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What is a Computer Network?
What is a Computer Network?
So imagine a really large underground train network like the one here. Each station is a computer or a device. They are all connected together by tracks. People can travel in a train along the tracks to get to its destination. You can choose to take different trains to different destinations. A computer network allows computers to communicate with each other by sending and receiving messages. Data can travel on many different paths. So if a track is blocked, it takes an alternative route to ensure that it gets to its destination.
Network - A computer network or data network is a telecommunications network which allows computers to send and receive data. It also includes other devices to communicate with each other including phones, tvs, servers, printers etc.
Conceptual Question - What similarities and differences are there between computer networks and public transport train systems?
Concept Comparison - Computer Networks and Train Systems - click the arrow over there to read -->
Concept Comparison - Computer Networks and Train Systems - click the arrow over there to read -->
A train map and a computer network serve different purposes and operate in different domains, but there are some conceptual similarities that can be drawn for the sake of comparison. Let's break down the comparison into several aspects:
Topology:
Train Map: Represents the physical layout of train tracks, stations, and connections between them. It may include different lines, intersections, and transfer points.
Computer Network: Describes the arrangement of network devices such as computers, routers, switches, and connections between them. Common topologies include star, bus, ring, mesh, etc.
Components:
Train Map: Includes trains, stations, tracks, signals, and possibly depots or maintenance facilities.
Computer Network: Involves computers, servers, routers, switches, cables, and other networking devices.
Connections:
Train Map: Depicts the physical rails and connections between stations. Trains move along these connections.
Computer Network: Represents the logical or physical connections between devices. Data flows through these connections in the form of packets.
Traffic Flow:
Train Map: Reflects the movement of trains along the tracks and through stations.
Computer Network: Illustrates the flow of data packets between devices in the network.
Routing and Switching:
Train Map: Trains follow predetermined routes. Switches (railway switches) enable trains to change tracks.
Computer Network: Data follows specified routes through routers and switches. Routers make decisions about the best path for data to travel.
Stations and Endpoints:
Train Map: Stations serve as points where passengers board or alight, and trains originate or terminate.
Computer Network: Devices like computers and servers act as endpoints where data is either generated or consumed.
Redundancy:
Train Map: Some train lines might offer redundancy or alternative routes in case of disruptions.
Computer Network: Redundant paths and failover mechanisms are often implemented to ensure network reliability.
Signalization:
Train Map: Signals control the movement of trains, indicating whether a track is occupied or clear.
Computer Network: Networking protocols and signals ensure the proper communication and coordination of data transfer.
Security:
Train Map: Security measures may include surveillance, access control, and safety protocols.
Computer Network: Involves measures such as firewalls, encryption, and access controls to protect data and ensure network security.
While these comparisons provide some conceptual parallels, it's important to note that trains and computer networks operate in very different physical and operational contexts. The comparison is more of an analogy to help conceptualise certain aspects of computer networks rather than a direct equivalence in terms of functionality or operation.
Types of Computer Networks - How is Data Physically Transmitted?
Types of Computer Networks - How is Data Physically Transmitted?
Data can travel to its destination through a number of different mediums. Each medium carries data in a slightly different manner, but all types of networks allow data to make its way to its destination.
1. Wire
Copper Cable - sends pulses of electricity through the wire from the exchange to the computer.
This is the most common form of connection to your home. It also connects your home phone to the local exchange.
Its inexpensive and flexible (easy) to install
It doesn't allow for the fastest bandwidth (speed)
2. Fibre Optic Cable
Fiber Optic Cable - uses light to send bits (data) through cable at the speed of light - very fast internet.
Light flashes through the smooth inner glass like cable, bouncing off the sides at the speed of light. Our oceans have very long lengths of this cable to carry data a long distance and extremely quickly.
Its very expensive and can only be laid in straight lines, so not great for inside your home with lots of corners.
3. Wireless
Wireless technologies use radio signals to send bits to one place to another. Converts bits into a wave signal.
WIFI - Home/ school networks.
Radio Signals - Mobile Phones.
Wireless networks allow devices to be mobile and connected without being joined by cables.
Signals travel through walls making it really easy to install quite cheaply.
Wireless networks only have a limited range and sometimes you can have black spots where you get no connection.
Data Transmission Video
Data Transmission Video
ACTIVITY: Pros and Cons of Network Mediums
ACTIVITY: Pros and Cons of Network Mediums
Each of the above types of network mediums are used for different situations and needs.
You may download and save this table into your One Drive to help complete this question.
What is the Internet Video
What is the Internet Video
How is Data Sent over the Internet?
How is Data Sent over the Internet?
When you send information across the internet, data is broken down into small packages called Packets. Each Packet is like a parcel being sent in the mail and includes the following information.
The Data
IP address of the Sender
IP address of the Receiver - (like your street address)
Sequence number - so the packets can be put back together at each end
All computers follow a set of rules called protocols. That way all computers can communicate effectively and work under the same structures and parameters. This protocol is called TCP/IP.
How the Internet Works Videos
How the Internet Works Videos
Network Equipment to Connect to the Internet
Network Equipment to Connect to the Internet
Lets look at how you might connect to the internet at home.
Lets look at how you might connect to the internet at home.
To begin with you need to have an ISP or Internet Service Provider. They set up and maintain the infrastructure of connections outside your home so that you can access the web.
Inside your home you will be given a device called a Modem. A Modem sends and receives packets of data to and from your ISP converting them from analogue to digital signals.
Router - A router is a networking device that forwards data packets between computer networks. They are smart gateways that perform the "traffic directing" functions on the Internet. A data packet is typically forwarded from one router to another through the networks that constitute the internet work until it reaches its destination node. Most routers these days have an inbuilt modem.
Connections -The Router/Modem generally include 4 ethernet ports for hard wired connections and a wireless feature (WiFi) . This enables you to connect all your wired and wireless devices including:
Laptops and computers
Mobile phones
Tvs
Gaming Consoles
Google Home
Printers
EXTENSION ACTIVITIES: Pros and Cons of Network Mediums
EXTENSION ACTIVITIES: Pros and Cons of Network Mediums
Computer network design readings (essential for the below two games).
Computer network Noughts and Crosses game.
Further Information About Networks and the Internet
Further Information About Networks and the Internet
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