Ethernet primarily utilizes the Star topology in modern networks, although older Ethernet standards historically used the Bus topology.
Understanding the topology of a network like Ethernet is crucial for comprehending how devices connect and communicate. Network topology refers to the physical or logical arrangement of connections within a network. Ethernet, a widely adopted networking technology, has evolved significantly since its inception, and so have the typical topologies it employs.
Historical and Modern Ethernet Topologies
According to the provided reference, "Bus topology is used with Ethernet. The most used network topology is this one." The reference also states, "Bus and star topologies, as well as coax, twisted-pair, or fibre optic cable, are options."
This highlights that while Bus topology was indeed fundamental to early Ethernet implementations (like 10BASE5 or 10BASE2), where devices shared a single cable segment, modern Ethernet networks predominantly use the Star topology.
In a Bus topology:
- All devices are connected to a single shared communication line (the bus).
- Data packets are sent along the bus, and each device checks if the packet is addressed to it.
- Requires termination resistors at both ends of the bus.
- Collisions can occur if multiple devices transmit simultaneously, requiring collision detection and handling mechanisms (like CSMA/CD, which is part of the Ethernet standard).
- A break in the main bus cable can disrupt the entire network.
In a Star topology:
- Devices connect to a central hub, switch, or router.
- The central device manages communication between connected devices.
- More reliable; failure of a single cable typically only affects the connected device, not the entire network.
- Easier to troubleshoot and expand.
- The performance is generally better as communication is often managed by the central device, reducing collisions compared to a shared bus.
While the reference mentions Bus as being "most used," this likely pertains to a historical context or specific older standards. Contemporary Ethernet installations, particularly in LANs, overwhelmingly rely on switches in a Star configuration for improved performance, reliability, and manageability.
Ethernet Cable Options
The topology used often dictates or is dictated by the type of cabling. As the reference notes, Ethernet can operate over various cable types:
- Coax cable: Used in older Bus topology Ethernet (like 10BASE5 and 10BASE2).
- Twisted-pair cable: The most common cable type for modern Star topology Ethernet (e.g., Category 5e, 6, 6a, used in 10BASE-T, 100BASE-TX, 1000BASE-T).
- Fibre optic cable: Used for high-speed, long-distance Ethernet connections (e.g., 1000BASE-LX, 10GBASE-LR) often in backbone networks or connecting switches.
Summary of Ethernet Topology and Cable Options
Based on the reference and common practice, here's a quick overview:
| Topology Option | Common Usage | Typical Cable Type(s) |
|---|---|---|
| Bus | Older Ethernet standards (e.g., 10BASE5/10BASE2) | Coaxial |
| Star | Modern Ethernet networks (most common) | Twisted-pair, Fibre Optic |
In essence, while the Bus topology was foundational to early Ethernet and is mentioned in the reference as being used and potentially "most used" in that specific context, the Star topology connected via switches is the dominant form of Ethernet deployment today.
