services like priority

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Internet Layer (IP)

• Systems may be attached to different networks
• Routing functions across multiple networks
• Implemented in end systems and routers

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Transport Layer (TCP)

• Reliable delivery of data
• Ordering of delivery

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Application Layer

• Support for user applications
• e.g. http, SMPT

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TCP/IP Protocol Architecture Model
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Protocol Data Unit (PDU)

• An OSI term for the smallest data unit each layer
  handles.
• TCP/IP terms are
• Data link layer data frame
• IP Layer IP datagram
• TCP segment (p. 223) or TCP packet(p 184)
• UDP datagram
• Usually, datagram is used with connectionless
  service packet is used with connection-oriented
  service.

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Layering Principle

• Layered protocols are designed so that layer n
  at the destination receives exactly the same
  object sent by layer n at the source.

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Layering in a Point-to-Point Network
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Layering in a TCP/IP Internet Environment
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Layering in the Presence of Network Substructure
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Two Important Boundaries in the TCP/IP Model
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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

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OSI Layers

• Application
• Presentation
• Session
• Transport
• Network
• Data Link
• Physical

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Physical Layer

• Corresponds to basic hardware.
• Example NIC, modem, cable
• Topics include transmission media, error
  detection, correction.

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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,
  flow control.

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Network Layer

• Specifies how to assign addresses and how to
  forward packets to its destination.
• Detail topics include the format of a data frame,
  flow control.

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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.

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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.

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Presentation Layer

• Controls the encoding and decoding of data.

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Application Layer

• Controls the interface with users.
• Application, presentation, session layers are
  usually implemented together instead of using
  laying architecture.

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Nested Protocol Headers
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Disadvantage of Layering

• The software that results from strict layering
  can be extremely inefficient.
• The TCP layer will not understand the format of
  the IP datagram.
• The TCP layer will not know how the network will
  route the datagram.
• The packet size cannot be optimized.

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WHAT IS THIS?
Comm. software
device driver
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Whats Next? TCP/IP Over What?

• Two issues
• Medium and connection
• Hardware addressing
• But..

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When is he going to stop?
Do I really need CSC600?
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Reading Assignment

• Chapters 1, 2, 3, 11 (ignore 2.5, 2.6, 2.10,
  2.11)