Topologies Case

A topology is the shape of a local-area-network or other

telecommunications. Our Government, schools, and business all have

some type of physical topology layout design for there network. Topology

is the way a network is physically set up to send protocols from node to

node; it is the arrangement of computers, cables and other types of nodes.

There are two different kinds of topologies, physical and logical. The most

commonly used topologies are Bus, Star, Ring, and Mesh.

Each topology has pros and cons when they are connected to a

network. The administrator needs to keep both factors of advantages and

disadvantages in mind when deciding which topology system will be used.

In addition, they should know how many connected modules and the

estimated amount of traffic that will be on the network. Also, make sure

that the structure will be within the budget, and making sure it can be

configured in the given time frame.

Sometimes in large networks, you can combine different topologies

making them compound topologies. Combining topologies gives the option

to making a network as big as needed. Again, the pros and cons of these

topologies would need to be examined to see which one is best suitable for

the grid.

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Topology has two parts, physical and logical. Physical topology is the

actual wiring of the network and the form the computers are able to send

data through a network. They start with a small network using a simple bus

network to a mesh network that can get very complicated. The most

frequent topologies used are bus, star, ring and mesh. Advantages and

disadvantages of each topology will be significant to which one would be

best.

Bus topology (also known as a drop) is a LAN architecture in which

all nodes are connected by one linear bus (cable) and transmissions from

network stations propagate the length of the cable medium and are

received by all other nodes.(Network Dictionary) The cabling used for this

type of topology is twisted pair, coaxial and fiber optic. A signal from the

resource is announced and it travels to all workstations connected to the

backbone. Even though the message is announced to every workstation,

only the intended Mac address or IP address will accept the message. The

advantages to the layout it is very simple and easy to use. It requires a

small amount of wire to connecting computers so therefore, it is less

expensive.

Disadvantages of the Bus topology are that there is no security. If a

client is sending data to another client on their network the receivers can

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capture the broadcasts very easily.(Communication and Computer

Network) Plus, only one workstation can send data at a time.(IP Mulitcast)

If one computer breaks, it will not affect the other computers in the network,

but if the backbone fails, the entire network stops working. Terminators are

needed at both ends of the backbone cable and for this it is not meant to be

used in a large building for a stand-alone solution.

Star topology is one of the most common computer network

topologies. The network nodes are connected to a central node, which

rebroadcasts all transmissions received from any peripheral node to all

peripheral nodes on the network. All peripheral nodes may thus

communicate with all others by transmitting to, and receiving from, the

central node.(Network Dictionary) All nodes are connected to a central

point, for example a hub or switch that connects using cabling such as

twisted pair and fiber optic. This decreases the chances of a dropped

network.

The advantages of this type of topology are that it's easily secured

and manageable. Also, if you often switch nodes, the star is easier to

add/delete workstations by just unplugging it form the hub or plugging one

in. Given that each client is hardwired to the hub, data is sent twice as fast

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as the bus topology.(Network Certification) This design allows you to

breakdown your network into small clusters of workstations that are

physically in the same vicinity.

The main disadvantage of Star Topology is if the central point,

hub/switch,