Network Topology Explained With Diagram & Examples
Network Topology
When networks are designed the topology must be considered. This can lead to either an inefficient network or a high performance and efficient network. By definition, a network topology is defined by the nodes and links in a network and how are arranged. A network node is a network device that can send, receive, store, or forward data at various points in the OSI & TCP/IP reference model. A network link connects these nodes and may be either cabled or wireless links.
Physical and Logical Network Topology
Within the network topology, it can either be referring to the logical or physical topology. A physical topology refers to physical connection between nodes or network devices. A logical topology refers to logical connection between nodes and how data transfers between them. The examples below can be used to understand both types of network topologies.
As mentioned, understanding different network topology types provides the foundation for building a successful network. There are a myriad of network topologies but the most commonly are the bus, ring, star, and mesh network topologies.
Centralization and Decentralization of Network Topology
In terms of understanding network topology, you must consider whether you require a centralized or decentralized topology. Centralization can be found in the star topology whereas decentralized network topology can be found in partial mesh topology. Each has its own advantage in node-to-node communication.
Physical Cabling in a Network Topology
Network topology is connected through physical cabling, below we see an overview of the fastest transmission speed to the slowest:
- Optical Fiber Cable
- Optical fiber is the fastest cabling as it is made from glass and has advantages over traditional metal wiring. It can send data at trillions of bits per second and used for long runs (interconnect between continents through the ocean).
- Twisted Pair Cable
- If not fiber cabling, the second most common and fastest is the twisted pair cabling. It is copper wires where transmission speed ranges from 2 million bits per second to 10 billion bits per second. It can either be Untwisted Pair (UTP) or Shielded Twisted-Pair (STP), each with its own purpose.
- Coaxial Cable
- Coaxial cable is often used by cable companies (internet service providers) to send data into LANs (homes). It is primarily copper and transmission speed ranges from 200 million bits per second to more than 500 million bits per second.
- Wireless is also a factor in network topology. Although it does not physically connect, it connects to network devices (nodes) logically. It is still applicable in network topology as it can transmit and receive data and the design will be impacted as such.
Examples of Network Topology
Here we begin our journey to understanding the basics of network topology as it relates to network fundamentals.
A bus network topology is when every network node is directly connected to a main physical cable.
In a ring topology, network devices are connected in a physical loop, so each network device has exactly two neighbors. Adjacent neighbors are connected directly; non-adjacent node pairs are connected indirectly through multiple network devices.
In a star network topology, all network devices are connected to a single, central hub and each network device is indirectly connected through that hub.
A mesh topology is defined by overlapping connections between network devices. You can create a full mesh topology, where every network device in the network is connected to every other network device. This is a full mesh topology.
You can also create partial mesh topology in which only some network devices are connected to each other and some are connected to the network devices with which they transfer the most data. Full mesh topology can be expensive and time-consuming to execute, this is reserved for networks that require high redundancy. Though partial mesh provides less redundancy but is more cost effective and simpler to execute.
