Introduction to Networking

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Introduction to Networking

• STBS 2201
• By
• Norrima Mokhtar

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STBS 2201Pengenalan Kepada Networking

• Tajuk
• Introduction to NetworkingNetworking The Big
  PictureTelecommunications Components of The Big
  PictureISO/OSI
• Breaking Up the Big Picture!The Local LoopLocal
  Area Networks (LANS)MANsWANs

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Tajuk

• Transmission Media - Guided
• Open Wire
• Twisted Pair
• Unshielded Twisted Pair
• Coaxial Cable
• Optical fiber
• Optical Transmission Modes
• Step Index Mode
• Graded Index Mode
• Single Mode
• Advantages of Optical Fiber
• Disadvantages of optical fiber
• Media versus Bandwidth
• Transmission Media - Unguided

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Tajuk

• Introduction to TCP/IPLink http//www.yale.edu/pcl
  t/COMM/TCPIP.HTM
• Introduction to the services.
• Network Interface Cards
• Repeaters
• Hubs
• Bridges
• Routers
• Gateways
• And is good if this will be added.
• Domain Name Service
• FTP Service
• HTTP service And others services provided.

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Data Communications

• Is transfer of data or information between a
  source and a receiver.
• The source transmits the data and the receiver
  receives it. Data Communication is interested in
  the transfer of data, the method of transfer and
  the preservation of the data during the transfer
  process.
• The purpose of data communications is to provide
  the rules and regulations that allow computers
  with different disk operating systems, languages,
  cabling and locations to share resources.
• The rules and regulations are called protocols
  and standards in data communications.

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Definition of NETWORK

• A network is a set of hardware devices connected
  together, either physically or logically to allow
  them to exchange information
• When two or more computers are connected
  together, they are in a network. The practice of
  connecting these computers together is called
  networking.

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NETWORK

• A network may contain two or more computers that
  are linked to share resources, files, and / or to
  communicate. To achieve communicating, commuters
  on a network must have a common protocol.
• Different organizations and institutions require
  different types of network infrastructure,
  protocols and applications. This will depend on
  the size of the organization, the level of
  security required, the  type of business, level
  of administrative support available,  the amount
  of network traffic, needs of the network users
  the network budget.
• The type of network used will determine its size
  and the number of computers connected as well as
  the physical distance that could be covered by
  the network.

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What does networking have to do with telephones?

• Telephones and networking work hand in hand.
• The telecommunications industry has been
  gradually integrating with the computer industry
  and the computer industry has been gradually
  integrating with the telecommunications industry.
  
• The common goal is to join distantly located
  Local Area Networks into Metropolitan and Wide
  Area Networks (MANs and WANs).

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Voice Channels

• When we think of telecommunications, the first
  thing that comes to mind is telephone systems and
  the phone at home.
• Talking to someone on the phone uses voice
  channels.
• Voice Channel Dial-up connection through a modem
  using standard telephone lines.
• Typical voice channel communication rates are
  300, 1200, 2400, 9600, 14.4k, 19.2k, 28.8k, 33.6k
  and 56 kbps (bits per second).

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Data Channels

• Data channels are dedicated lines for
  communicating digitized voice and data.
• At the end of 1996, there was a major milestone
  when more data was communicated in North
  America's telecommunications system than voice.
• Data Channels are special communications channels
  provided by "common carriers" such as Telus,
  Sprint, Bell Canada, ATT, etc. for transferring
  digital data.
• Data Channels are also called "Leased Lines".
  They are "directly" connected you don't have to
  dial a connection number. The connections are up
  and running 24 hours per day. They appear to work
  as if there were a wire running directly between
  the source and the destination. Typical transfer
  rates for data channels are 56 k, 128k, 1.544 M,
  2.08 M, 45M and 155 Mbps. (In Malaysia depends on
  package offer by service provider such as TMNET)

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Data Channels

• Common carriers charge for data connections by
• The amount of data transferred (megabytes per
  month)
• The transfer rate (bits per second)
• The amount of use (time per month)

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Applications

• Networks are used for an incredible array of
  different purposes. In fact, the definitions
  above are so simple for the specific reason that
  networks can be used so broadly, and can allow
  such a wide variety of tasks to be accomplished.
  While most people learning about networking focus
  on the interconnection of PCs and other true
  computers, actually we use various types of
  networks every day.

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Networking The Big Picture
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Telecommunications Components of The Big Picture

• ISDN Integrated Services Digital Network
• Private Branch Exchanges PBXs, Key Systems
• Telcos ATT, Bell Telephone, Sprint, Telus
• DataPac DataRoute Packet switching and analog
  switching WAN protocols
• Cell Relay Digital packet switching WAN
  protocol
• Frame Relay Digital packet switching WAN
  protocol
• X.25 Analog packet switching WAN protocol
• ATM Asynchronous Transfer Mode WAN protocol
• World Wide Web Hypertext-based multimedia
  system
• ADSL Asymmetrical Digital Subscriber Line

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Applications

• Example
• Each time you pick up a phone
• Use a credit card at a store
• Get cash from an ATM machine
• Even plug in an electrical appliance
• we are using some type of network.

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Computer Networks

• A is a set of independent computer systems
  interconnected by telecommunication links.

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The Advantages (Benefits) of Networking

• Connectivity and Communication
• Data Sharing
• Hardware Sharing
• Internet Access
• Internet Access Sharing
• Data Security and Management
• Performance Enhancement and Balancing
• Entertainment

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Connectivity and communication

• Networks connect computers and the users of those
  computers. Individuals within a building or work
  group can be connected into local area networks
  (LANs) LANs in distant locations can be
  interconnected into larger wide area networks
  (WANs).
• Once connected, it is possible for network users
  to communicate with each other using technologies
  such as electronic mail. This makes the
  transmission of business (or non-business)
  information easier, more efficient and less
  expensive than it would be without the network.

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Data Sharing

• One of the most important uses of networking is
  to allow the sharing of data. Before networking
  was common, an accounting employee who wanted to
  prepare a report for her manager would have to
  produce it on his PC, put it on a floppy disk,
  and then walk it over to the manager, who would
  transfer the data to her PC's hard disk.
• True networking allows thousands of employees to
  share data much more easily and quickly than
  this. More so, it makes possible applications
  that rely on the ability of many people to access
  and share the same data, such as databases.

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Hardware Sharing

• Networks facilitate the sharing of hardware
  devices.
• For example, instead of giving each of 10
  employees in a department an expensive color
  printer, one printer can be placed on the network
  for everyone to share.

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Internet Access

• The Internet is itself an enormous network, so
  whenever you access the Internet, you are using a
  network.
• The significance of the Internet on modern
  society is hard to exaggerate, especially for
  those of us in technical fields.

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Internet Access Sharing

• Small computer networks allow multiple users to
  share a single Internet connection.
• Special hardware devices allow the bandwidth of
  the connection to be easily allocated to various
  individuals as they need it, and permit an
  organization to purchase one high-speed
  connection instead of many slower ones.

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Data Security and Management

• In a business environment, a network allows the
  administrators to much better manage the
  company's critical data. Instead of having this
  data spread over dozens or even hundreds of small
  computers in a haphazard fashion as their users
  create it, data can be centralized on shared
  servers.
• This makes it easy for everyone to find the data,
  makes it possible for the administrators to
  ensure that the data is regularly backed up, and
  also allows for the implementation of security
  measures to control who can read or change
  various pieces of critical information.

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Performance Enhancement and Balancing

• Under some circumstances, a network can be used
  to enhance the overall performance of some
  applications by distributing the computation
  tasks to various computers on the network.

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Entertainment

• Networks facilitate many types of games and
  entertainment. The Internet itself offers many
  sources of entertainment, of course.
• In addition, many multi-player games exist that
  operate over a local area network. Many home
  networks are set up for this reason, and gaming
  across wide area networks (including the
  Internet) has also become quite popular.
• Of course, if you are running a business and have
  easily-amused employees, you might insist that
  this is really a disadvantage of networking and
  not an advantage!

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The Disadvantages (Costs) of Networking

• Network Hardware, Software and Setup Costs
• Hardware and Software Management and
  Administration Costs
• Undesirable Sharing
• Data Security Concerns

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Network Hardware, Software and Setup Costs

• Computers don't just magically network
  themselves, of course. Setting up a network
  requires an investment in hardware and software,
  as well as funds for planning, designing and
  implementing the network.
• For a home with a small network of two or three
  PCs, this is relatively inexpensive, possibly
  amounting to less than a hundred dollars with
  today's low prices for network hardware, and
  operating systems already designed for networks.
• For a large company, cost can easily run into
  tens of thousands of RM or more.

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Hardware and Software Management and
Administration Costs

• In all but the smallest of implementations,
  ongoing maintenance and management of the network
  requires the care and attention of an IT
  professional.
• In a smaller organization that already has a
  system administrator, a network may fall within
  this person's job responsibilities, but it will
  take time away from other tasks.
• In more substantial organizations, a network
  administrator may need to be hired, and in large
  companies an entire department may be necessary.

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Undesirable Sharing

• With the good comes the bad while networking
  allows the easy sharing of useful information, it
  also allows the sharing of undesirable data.
• One significant sharing problem in this regard
  has to do with viruses, which are easily spread
  over networks and the Internet.
• Mitigating these effects costs more time, money
  and administrative effort.

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Illegal or Undesirable Behavior

• Similar to the point above, networking
  facilitates useful connectivity and
  communication, but also brings difficulties with
  it.
• Typical problems include abuse of company
  resources, distractions that reduce productivity,
  downloading of illegal or illicit materials, and
  even software piracy.
• In larger organizations, these issues must be
  managed through explicit policies and monitoring,
  which again, further increases management costs.

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Data Security Concerns

• If a network is implemented properly, it is
  possible to greatly improve the security of
  important data.
• In contrast, a poorly-secured network puts
  critical data at risk, exposing it to the
  potential problems associated with hackers,
  unauthorized access and even sabotage.

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Networking is worthwhile

• Most of these costs and potential problems can be
  managed that's a big part of the job of those
  who set up and run networks.
• In the end, as with any other decision, whether
  to network or not is a matter of weighing the
  advantages against the disadvantages.
• Of course today, nearly everyone decides that
  networking is worthwhile.

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Networking is worthwhile

• Networking has a few drawbacks that balance
  against its many positive aspects. Setting up a
  network has costs in hardware, software,
  maintenance and administration.
• It is also necessary to manage a network to keep
  it running smoothly, and to address possible
  misuse or abuse.
• Data security also becomes a much bigger concern
  when computers are connected together.

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ISO/OSI

• Compatible interconnection of network devices is
  fundamental to reliable network communications.
  Developing a set of standards that equipment
  manufacturers could adhere to went a long way
  towards providing an open environment for network
  communications.

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ISO/OSI

• In the late 1970s the International Organization
  for Standardization (ISO) worked on a seven layer
  model for LAN architectures by defining the Open
  Systems Interconnection Basic Reference Model
  (OSI).
• Alongside this The ISO developed a set of
  protocols that fit within this model.
• Since then, other models such as the 5 layer
  TCP(Transmission Control Protocol )/IP model were
  developed, however the OSI model is still used to
  map and categorise protocols because of its
  concise and clear way of representing network
  functions.

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These are the 7 Layers of the OSI model

• 7. Application Layer (Top Layer)
• 6. Presentation Layer
• 5. Session Layer
• 4. Transport Layer
• 3. Network Layer
• 2. Data Link Layer
• 1. Physical Layer (Bottom Layer)

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Application Layer 7

• The application layer defines the interfaces for
  communication and data transfer.
• This layer also provides and support services
  such as job transfer, handles network access,
  e-mail, supports user applications and error
  recovery.

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Application Layer 7

• Examples of services within the application layer
  include
• FTP (File Transfer Protocol),
• DNS
• (The Domain Name System (abbreviated DNS) is an
  Internet directory service )
• SNMP
• Simple Network Management Protocol (SNMP)
• SMTP gateways
• Simple Mail Transfer Protocol (SMTP)
• Web browser
• Network File System (NFS)
• Telnet and Remote Login (rlogin)
• Database software
• Print Server Software

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Presentation Layer 6

• This provides function call exchange between host
  operating systems and software layers. It defines
  the format of data being sent and any encryption
  that may be used, and makes it presentable to the
  Application layer.
• Examples of services used are listed below
• MIDI
• MIDI (Musical Instrument Digital Interface) is an
  industry-standard protocol that enables
  electronic musical instruments, computers and
  other equipment to communicate, control and
  synchronize with each other.
• HTML
• Hypertext Markup Language, is the predominant
  markup language for web pages.

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Presentation Layer 6

• Examples of services used are listed below
• GIF
• The Graphics Interchange Format (GIF) is an
  8-bit-per-pixel bitmap image format.
• TIFF
• Tagged Image File Format (abbreviated TIFF) is a
  container format for storing images
• JPEG
• JPEG stands for Joint Photographic Experts Group,
  the name of the committee that created the
  standard
• is a commonly used method of compression for
  photographic images.

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Session Layer 5

• Session layer establish and manages the session
  between the two users at different ends in a
  network.
• Session layer also manages who can transfer the
  data in a certain amount of time and for how
  long.
• The examples of session layers and the
  interactive logins and file transfer sessions.
• Session layer reconnect the session if it
  disconnects.
• It also reports and logs and upper layer errors.

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Session Layer 5

• Examples of Session layer protocols are listed
  below
• RPC
• Remote procedure call, a protocol that allows a
  computer program running on one host to cause
  code to be executed on another host
• SQL
• Structured Query Language.
• SQL is a standard interactive and programming
  language for getting information from and
  updating a database.
• NetBIOS names
• The NetBIOS allows applications on separate
  computers to communicate over a local area
  network

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Transport Layer 4

• Transport layer manages end to end message
  delivery in a network and also provides the error
  checking and hence guarantees that no duplication
  or errors are occurring in the data transfers
  across the network.
• Transport layer also provides the acknowledgement
  of the successful data transmission and
  retransmits the data if no error free data was
  transferred.
• It also provides and error handling and
  connectionless oriented data deliver in the
  network.

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Transport Layer 4

• Examples are
• TCP
• The Transmission Control Protocol (TCP) is one of
  the core protocols of the Internet protocol
  suite.
• UDP
• User Datagram Protocol (UDP) is one of the core
  protocols of the Internet protocol suite.
• SPX
• IPX/SPX stands for Internetwork Packet
  Exchange/Sequenced Packet Exchange. It is a
  networking protocol used by the Novell NetWare
  operating systems. Like UDP, IPX is a datagram
  protocol used for connectionless communications.
  

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Network Layer 3

• The network layer determines that how data
  transmits between the network devices.
• It also translates the logical address into the
  physical address e.g computer name into MAC
  address.
• It is also responsible for defining the route,
  managing the network problems and addressing.
• Router works on the network layer and if a
  sending device does not break the data into the
  similar packets as the receiving device then
  network layer split the data into the smaller
  units and at the receiving end the network layer
  reassemble the data.

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Network Layer 3

• Examples of Layer 3 protocols include
• IP
• (Internet Protocol address), a computer network
  address
• IPX
• Internetwork Packet Exchange (IPX
• DECnet
• DECnet is a suite of network protocols created by
  Digital Equipment Corporation, originally
  released in 1975 in order to connect two PDP-11
  minicomputers.

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Data Link Layer 2

• Defines procedures for operating the
  communication links
• Frames packetsDetects and corrects packets
  transmit errors
• Protocols
• Logical Link Control
• error correction and flow control
• manages link control

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Data Link Layer 2

• Examples include
• IEEE 802.2
• IEEE 802.2 is the IEEE 802 standard defining
  Logical Link Control (LLC), which is the upper
  portion of the data link layer for local area
  networks.
• IEEE 802.3
• IEEE 802.3 is a collection of IEEE standards
  defining the physical layer, and the media access
  control (MAC) sublayer of the data link layer, of
  wired Ethernet. This is generally a LAN
  technology with some WAN applications.
• 802.5 - Token Ring
• Token ring local area network (LAN) technology

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Data Link Layer 2

• Examples include
• HDLC
• High-Level Data Link Control (HDLC) is a
  bit-oriented synchronous data link layer protocol
  developed by the International Organization for
  Standardization (ISO).
• Frame Relay
• frame relay consists of an efficient data
  transmission technique used to send digital
  information quickly and cheaply in a relay of
  frames to one or many destinations from one or
  many end-points.

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Data Link Layer 2

• Examples include
• FDDI
• Fiber distributed data interface (FDDI) provides
  a standard for data transmission in a local area
  network that can extend in range up to 200
  kilometers (124 miles).
• ATM
• Asynchronous Transfer Mode, a telecommunications
  protocol used in networking

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Data Link Layer 2

• The Data link layer performs the error check
  using the Frame Check Sequence (FCS) in the
  trailer and discards the frame if an error is
  detected.
• It then looks at the addresses to see if it needs
  to process the rest of the frame itself or
  whether to pass it on to another host.
• The data between the header and the trailer is
  passed to layer 3.
• The MAC(Media Access Control) layer concerns
  itself with the access control method and
  determines how use of the physical transmission
  is controlled and provides the token ring
  protocols that define how a token ring operates.
• The LLC shields the higher level layers from
  concerns with the specific LAN implementation.

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Physical Layer 1

• Physical layer defines and cables, network cards
  and physical aspects.
• It defines raw bit stream on the physical media.
  It also provides the interface between network
  and network communication devices.
• It is also responsible for how many volts for 0
  and how many for 1.
• Physical layer also checks the number of bits
  transmitted per second and two ways or one way
  transmission.
• Physical layer also dealing with the optical,
  mechanical and electrical features.
• Network Devices Hubs, Repeaters,

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Physical Layer 1

• Examples of specifications include
• FDDI
• 802.3
• 802.5
• Ethernet
• Ethernet is a family of frame-based computer
  networking technologies for local area networks
  (LANs).
• RJ45
• A registered jack (RJ) is a standardized physical
  interface for connecting telecommunications
  equipment (commonly, a telephone jack) or
  computer networking equipment. The standard
  designs for these connectors and their wiring are
  named RJ11, RJ14, RJ45, etc.

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Tutorial

• What is Network?
• What are the advantages of Network?
• What are the disadvantages of Network?
• What is ISO?
• What is OSI?
• Describe the OSI model.