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Unit 3 - Networks Part 2 - Network Topologies - Coggle Diagram
Unit 3 - Networks Part 2 - Network Topologies
Bus
The computers (nodes) are connected to a single cable on which data can be sent, called the bus.
The bus has terminators on each end, which are needed to close each end of the cable.
The bus carries data packets along the cable.
As the packets arrive at each computer system, it checks the destination address contained in the packet to see if it matches its own.
If the address does not match, the computer system ignores the packet. If the address of the computer system matches that contained in the packet, it processes the data.
Advantages
Easy to add more computer systems to the network without disrupting the network
Quick and easy to set up – well suited for temporary networks
Cost-effective as less cabling is needed
Disadvantages
It is difficult to troubleshoot the bus if there’s a fault
Limited cable length and number of stations – performance degrades as additional computers are added
If there is a problem with the main cable or connection, the entire network goes down
Low security – all computers on the bus can see all data transmissions
Proper termination is required
Data collisions are more likely, which causes the network to slow down. A collision is when two computers try to send a packet at the same time
Ring
Each node connects to exactly two other nodes, providing a single pathway for signals through each node.
Advantages
The transmission of data is simple as packets travel in one direction only, so no collisions.
Data is quickly transferred without a bottleneck – consistent data transfer speeds
Adding additional nodes has very little impact on bandwidth
Disadvantages
If any of the computer systems fail, the ring is broken and data cannot be transmitted efficiently
a problem with the main cable or connection and the entire network goes down
It is difficult to troubleshoot the ring
Because nodes are wired together, to add another you must shut down the network
Mesh
Each node relays data for the mesh network. All mesh nodes cooperate in the distribution of data in the network.
This is very reliable as it can 'self-heal' by reconfiguring around broken paths. This network is complex, expensive and difficult to set up. A large part of the network may be redundant
Star
Where one or more central switch, hub or computer acts as a central conduit to transmit messages
Disadvantages
Expensive to install as more cable is required
Extra hardware required, such as a hub
Advantages
Good performance/fast network speed
Easy to set up
Easy to add more computer systems without taking the network down
Failure of workstations will have no effect on the network
Minimal network collisions
Better security
Sending Data Over a Star Network
Computer A adds computer D’s address to packet
Computer A sends packet to switch
Switch looks at address on packet
Switch compares to stored list of addresses on network
Switch forwards packet to computer D’s address
