Skills Knowledge Enhancement - Networks

Networking Components

Notes containing descriptions of networking components and how they work together to create a computer network need to be put back together because a 'packet' of key words was lost in transmission. Here are the answers! and here are some more detailed notes on Networking.

Packet Switching

When a file travels through the internet it isn't sent as one document, it is broken up into lots of small 'data packets'. A 2MB file could, for example, be broken up into chunks of 512 bytes in size. Before each chunk is sent, it is given a 'header' containing the network IP address that it needs to arrive at and also details of the IP address from which it was sent. The header also gives each chunk of data a number and records how many chunks the data was split up into. These chunks of data with these additional pieces of information are referred to as packets.

Teach-it.com has a very good description of the process and a Word extract of this can be downloaded here. See also the Net-Seal 'Routing' animation.

This packet switching demo shows the transportation of data over the internet and there are some other brilliant animations that demonstrate network processes (see Net-seal Animations in the SKE dropbox).

A class network demonstration can be a good starting point for a discussion on packet switching (handshaking, missing packets, collisions, security, etc). Try and get some better jokes!

A funny and informative 10 minute animated web video on the transmission of information over the Internet is at http://www.warriorsofthe.net/movie.html

A series of flash animations explaining various networking operations have been produced by 'Teaching Computer Networks Through Simulation Experiments and Animation Library (NET-SEAL)'. They can be accessed through http://taibah.net/main/projects/net-seal/animations. Here are just two of them:-

AQA GCSE Computer Science: Networking - Topic 17 and other sections of the AQA Computer Science Specifications can be found on Youtube and some introductory notes on networking by Peter Dordal with minor updates by Andy Harrington can be viewed here. Links to ALL AQA topics can be found in the Awarding Body Materials section of this site.

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    Common Networking Terms

    A full description of the TCP, IP, DNS, DHCP, Default Gateways, Sub net Masks and much more is explained extremely well by 'Eli The Computer Guy'.

    TCP/IP

    The IP protocol deals with connecting two devices together whilst the TCP protocol is responsible for the transmission of the data, once the connection has been made. See Eli's video 0 - 16:54 mins for TCP

    DNS - Domain Name Server

    This translates a domain name into an IP address and returns that IP address to your computer. The root nameservers are located all over the world, mostly in datacenters near "hot spots" of Internet infrastructure or usage.  A very incomplete map is located here:  http://www.root-servers.org
    (The section on DNS is 21.00 - 25:00 mins in the video.)

    DHCP - Dynamic Host Configuration Protocol

    This is a network protocol that enables a server to automatically assign an IP address to a computer from a defined range of numbers (i.e., a scope) configured for a given network. In your home network this is normally situated on the Router. (See Eli's video - 25:00 - 35:15 mins)

  • System Development Life Cycle

    Software life cycle models describe phases of the software cycle and
    the order in which those phases are executed.  There are lots of
    models, and many companies adopt their own, but all have very similar
    patterns.

    There are various Software development models or methodologies. They are as follows:

    1. Waterfall model
    2. V model
    3. Incremental model
    4. RAD model
    5. Agile model
    6. Iterative model
    7. Spiral model
    8. Some of these models are summarised here and here are the "group's" notes: Agile, V-Model, Spiral, Waterfall and Incremental.
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