STATE AND EXPLAIN
💡 The Bus topology description of a network can also include or imply the nature of the data flow through the network. And practical term used in professional training.
A bus is the simplest physical topology. It consists of a single cable that runs to every workstation. This topology uses the least amount of cabling, but also covers the shortest amount of distance. Each computer shares the same data and address path. With a logical bus topology, messages pass through the trunk, and each workstation checks to see if the message is addressed to itself. If the address of the message matches the workstation’s address, the network adapter copies the message to the card’s on-board memory. It is difficult to add a workstation have to completely reroute the cable and possibly run two additional lengths of it. If any one of the cables breaks, the entire network is disrupted. Therefore, it is very expensive to maintain.
FAQ Execution
Commonly six main types: Bus, Star, Ring, Mesh, Tree, and Hybrid.
It describes how devices are physically connected.
It describes how data flows within the network.
It affects performance, scalability, cost, and fault tolerance.
All devices are connected to a single backbone cable.
It is the central communication line that connects all nodes in a bus network.
Advantage: Low cost and simple installation.
Disadvantage: If backbone fails, entire network fails.
Coaxial cable (like RG-58) is commonly used.
Bus topology is suitable when:
Network size is small, Budget is limited, Temporary network is required, Less number of devices (generally less than 20)
Early Ethernet standard 10BASE2 and 10BASE5.
Resistors placed at both ends of the cable to absorb signals and prevent reflection.
Without terminators, signal reflection causes network collision.
When signals bounce back from the cable end and interfere with new signals.
Data travels in both directions along the backbone cable.
Each device checks the destination MAC address in the packet.
CSMA/CD (Carrier Sense Multiple Access with Collision Detection).
When two devices transmit data at the same time.
Efficiency Formula:
Efficiency = Data Transmission Time / (Data Transmission Time + Propagation Delay)
I) Install backbone cable (Required: Coaxial cable & Cutter, Crimping tool, BNC connectors, Cable tester)
II) Attach T-connectors (A connector used to attach devices to the backbone cable)
III) Connect devices (Its called nodes)
IV) Add terminators at both ends
Bandwidth is shared among all devices.
Traditional bus networks do not use switches.
Mostly: Star topology & Spine-leaf architecture
Small IoT networks, Industrial communication and Temporary network setups
In Bus Topology, all devices connect to one backbone cable.
Formula for Number of Links : 'L=N−1'
Where:
L = Number of links (?)
N = Number of devices (20)
L=20−1=19
So 19 links are required to connect 20 devices.
Bandwidth Sharing Formula : 'Bd = B/N'
Where:
B = Total bandwidth of bus topology (100)
Bd = Bandwidth per device (?)
N = Number of devices (20)
Bd = 100/20 = 5 Mbps
So 5 Mbps bandwidth will share per devices.
Formula for calculating cable requirement :
'Total Cable = Distance between nodes × (Number of Nodes – 1)'
If Distance between nodes = 5 meters
Number of nodes = 10
Total Cable = 5 × (10 – 1)
Total Cable = 45 meters
