Thursday, 19 April 2012

Network Devices

    The Weymouth college network is mainly in the format of a local area network but is divided into three separate locations. These networks can be found in Weymouth and Dorchester. They all have different methods of transferring data for example one method Weymouth college utilizes is by transferring microwaves. The tool it uses to enable the transferring of data is simply by using wireless mediums which are located all over Weymouth College in the form of Hubs or switches.

     The layout of the Weymouth College would classify it in the category of being in the star topology. Different places in the college use different mediums for example as the primary Hub is located in the Holworth building it then enables physical wires such as fibre optic cables or Ethernet cables to be connected to the desktops in that building this would ultimately result in a vastly higher connection speed in the holworth building than any other building around the college which have to be connected via wireless mecum. For example the fibre optic cable has the capacity to transfer up to 1GB speed per second, while the wireless medium is restricted to 54mbps.

     The fibre switch backbone which is the main server for Weymouth College divides its speed evenly throughout all the buildings. Each building of the college has a node in it which collects the data and then passes it onto the main node. The reason it odes this and doesn’t go straight to the main node is that it stops the network form receiving too much traffic which may crash it. `Peripheral devices such as printers are connected via Ethernet cable. In the learning gateway the computers are positioned in circles around many tables around the room. The desktops are all located to the closest printer. There are locations in the college which are remote and are unable to receive a wired connection to the main server therefore they use the following mediums Microwave, ADSL Broadband and Leased Lines.

    The Star topology is perfect for the college as its very error tolerant. For example if a building has an error this wouldn’t affect the other buildings. The only possible way the all systems could go down would be if the primary switch goes down. The star topology also has many other advantages such as if there is a fault it is quite easy to troubleshoot because the topology’s layout isolated and centralises all the devices. An error which occurs quite a lot on the Weymouth College network is when there’s a lot of traffic from one area using a large quantity of bandwidth this can cause significant slow down to other areas demanding the bandwidth. A simple occurrence of this would be everyone tried signing in on a machine at the same time this would cause significant slow down for everyone therefore possible causing it to take 5 times as long to log on that it normally would, another disadvantage of this topology is that settings up all the complex wiring can be very costly, significantly more than other topologies. The star topology is the best topology to use in a college or school environment as other topologies such as the ring topology has many disadvantages such as errors are very hard to identify and also if there’s a break in the main cable then it would cause the shut down of the whole system. Adding these both disadvantages together would result in the network being down quite often and being down for a long duration. Another advantage of why to use the star topology for a college environment is that it’s very east to expand so if the college wants to construct new buildings or facilities which they want to have network access, it would be done with little stress and with no danger or damaging the system.
Weymouth College uses a Cisco Firewall to enable the college to keep all of the internal resources from being accessed by external intruders. Most of the ports on the Weymouth College server are blocked excluding port 80 which enables users to access the Weymouth college webpage. Which a user can sign into which then enables users to have access to resources for their course.

Students who are connected to college network would be able to browse the internet although there is software which blocks certain sites which the college deems to be inappropriate for a learning environment. This is also to stop the college network to be hit with a virus.

There is also another function on the college network called “Packeteer” which enables the network admin to control the whole network traffic as this would enable faster speeds on the network and it stops people using the whole network to themselves for example if two students were downloading lots of files this would normally cause slow down for the whole network but on this network it wouldn’t cause slow down.  This is because that user would only be given about 1% of the total bandwidth.

   The Star topology uses the regular LAN Ethernet protocols which consists of the some Wide area network applications and manages the maximum packet size. The college network uses Microsoft Outlook but has been customised to the WAN so that you can send emails to other students or lectures the network identifies the students email by a student id which is given to all the students. The College email system works in a way which only enables traffic to flow into the server and back out again so if a user hacked the E-mail they wouldn’t be able to access the main internal servers. So the only people who can obtain information from the internal server would be people who are on a machine within the network. The computers on the internal server start lower on in the network topology while external computers start a lot higher for example. Computers on the internal network have do go through the web proxy and many of the hubs and switches.  As a result this takes the external users through a different path in this case a path which restricts the access to the network.

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