A small mini-tutorial/intro on network topologies by cwk9.

-Iím doing this from memory so feel free to correct me if you see any mistakes.
-Excuse my crappy m$ paint diagrams.
-Keep in mind that network topologies arenít necessarily related to computer networks.
-Network topology is one of those vague general subjects that can very greatly depending to were/who you learned it from.

What the hell are network topologies?
Network topologies are basically how a network is laid out. There are two different sections of topologies physical topologies and logical topologies. The physical topologies are how the computers are wired. Were as the logical topologies are how the data flows around the net work. A network might have one type of physical topology and a completely different type of logical topology. Example1: 10BaseT uses an extended-star physical topology, but has a logical bus topology. Example2: FDDI uses a physical ring and a logical ring.

Why should I give a f**k?
1. Different topologies have different advantages and disadvantages.
2. Can help determine where collision domains occur
3. When some one says ďwere going to wire the network in a extend starĒ you will know what the heck there talking about.


1. Linear Bus Network topology (also known as a trouble shooting nightmare)
Every computer is connected wire.
Advantage: All the host computers can communicate directly.
Disadvantage: Break in the cable will disconnect host from each other.
Disadvantage: Biggie security risk. All computers can see all the signals to from all other devices.

2. Star Network Topology
Everything connects of a central point. The central point usually being a hub, server, switch Ö..ect
Disadvantage: When the central point goes so does your network. But at least youíll know were the problem is.
Advantage: Great for security because everything goes through the central point.
Disadvantage: Depending on the network and the devices used collisions could be a problem.
Advantage: Easy to setup. Just jack everything in to the central point.
Advantage: Keep wiring to a minimal.

3. Extended Star Topology
Each of the branches of the central star act as there own star. Advantages and disadvantages are the same as above.

4. Tree Network Topology
Think of a family tree. The tree topology is like a bus topology with branches with multiple nodes on them. The flow of information is hierarchical.

5. Irregular Network Topology
This is just a nice way of saying your network sucks and you have no idea what the hell youíre doing. Can be any network that has no obvious pattern and crappy wiring. These are often planned on a napkin.
Disadvantage: You network will suck if it even works in the first place.

6. Cellular Network Topology (wireless)
The network is built without using wires. You have two choices here electromagnetic waves: radio, microwave, X-rays, Gamma-rays (only produced by nuclear explosions and the sun but hey itís your network) Öect or some form of arcane magic. Basically your network will consist of what ever is in range at any given time. Most of the time cellular topologies are connected to other topologies.
Advantage: free roaming
Advantage: no wires
Advantage: cellular network topology just sounds cool
Disadvantage: range
Disadvantage: Your just throwing crap out there so any idiot with a laptop and a Pringles can could pick up stuff from your network.

7. Mesh (complete network topology)
Everything on the network is connected to everything else and there are multiple paths to every host. This is how the internet works.
Advantage: network will work as long as there is two or more host and a path between them.
Disadvantage: The amount if wire needed quickly becomes mind boggling.
Disadvantage: Carving information on stone is more cost effective.

8. Ring Network Topology
Just like it sounds, host are connected in a ring. Kind of like a daisy-chain thatís looped. Information travels in a circle and the host picks off the information it needs. Used in token ring and FDDI networks.
Advantage: Use of a token can allow for equally shared bandwidth.
Disadvantage: If the ring breaks you get to have the joy if finding out were it broke

9. Dual Ring Network Topology
Just like a ring network only it uses two rings for more fault tolerance.
Advantage: More fault tolerance
Disadvantage: Now you have two rings to worry about.