Telecommunication Models

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Telecommunication Models

• Day 1
• Mrs. Billet

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What is a telecommunication network?How does it
work?Give Examples.
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Telecommunication Network

• Number of computer or terminals that can be
  linked together.
• Allows data to be shared, software and
  peripherals, (printers, fax machine, and
  zip disk)

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Computer Networks

• Consist of nodes and links
• Node an end point,
• ex. Personal computer
• Link- channel between 2 nodes

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Why do I want a computer network?

• Better way to manage and share information
• Allows resources to be shared
• Centralized administration and control
• Security
• Collaboration

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Telecommunication Network

• Example McDonalds Restaurant Drive-Thru
• Give order in the driveway
• Order sent to kitchen
• Proceed to first window, pay
• Proceed to second window and pick up order.

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Telecommunication Network

• In each step, your order might have been sent to
  at least four different people. (Networked)
• The drink person, hot food person, cashier, and
  the final person who gives you your order.

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Protocol Rules

• Imagine a bank safe within a bank safe, or
  security check points.
• You have to go unlock the lock before you can
  proceed or go through security checkpoints as in
  a airport.
• You are stuck, until you go through the proper
  channel.

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Protocol Rules

• Many different kinds of protocols.
• For example Apple Computers, IBM Computer and for
  Microsoft products
• Protocols work at various levels in the OSI and
  several work together to build a PROTOCOL STACK.

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Protocols

• Make communication possible
• Set of Rules
• Facilitate communications between computers
• Computers must understand each in order to
  communicate

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OSI Open System Interconnect Model

Each layer handles a specific function in
transferring data through a network.
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OSI

• Communications Framework
• 1-the physical layer,
• 2-the data link layer,
• 3-the network layer,
• 4-the transport layer,
• 5-the session layer,
• 6-the presentation layer,
• 7-the application layer.

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OSI

• Control is passed from one layer to the next.
• A communication begins with the application layer
  on one end (for example, a user opening an
  application and typing a request).

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OSI

• The communication is passed through each of the
  seven layers down to the physical layer (which is
  the actual transmission of bits).
• On the receiving end, control passes back up the
  hierarchy.

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OSI Model Open Systems Interconnect Model

• 7 Layers
• Acronym A-P-S-T--N--D--P
• 7-6--5-4--3--2--1
• P-D-N-T--S--P--A
• 1-2--3--4--5--6--7

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OSI- protocols(like an onion- layer)
7 Layers
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7- Application Layer

• Application layer highest layer interfaces
  directly with software applications that require
  communication with other computers or devices.
• Access to network services.
• Examples file transfer, database access e-mail

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6- Presentation Layer

• The Presentation layer transforms data from the
  Application layer and formats it so that the
  Application layer of the receiving device can
  interpret the data.

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6- Presentation Layer

• Encryption, image and video formatting, character
  translation, and compression are all common
  functions at the Presentation layer.

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6- Presentation Layer

• Determines the format used to exchange data among
  networked computers.
• It sets the standards for systems to provide
  seamless communication from multiple protocol
  stacks.

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5- Session Layer

• Allows two applications on two different
  computers to establish, use, and end a connection
  called a session.
• It manages who can transmit data a certain time
  and the length of the transmission.

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5- Session Layer

• Establishes dialog control
• Regulates which computer transmits
• Regulates how long a computer will transmit

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Review

• What is a protocol?
• What is OSI?
• How many levels does OSI have?
• Name the two highest levels. And what are their
  functions?

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Telecommunication Models

• Day 2
• Mrs. Billet

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Review from yesterday

• What is a network?
• What are some examples?
• What is a protocol?
• What is OSI? And can you tell me some about some
  of the steps you learned about yesterday?

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COMMUNICATION NETWORKS

• Consists of a number of computers that can be
  linked together.
• Data can be shared, as well as software and
  peripherals, such as printers.
• Give examples of other peripherals?

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OSI Model Open Systems Interconnect Model

• Review
• Layer 7 Application
• Layer 6 Presentation
• Layer 5 Session

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4- Transport Layer

• Ensures that data are delivered error-free and in
  sequence with no loss, duplication, or
  corruption.
• Helps with recovery

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4- Transport Layer

• Packages long messages into small packets
• Sends receipt acknowledgements.

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3- Network Layer

• Addressing messages so that they are sent to the
  correct destination (address).
• It handles network problems.

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3- Network Layer

• Network problems can include
• Routing
• Traffic problems
• Routing
• Controlling congestion of data packets.

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2- Data-Link Layer

• Takes data messages form the network layers and
  provides actual transmission.
• Provides error-free delivery of data between two
  computers.
• Wiring, and signaling devices involved to
  transmit/receive data.

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2- Data-Link Layer

• Packages raw bits of data
• After sending data, it waits for an
  acknowledgement from the receiving computer.

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1- Physical Layer

• Transmits raw bit stream over the physical cable.
• Involves cables network interface cards (NIC)
  attachments, and hardware attachments.

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1- Physical Layer

• Transmits bits
• Regulates transmission
• Involves cables and hardware, and what
  transmission technique is used to send data over
  the cable.

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OSI Open System Interconnect Model
Each layer handles a specific function in
transferring data through a network.
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OSI Open System Interconnect Model

• 7 Layers
• Acronym A-P-S-T--N--D--P
• 7-6--5-4--3--2--1
• P-D-N-T--S--P--A
• 1-2--3--4--5--6--7

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Networking

• Networking connecting multiple nodes to
  facilitate information sharing, allows one
  computer to send information to and receive
  information from another computer.

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Network Topology

• Topology- refers to configuration of nodes
  and links in the network.
• Physical Layout

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Network Topology

• Topology can be described two ways.
• Physical Topology- physical layout
• Logical Topology- how signals pass
  between nodes.

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Network Topology

• Link- is the channel between two nodes
• Node- is an end point, such as personal
  computer

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Network Topology

• If four personal computers were linked
  together, the network would have four nodes.

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Primary Types of Topology

• BUS

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Primary Types of Topology

• STAR

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Primary Types of Topology

• RING

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BUS NETWORK

• Used for linking personal computers
• A single cable is often used.
• Nodes can be hooked on the cable as needed.
• Cable-efficient

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BUS NETWORK

• Simple and reliable system
• Data normally travels either direction in the
  bus

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BUS NETWORK
LINK
NODE
BUS
BUS
NODE
NODE
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Bus Topology- Daisy Chaining

• Bus cable runs from computer to computer,
  making each one a line in a chain.
• Commonly referred to as daisy chaining.

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BUS- Transfer of Information

• Also called a backbone network
• Only one computer can transfer information at a
  time.
• When the computer sends info, the info moves
  through the entire system

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BUS NETWORK- Terminator

• Terminator- device that absorbs the signals
  transmitted on a network cable.
• Terminator prevents signals from being bounced
  back along the cable and causing interference.

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BUS NETWORK- Terminator

• Terminator- is attached to each end of the LAN
  (Local Area network) to stop the signal
  from going back in the other direction.
• LAN- a network that does its work within a
  physically limited area and is usually owned by
  the user.

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Without a Terminator
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With a Terminator
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Interference

• Prevents messages from getting through
• Disrupts the networks efficiency

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BUS ADVANTAGES

• Inexpensive
• Simple Design
• Set up is simple, each computer must be connected
  to single length of cable.

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BUS ADVANTAGES

• Most bus networks use a single piece of copper
  cable to connect its computers together

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BUS DISADVANTAGES

• If a cable breaks somewhere in the middle, it
  splits the network into two.
• Repair can be difficult, because it is difficult
  to isolate the problem.

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BUS DISADVANTAGES

• If a computer is malfunctioning and causing a
  problem on the cable, the entire network is
  affected.
• Used for only a few computers, located in a small
  area (ex. Office)

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BUS DISADVANTAGES

• Only one computer can transfer information at a
  time.
• When the computer sends info, the info moves
  through the entire system

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Bus Physical Topology

• Uses either Thick Ethernet (10Base5) or Thinnet
  (10Base2)
• Thick Ethernet usually yellow, used as a backbone
  for the network.
• Thinnet- more flexible, more popular

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END OF LESSON REVIEW

• What type of topology is used with a LAN?
• Without a terminator what happens?
• What are the advantages and disadvantages of a
  bus topology?

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END OF LESSON REVIEW

• What is a node? What is a link?
• What color is thick Ethernet? And what is it used
  for?
• What is a daisy chain?
• What is networking?

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Telecommunication Models

• Day 3
• Mrs. Billet

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Review from yesterday

• What type of wires are used in a bus topology?
• What are some advantages of a bus topology?
• What are some disadvantage of bus?

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Review from yesterday

• What is interference?
• How does data move through a bus topology?
• What is an LAN?
• What is OSI?
• Why do want to have a network?

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Primary Types of Topology

• BUS
• STAR
• RING

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STAR NETWORK

• A star network has nodes that go out to each node
  from the computer.
• A star network is normally used when a central,
  or host computer is needed. Links go out to each
  node from the computer, like a star.

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STAR NETWORK

• Incorporates a hub, host computer or concentrator
  to provide a centralized location where all
  cables in the star meet.

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HUB-Star Topology

• It is small box with multiple cable connectors.
• Each computer on the network is connected by a
  cable to the hub.
• Hubs use twisted pair cable.

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STAR NETWORK
NODE
NODE
HOST COMPUTER
NODE
NODE
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STAR Transfer of Information

• Each computer is connected to a central network
  connector (hub).
• All information that transfers from one computer
  to another on the network passes through the hub.

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STAR- Setup

• Each computer must be relatively close to the
  network hub.
• Cable length between a computer and the hub
  should be less than 100 meters.
• Hubs commonly connect 4, 8, or 16 computers
  together.

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STAR- Setup

• In a large office building, it is common for each
  floor of the building to have its own hub.

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STAR- Expansion

• As long as there is a free port on the hub, only
  a cable is needed to connect another computer to
  a star network.
• Easy expansion, system does not have to be down
  to add additional computers.

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Advantages to Star Topology

• It is easy to add new computers or modify the
  network.
• Centralizing enhances network monitoring and
  management.
• A single computer failure does not affect the
  rest of the network. Easy to troubleshoot.

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Disadvantages to Star Topology

• Expensive, because of the amount of cabling need
  to join the nodes.
• More cable- more intricate installation.
• If the central hub fails, the network fails.

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RING NETWORK

• Ring Network consists of a number of nodes
  linked together in circular fashion.
• Data Travels in one direction in the ring
  format.

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RING TOPOLOGY

• Like a bus ride you have to stop at every stop
• One direction at one time.
• Takes a long time for information to get the
  right address.

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RING TOPOLOGY

• Not found in a LAN (Local Area Network).
• Ring has no ends
• Do not use terminators
• Very difficult to install because of circular
  configuration

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RING- Transfer of Information

• Information travels in one direction only.
• When a computer transfers information, it sends
  the information to the computer located next to
  it.

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RING- Transfer of Information

• If a computer receives information that is not
  addressed to it, the computer passes the
  information to the next computer along the ring.
  The computers continue to the information until
  it reaches the intended destination.

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RING- Setup

• Used to connect computers that are located close
  to each other.
• All the computers on a ring network must be
  attached to a single ring of cable.
• No beginning or end in a ring network

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RING- Expansion

• More difficult to expand than other types of
  networks
• Adding a new computer to a ring network, the
  cable must be broken to attach the computer.
• The network will not be functional until the new
  computer is connected.

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RING- Troubleshooting

• When a break in the ring occurs, all computers
  before the break will be able to exchange
  information, while those after the break will
  not.
• This makes it easy to determine the location of
  the faulty connection.

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RING- Cost

• Slightly more expensive to set up than other
  types of networks.
• Requires a greater amount of cable, since all the
  computers on a ring network must be attached to a
  single ring of cable, the network will

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RING- ADVANTAGES

• All computers have equal access to the rest of
  the network
• Even with many users, network performance is even,

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RING- DISADVANTAGES

• A single computer failure can impact the network.
• Isolating problems is sometimes difficult.
• Adding or removing computers disrupts network
  operations.

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RING NETWORK
NODE
NODE
NODE
NODE
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RING TOPOLOGY
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END OF LESSON REVIEW

• What are the three topologies?
• Describe the star topology?
• What is a hub?
• In a star how is information transported?

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END OF LESSON REVIEW

• Explain how you insert a computer in a star
  topology?
• What are the advantages and disadvantages of a
  Ring topology?
• Of the topologies which one is expensive and why?
  Which topology is the cheapest?

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Telecommunication Models

• Day 4
• Mrs. Billet

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Review from Yesterday

• What topology uses a hub?
• What are advantages and disadvantages of star
  topology?
• What are advantages and disadvantages of ring
  topology?
• When would you use a bus, star, and ring
  topology?

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TOKEN RING TOPOLOGY

• Most common LAN
• Developed by IBM
• All stations connect to a central wiring hub-
  Easier to troubleshoot failure.

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TOKEN RING TOPOLOGY

• Uses tokens which is a signal that regulates the
  flow of information on a network.
• Token Ring networks work by passing a single
  token form computer to computer.
• Before a computer can send data, it must collect
  the token. This ensures only one computer can
  transmit information at a time.

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TOKEN RING BANDWIDTH

• Operate at different speeds.
• Speed is determined by the type of cable used on
  the network.
• Token Rings use 4 megabits per second (Mbps)
  unshielded twisted pair cables
• Or 16 Mbps shielded twisted pair cables.

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TOKEN RING CABLES

• Many token rings are now using fiber-optic cable.
• Fiber optic cables allow transfer of data at very
  high speeds.

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TOKEN RING TROUBLESHOOTING

• Token travels in one direction around the
  network, so it is easy to determine the location
  of a problem or break in the network.
• Token will not pass if a break occurs

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TOKEN RING- Cost

• More expensive than other types of cable- based
  networks.
• Becoming less popular for new network
  installations.

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TOKEN RING TOPOLOGY
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LOGICAL TOPOLOGIES

• Describes the way a network transmits
  information.
• A workstation listens to see if another
  workstation is using the network.

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LOGICAL TOPOLOGIES

• Every workstation can send out data across the
  medium in variable-sized chunks called frames or
  packets.
• Distance is the biggest problem when broadcasting
  information.

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LOGICAL TOPOLOGIES

• Economical- Ethernet (10BaseT)- bus
• Star needs a hub
• Fiber optic Ethernet not affected by radiation

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NETWORK CONNECTIVITY

• Internetworking- connecting networks together to
  better use their capabilities
• Four basic interconnecting hardware
• Repeater
• Bridge
• Router
• Gateway

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REPEATER

• Operates only at the physical layer of the OSI
  model
• Repeats whatever it hears
• Strengthens the signal
• It takes the packet signal it receives, adds
  power back to it and sends it on its way.

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BRIDGE

• Used to connect different segments of a network
• Can connect networks using different topologies
• Work at layer 2 of the OSI Model
• Protocols establish the way data is transmitted

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ROUTERS

• Bridge the gap between two incompatible networks
  by performing protocol conversion.
• Routers are the backbone of the Internet
• Send data packets from a LAN to WAN

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GATEWAY

• Translates information between two different
  networks or two different data formats.
• Functions at layer 4 of the OSI Model
• Very expensive and difficult to install

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LAN- Local Area Network

• Resides in a small area, such as several
  buildings or classroom.
• Used to link personal computers, allowing
  individuals to share peripherals. Ex. Laser
  printer, or software
• File server is the computer that is used to
  store the software.

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WAN- Wide Area Network

• Covers a large geographic area
• Involves sending data over long distances
• Ex. Airlines use a WAN to keep track of flight
  bookings and schedules.
• Ex. Long Distance telephone companies

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END OF LESSON REVIEW

• Who developed the token ring topology?
• Why is it easier to troubleshoot a token ring?
• Explain what topology means.
• Describe the topology of a token ring.
• What is Internetworking?
• How is speed determined?

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END OF LESSON REVIEW

• What is a repeater, bridge, router, and gateway?
• What is the difference between a LAN and WAN?