Monday, January 19, 2009

Blog One: Introduction to the internet

After going through today's lecture, i decided to research further onto the subject of the different types of network topologies. As included in our lecture slides, there are 3 types of computer networks, however, do any of us know exactly how each of them work? I definately do not.In my blog entry this week, I explore into further detail about each of these standard structures and how they aid in the networking of the internet.Firstly, in computer networking, topology refers to the layout of connected devices. I will be touching on 5 standard topologies, i call it BRSMT


No 1: Bus Topology


As shown in the diagram, computers are connected via a common backbone by a single cable. This single cable functions as a shared communication medium that devices attach or tap into with an interface connector. Eventually, a device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message.




IMPT NOTE: Bus networks work best with a limited number of devices. Performance problems are likely to occur when more than a few dozen computers are added to the network bus. In addition, if the backbone cable fails, the entire network effectively becomes unusable.



No 2: Ring Topology
For every device in a ring network,there are exactly 2 neighbours for communication purposes. Every single message needs to travel through a circular motion in the same direction. Failure to do so breaks the loop and breaks up the entire network.



IMPT NOTE: Ring topology are often used in school campuses or office buildings.



No 3: Star Topology

The star topology is a typical home network. It consist of a central connection point called a "hub" that may be a hub, switch or router. Devices typically connect to the hub with Unshielded Twisted Pair (UTP) Ethernet.


IMPT NOTE: A failure in any star network cable will only take down one computer's network access and not the entire LAN. BUT If the hub fails, the entire network also fails.


No 4: Mesh Topology



The mesh topology is unlike each of the previous mentioned in that messages sent on a mesh network can take any of several possible paths from source to destination. A mesh network in which every device connects to every other is called a full mesh.




IMPT NOTE: Partial mesh networks also exist in which some devices connect only indirectly to others.


No 5: Tree Topology







This is my favorite topology because it integrates multiple star topologies together onto a bus. In its simplest form, only hub devices connect directly to the tree bus, and each hub functions as the "root" of a tree of devices.

IMPT NOTE: This tree topology supports future expandability of the network much better than a bus or star.
My conclusion on the subject of computer networking is that topologies still remain an important part of network design theory. Each and every one of them are important and uniquie in its own way, hence we should all take some time and effort to study the diagrams. I hope that through this mini lecture on the different topologies, fellow classmates will gain more knowledge regarding computer networking.







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