Chapter 1 · Computer Networks

1.5Network Topologies

Bus, star, ring, mesh and tree: five ways to arrange a network, with the advantages and disadvantages of each.

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Full Stack Developer · AI Engineer · Reviewed 21 Oct 2026 · 4 min read

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You can join the same computers in many shapes. One long cable, a circle, or a centre point with spokes. Each shape is called a topology. The shape changes how fast the network is, how much it costs, and what happens when something breaks.

There are two ways to look at a topology. The physical view shows the real cables and connections. The logical view shows the path the data takes.

Bus Topology

Every device hangs from one long cable, like lamps on a single wire. Data travels along that cable to the devices. It is simple and cheap, so it suits small networks. But if the main cable breaks, the whole network stops. That makes it a poor choice for large networks. In the book's Figure 1.8, each end of the cable has a "Terminator".

Star Topology

Every device has its own link to one central hub or switch. All data passes through that centre. It is easy to manage and to grow. If one computer fails, the others keep working. But if the central hub fails, the network stops. Star topology is widely used in modern networks.

Ring Topology

The devices form a closed circle. Data goes round the circle in one direction. Each device takes the data and passes it on to the next. So one failed device can affect the whole ring. Ring is more complex than bus, and it is rarely used today.

Mesh Topology

Each device links to many other devices. So there is more than one path between two devices. If one link fails, the data simply takes another path. This makes mesh very reliable and fault tolerant. The price is cost and complexity: it needs many cables. It is used in large and critical networks.

Tree Topology

A tree mixes bus and star. Several small star networks hang from one main cable, the backbone. Data flows from the root (the main node) out to the branches and smaller branches. It is easy to grow and suits large organizations. But if the backbone fails, the whole network can be affected. The book's Figure 1.12 shows hubs S1 and S2 and a "Concentrator(Hub)", each with its own nodes, joined to a "Backbone Cable" with a server.

Advantages and Disadvantages of Network Topologies

No topology is best for every job. Some are cheap and simple, some are reliable but costly, some are easy to grow. You pick the one that fits your needs. The book collects the points in Table 1.1:

Topology	Advantages	Disadvantages
Bus Topology	Simple and easy to install; Requires less cable; Cost-effective	Failure of main cable affects whole network; Difficult to troubleshoot; Performance decreases with more devices
Star Topology	Easy to install and manage; Failure of one device does not affect others; Easy to detect faults	Central device failure stops entire network; Requires more cable; Higher cost
Ring Topology	Data flows in an organized manner; No data collision; Equal access for all devices	Failure of one device affects whole network; Difficult to add/remove devices; Rarely used today
Mesh Topology	Highly reliable and fault-tolerant; Multiple paths for data; High security	Very expensive; Complex installation; Requires large number of cables
Tree Topology	Easy to expand; Suitable for large networks; Hierarchical management	Backbone failure affects whole network; Complex setup; More cabling required

Practice this topic

All MCQs of this chapter with answers

Short questions

1.Write the name of any two network topologies.2 marks
Answer
The book names five network topologies: Bus Topology, Star Topology, Ring Topology, Mesh Topology and Tree Topology. Any two, for example Bus Topology and Star Topology.
2.Define network topology. What is the difference between physical and logical topology?3 marks
Answer
From the book: "Network topology refers to the layout of a computer network. It explains how devices and cables are arranged." "Physical topology shows actual connections. Logical topology shows how data flows in the network." The book's Summary (p.17): "Network topology is the arrangement of devices and connections in a network, such as star, bus, ring, mesh, or tree."
3.What is bus topology?2 marks
Answer
From the book: "In bus topology, all devices are connected to a single main cable. Data travels along this cable to reach devices. It is simple and low in cost. Failure of the main cable can stop the entire network."
4.What happens in star topology if one device fails, and if the central hub fails?2 marks
Answer
From the book: "Failure of one device does not affect others. Failure of the central hub stops the network."
5.How does data move in ring topology?2 marks
Answer
From the book: "In ring topology, devices are connected in a circular path (as shown in Figure 1.10). Data moves in one direction around the ring. Each device receives data and passes it along. Failure of one device can affect the whole network."
6.Why is mesh topology very reliable?3 marks
Answer
From the book: "Multiple paths exist for data transmission. This increases reliability and fault tolerance. Failure of one link does not stop communication." "If one connection fails, data can use another path."
7.What is tree topology?3 marks
Answer
From the book: "In tree topology, devices are arranged in a hierarchical structure like a tree (as shown in Figure 1.12). It combines features of both bus and star topologies, where multiple star networks are connected to a central backbone. Data flows from the root (main node) to branches and sub-branches."
8.Write two advantages and two disadvantages of star topology.4 marks
Answer
From Table 1.1. Advantages: "Easy to install and manage", "Failure of one device does not affect others", "Easy to detect faults" (any two). Disadvantages: "Central device failure stops entire network", "Requires more cable", "Higher cost" (any two).

Long questions

1.Define network topology. Explain bus, star, ring, and mesh topologies with advantages and disadvantages.8 marks
Answer
1. Definition (verbatim): "Network topology refers to the layout of a computer network. It explains how devices and cables are arranged. Topology can be physical or logical. Physical topology shows actual connections. Logical topology shows how data flows in the network. Topology affects network performance and maintenance." Summary (p.17): "Network topology is the arrangement of devices and connections in a network, such as star, bus, ring, mesh, or tree."
2. Bus Topology: "In bus topology, all devices are connected to a single main cable. Data travels along this cable to reach devices." Table 1.1 advantages: "Simple and easy to install", "Requires less cable", "Cost-effective". Disadvantages: "Failure of main cable affects whole network", "Difficult to troubleshoot", "Performance decreases with more devices". (Figure 1.8: Bus Topology, with a Terminator at each end of the main cable.)
3. Star Topology: "In star topology, all devices connect to a central hub or switch (as shown in Figure 1.9). Data passes through the central device." Advantages: "Easy to install and manage", "Failure of one device does not affect others", "Easy to detect faults". Disadvantages: "Central device failure stops entire network", "Requires more cable", "Higher cost". (Figure 1.9: Star Topology.)
4. Ring Topology: "In ring topology, devices are connected in a circular path (as shown in Figure 1.10). Data moves in one direction around the ring. Each device receives data and passes it along." Advantages: "Data flows in an organized manner", "No data collision", "Equal access for all devices". Disadvantages: "Failure of one device affects whole network", "Difficult to add/remove devices", "Rarely used today". (Figure 1.10: Ring Topology.)
5. Mesh Topology: "In mesh topology, devices are connected to many other devices. Multiple paths exist for data transmission." Advantages: "Highly reliable and fault-tolerant", "Multiple paths for data", "High security". Disadvantages: "Very expensive", "Complex installation", "Requires large number of cables". (Figure 1.11: Mesh Topology.) A neat labelled sketch of each topology (Figures 1.8 to 1.11) can support the answer.
Aim for 350-450 words.
2.Explain tree topology with the help of Figure 1.12. Write its advantages and disadvantages.6 marks
Answer
1. Definition (verbatim): "In tree topology, devices are arranged in a hierarchical structure like a tree (as shown in Figure 1.12). It combines features of both bus and star topologies, where multiple star networks are connected to a central backbone."
2. Data flow: "Data flows from the root (main node) to branches and sub-branches."
3. Figure 1.12 labels: Backbone Cable, Server, hubs S1 and S2, Concentrator(Hub), Nodes A to I. Each hub with its nodes is one star network joined to the backbone.
4. Text: "It is easy to expand and manage large networks. However, failure of the backbone can affect the entire network. Tree topology is commonly used in large organizations."
5. Table 1.1 advantages: "Easy to expand", "Suitable for large networks", "Hierarchical management". Disadvantages: "Backbone failure affects whole network", "Complex setup", "More cabling required".
Aim for 150-250 words.
3."Choosing the right topology depends on network needs." Explain this statement using the advantages and disadvantages of network topologies given in the book.6 marks
Answer
1. The book's paragraph (verbatim): "Different topologies offer different benefits. Some are easy to install and low-cost (as shown in Table 1.1). Others provide high reliability and performance. Certain topologies are easy to expand. Some are difficult to manage and expensive. Choosing the right topology depends on network needs."
2. TIDBIT: "Some topologies are simple and cheap. Others are reliable but costly. Some are easy to expand. Others are difficult to manage. Choice depends on needs."
3. Match each need to Table 1.1:
  
  Simple and cheap: Bus ("Simple and easy to install", "Cost-effective"; text: "It is suitable for small networks").
  
  Reliable but costly: Mesh ("Highly reliable and fault-tolerant" but "Very expensive"; text: "It is used in large and critical networks").
  
  Easy to expand: Tree ("Easy to expand", "Suitable for large networks") and Star (text: "It is easy to manage and expand").
  
  Hard to set up or change: Mesh ("Complex installation", text: "Mesh topology is expensive and complex") and Ring ("Difficult to add/remove devices", text: "It is more complex than bus topology").
4. Close with the text's usage lines: "Star topology is widely used in modern networks", "Ring topology is rarely used today", "Tree topology is commonly used in large organizations".
Aim for 200-300 words.

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