The previous post has been discussed about the star topology. Previously also discussed about what is a network topology, but on this occasion will be discussed briefly about what is a network topology. On a computer network, the word topology refers to the layout array of a network device element on a computer network.
Network topology is differentiated into two forms, namely physical topology and logic topology. The physical topology is about how the placement of a network device on a computer network, while the logic topology is about how the data flows on each computer device.
On this occasion will be discussed in full about the understanding of bus topology, characteristics, how communication occurs, as well as the advantages and disadvantages of the bus topology.
Definition of Bus topology
Bus topology is one type of topology that often used in small scale network. In topology bus all network devices are connected on a single cable called Bus. This Bus then becomes the center of data traffic where all network devices communicate with other network devices that are currently connected.
Then the second type of bus topology is Distributed Bus, which distinguishes this type of topology with the first type of topology is the branch formed on the main cable, and each branch has its own endpoint. In short this distributed bus is a composite of several linear buses.
Bus topology Characteristics
The bus topology has the characteristic of a single cable that stretches along the network, this cable that then become the backbone of the network. The type of cable commonly used in the bus topology is coaxial, all network devices are connected with this cable using T connector. This connector plays a role to divide the path to allow for devices to connect on the main cable (Backbone).
Another characteristic that is owned by the bus topology is the Terminator at each end of the network cable. This Terminator serves to absorb the singal and prevent it from being reflected back, because if it happens it will cause a signal collision.
How is communication happening on Bus topology?
In a network of bus topology, all network devices connected to the same main cable can send or receive data packet, but to perform data transmission, the main cable must be in Free State, in the sense that no other device is doing data exchange. This is done to avoid data collision on the main cable, the whole process is set up using a protocol called Carrier Sense Multiple Access/Collision Detection (CSMA/CD).
To transmit data from one computer to another computer, the sender's computer will membroadcast a signal and the signal will propagate along the network cable, then inspect each device on the network. If the device has the same MAC address or IP address as intended, the device receives it, but if the device has a MAC address or an IP address that is not the same then the computer will remove the signal The.
In order to avoid the occurrence of signal collision a terminator is placed at each end of the network cable, it aims to prevent signal on the main cable is not reflected back.
Advantages and disadvantages of Bus topology
Here are some of the advantages that the bus topology has:
1. Easily add new devices
To add a new device to the bus topology is quite easy, you just need to connect the cable using a connector with a long enough so that the device can connect to the main network.
2. Less cost required
If comparing the cost of the bus topology with Ring, star or hybrid topology, then the bus topology is the most inexpensive to implement. This is because the bus topology requires only one cable that acts as the main cable where communication between computers is engaged.
3. Does not require hubs or switches
In addition to the bus topology also does not need a hub or switch to be able to work, because the linear nature of the network allows data to flow freely to the entire network. But nevertheless the bus topology also requires a terminator that must be mounted to the end of the main cable to be able to function normally.
4. Terminator cable does not require power
The Terminator used in the bus topology is a passive device. The Terminator is made of resistors and capacitors, which means it doesn't need the power to be able to work. This is what makes the bus topology can be implemented anywhere you need.
In addition to the advantages described above, the bus topology also has some disadvantages when compared with other topologies, namely:
1. Adding devices slows down the network
Looking at the way the bus topology is communicating with other computers, it can be concluded that the more devices connected on the main cable, the longer the time it takes to do data exchange.
2. Security issues
Every computer on the bus topology connected with the main cable is able to see the entire transmission of data that is happening on all other computers. This is a problem for the security of the bus topology, because everyone can see what others are doing.
3. Damage to the main cable will affect the entire network
Because the main cable is the center of data traffic, if there is a small mistake, it will impact the entire network. This resulting impact could be damage to the entire network or break the network into two parts.
A few discussions about the bus topology. For those of you who need a small-scale network topology, the bus topology can be one solution with various advantages and disadvantages it has.
There is actually no limit given in terms of the number of devices connected in the bus topology, but with the number of devices connected then the risk of slow data speed and problems that may occur on the device is getting bigger.