Network Topology Types: Bus, Star, Ring, Mesh, Tree and Hybrid

A network topology is the arrangement of nodes, such as computers, switches, routers and phones, and the links that connect them in a computer network. It describes both the physical layout of cables and devices and the logical path that data follows between them. The main types are bus, star, ring, mesh, tree, hybrid and point-to-point.

This guide explains physical and logical topology, then walks through each type with a plain-text description of its layout, how data moves, its advantages and disadvantages, and real examples such as Ethernet and Wi-Fi. You will also find a comparison table, the full mesh link formula with worked examples, and a step-by-step method for choosing a design.

Key Takeaways

• Topology has two views: physical (the actual cables and device placement) and logical (the path data takes), and the two often differ.
• Star is the standard layout for wired Ethernet LANs, and Wi-Fi in infrastructure mode also centers each group of devices on an access point.
• A full mesh with n nodes needs n(n-1)/2 links, so 10 nodes need 45 links and 50 nodes need 1,225.
• Bus and ring designs use little cable but are fragile, while mesh designs are the most fault tolerant and the most expensive.
• Most real networks are hybrids, such as stars of switches joined by a partial-mesh core.

What Is Topology in a Computer Network?

IBM defines it as "the physical and logical arrangement of nodes and connections in a computer network" (IBM). Cisco puts it in similar terms, saying topology "is used to describe the physical and logical structure of a network," including how nodes are placed, how they are interconnected and how data flows (Cisco).

In networking courses, "topology" in a computer network (sometimes shortened to "topology in CN") comes from mathematics, where it describes how points are connected regardless of distance or shape. A node is any device that sends, receives or forwards data. A link is the connection between two nodes, such as a copper cable, fiber strand or radio channel. The layout you choose affects cost, speed, reliability, security and how easily the network can grow.

Physical vs Logical Topology

Cisco calls the physical layer the underlay and the logical layer the overlay. The physical topology "maps the actual connections in a network, such as wires and cables and the placement of various components." The logical topology shows how data moves between devices regardless of that wiring.

That last row is a real case. Training material from the University of New Hampshire InterOperability Lab describes an early Ethernet hub as a "bus in a box": the wiring is a star topology with a logical bus (UNH IOL). Older Token Ring LANs did the reverse in a sense, cabling stations to a central unit that passed data around an internal ring, a design often called a star-wired ring.

Network Topology Types at a Glance

The table describes each layout in words.

Bus Network Topology

In a bus network, a single cable called the backbone connects every device. A project report written for Washington University in St. Louis professor Raj Jain's course explains that the sender broadcasts to all nodes, "but only the desired recipient digests the message" (WUSTL survey).

• Advantages. easy to install, uses the least cable, and a failed device does not affect the others.
• Disadvantages. a break in the backbone stops all communication, performance drops as nodes are added, and every device sees all traffic, which weakens security.
• Real example. the first IEEE Ethernet standard (1985) ran on shared coaxial cable in 10BASE5 "ThickNet" and 10BASE2 "ThinNet" bus layouts. According to UNH IOL, a single break in the coax could cut off many nodes, and adding or removing nodes disrupted the network.

Star Network Topology

In a star, every device has its own cable to a central switch or hub. The central device forwards traffic to the right port. A switch sends each frame only to its destination port, while an old hub repeated it to every port.

• Advantages. one bad cable affects only one device, faults are easy to find, and adding a device just means plugging in another cable.
• Disadvantages. it needs more cable than a bus, the number of devices is limited by the switch's ports, and if the central device fails, the whole star goes down.
• Ethernet example. the 10BASE-T standard (IEEE 802.3i, 1990) moved Ethernet to twisted-pair cable in a star around a hub, and UNH IOL notes it became dominant in the early 1990s. Today's office and school LANs are stars built around switches.
• Wi-Fi example. NIST explains that IEEE 802.11 defines two basic topologies. In ad hoc mode, devices talk directly. In infrastructure mode, an access point "connects wireless STAs to each other or to a DS, typically a wired network," and NIST calls it "the most commonly used mode for WLANs" (NIST SP 800-48 Rev. 1). Each access point and its clients form a star.

Ring Network Topology

In a ring network topology, each node connects to two others, and the first and last nodes are joined to close the loop. Messages travel through intermediate nodes, which act as repeaters. Many ring networks control access with a token, a special frame that gives the holder permission to transmit.

• Advantages. orderly access with no collisions when token passing is used, and a dual (bidirectional) ring can reroute traffic the other way if one link fails.
• Disadvantages. in a single ring, one broken link or node can disrupt the whole loop, delay grows with every hop, and adding a node means recabling its two neighbors.
• Real example. Token Ring LANs used a star-wired ring, where stations were cabled to a central access unit that formed the loop inside.

Mesh Network Topology (Full and Partial)

Mesh topologies are built on path redundancy. In a full mesh, every node links directly to every other node. In a partial mesh, only some nodes have multiple direct links, and the rest reach each other through neighbors. The WUSTL survey notes that full meshes are "usually restricted to networks with a small number of nodes" and that "the internet employs Mesh Network Topology."

• Advantages. no single point of failure, traffic can take the fastest or least busy path, and faults are easy to isolate because links are dedicated.
• Disadvantages. high cost for cable, ports and setup, complex configuration, and each node needs routing logic to choose paths.
• WAN example. carriers and large companies connect core routers in a partial mesh so that a fiber cut between two cities reroutes traffic through others.
• Data center example. Cisco describes spine-and-leaf designs in which every leaf switch connects to every spine switch, a partial mesh that gives each server several equal paths.
• Wireless example. Cisco defines a wireless mesh as "a type of topology where the wireless access points connect to each other to relay information," with only the primary access point needing a wired connection (Cisco Business mesh FAQ).

Tree Topology

A tree, also called a hierarchical topology, links several star networks under a higher-level node or along a backbone.

• Advantages. easy to expand by adding another branch, and cable faults stay local to one branch.
• Disadvantages. if a branch switch or its uplink fails, that whole section goes offline, and the root is a critical dependency.
• Real example. Cisco's layered campus model, with access, distribution and core layers, is the hierarchical design used in many enterprise and university networks.

Hybrid Topology

A hybrid combines two or more basic topologies. Common forms are star-bus (several stars linked by a backbone) and star-ring. IBM notes that hybrids balance scalability and reliability but are harder to design and cost more to maintain.

• Advantages. each part of the network can use the layout that fits it best.
• Disadvantages. more equipment, more planning and more complex troubleshooting.
• Real example. a typical company network uses stars of switches at the access layer, a partial mesh between core switches and point-to-point links to branch offices.

Point-to-Point Network Topology

A point-to-point network topology is the simplest of all: two nodes and one dedicated link. IBM notes it has limited use as a whole network design, but it is a common building block.

• Advantages. full link capacity for two endpoints, simple setup and easy troubleshooting.
• Disadvantages. it does not scale on its own, and the link is a single point of failure.
• Real example. a leased line or fiber link between two offices, or a pair of access points in bridge mode, which NIST says can "create point-to-point connections to join two separate networks."

The Mesh Link Formula n(n-1)/2

To find the number of links in a full mesh, count how many connections each node needs and remove the double counting. Each of the n nodes connects to the other n - 1 nodes. That gives n(n - 1) link ends, but every cable has two ends, so divide by 2.

Links in a full mesh = n(n - 1) / 2

Worked example: a small office wants a full mesh of 6 routers.

1. Write down the number of nodes: n = 6.
2. Find the links per node: n - 1 = 6 - 1 = 5. Each router needs 5 ports for the mesh.
3. Multiply: n(n - 1) = 6 × 5 = 30 link ends.
4. Divide by 2 because each link joins two routers: 30 / 2 = 15 links.

Check the answer by counting: router A links to B, C, D, E and F (5), B adds links to C, D, E and F (4), and so on, giving 5 + 4 + 3 + 2 + 1 = 15. The table shows how fast the number grows compared with a star, which needs only one link per device.

This quadratic growth is why full meshes stay small and large networks use partial meshes. Some textbooks also give n(n - 1) for simplex (one-way) links, so read the question carefully to see which count it wants.

Topology Comparison Table

Ratings are relative, comparing topologies for a network of the same size.

How to Choose a Network Topology

Cisco advises matching the design to the network's size, scale, budget, performance and redundancy needs, and planning for growth. A simple process looks like this:

1. List the devices and locations. Count users, servers, printers and access points by room, floor and site.
2. Set the reliability target. A home network can tolerate a router reboot, while a hospital system cannot.
3. Find single points of failure. Ask what happens if one cable, switch or site fails, and add redundancy only where an outage would be costly.
4. Estimate cabling and hardware. Use the link counts above. A star of 30 devices needs 30 runs, while a full mesh of the same 30 would need 435 links.
5. Plan for growth. Star and tree layouts add devices easily, while bus and ring layouts do not.
6. Consider security and management. Centralized designs make access control simpler, while decentralized designs offer more path diversity.
7. Draw the physical and logical diagrams. Mapping both views helps you spot bottlenecks before you buy anything.

Most small and midsize networks end up with a star or tree of switches at the edge and a partial mesh at the core. Lab work on these designs is covered under IT assignment help, while engineering homework help handles related signal questions and programming homework help covers network scripting.

Getting Help with Network Topology Assignments

Topology questions mix diagrams, formulas and design trade-offs, and physical and logical layouts are easy to confuse. If you want a tutor to walk through a design problem or check your reasoning, the computer science assignment help page explains how to get step-by-step support.

Frequently Asked Questions

What Is Meant by Topology in Networking?

Topology in networking means the layout of a network, including which devices are connected and how data travels between them. It has a physical view, covering cables and device placement, and a logical view, covering the path data takes.

What Is a Logical Network Topology?

A logical network topology describes how data flows between devices, regardless of the physical wiring. For example, an old Ethernet hub was wired as a physical star but behaved as a logical bus because it repeated every signal to all ports. Logical layouts are set by configuration, such as VLANs and routing.

Which Network Topology Is Most Common?

The star is the most common for local networks. Wired Ethernet LANs connect each device to a switch, and Wi-Fi in infrastructure mode, which NIST calls the most commonly used WLAN mode, centers devices on an access point. Larger networks combine these stars into tree or hybrid designs.

What Are the Advantages and Disadvantages of Mesh Network Topology?

Mesh offers multiple paths, no single point of failure and easy fault isolation, which makes it ideal for backbones. The drawbacks are cost and complexity, since a full mesh needs n(n-1)/2 links and every node must run routing logic. Partial meshes keep most of the reliability at a lower cost.

What Is the Difference Between Star and Bus Topology?

A bus connects every device to one shared backbone cable, so a single break can stop the whole network. A star gives each device its own cable to a central switch, so a cable fault affects only one device, but the switch becomes a single point of failure. Ethernet moved from bus to star in the early 1990s.

How Do You Draw a Network Topology Diagram?

List every device and give each a symbol, such as a circle for a computer and a box for a switch. Draw each physical link as a line, label interfaces and IP subnets, and add a second diagram for the logical view if it differs.

Definitions and examples come from IBM, Cisco, NIST SP 800-48 Rev. 1, the University of New Hampshire InterOperability Lab and a Washington University in St. Louis course survey, as of Nov. 2026.