Network Topologies
    What is Network Topology :
    
        - Network topology refers to the physical or logical layout of a network.
- It defines how devices/nodes  are interconnected and secondly  how data flows between them.
- Topologies are useful in planning a new network.
There are two main types of topologies :
    
        - Physical topology : It is actually the layout of cables and hardware.
- Logical topology : It defines how data moves through the network, regardless of its  physical design.