Топологии сетей | Курс "Компьютерные сети"

Introduction to Computer Network Topologies

In this lecture, we will explore the topic of computer network topologies. Topology refers to the way computers are connected in a network. There are several basic topologies that we will discuss.

Basic Network Topologies

• Full Mesh Topology:

• Every device in the network has a direct connection to every other device.

• Advantages: Direct channel to each device, data can always be transmitted.

• Disadvantages: Requires many connections and network adapters for large networks.

• Cellular Topology:

• A variation of full mesh topology where some connections are removed.

• Star Topology:

• Computers are connected to a central device (e.g., switch or hub).

• Data transmission between computers is done through the central device.

• Ring Topology:

• Each computer is connected to two neighboring computers forming a ring.

• Data is transmitted around the ring from one computer to another.

• Tree (Hierarchical) Topology:

• Both computers and networking devices form a tree-like structure.

• Data transmission requires passing through intermediate devices.

• Bus (Linear) Topology:

• All computers are connected to a shared communication medium (e.g., coaxial cable).

• Data transmitted on the medium is accessible by all connected computers.

Mixed Network Topologies

• Hybrid/Mixed Topologies:

• Large networks often use a combination of different basic topologies.

• For example, a network may have a ring topology in one segment and a star topology in another.

Physical vs Logical Topology

• Physical Topology:

• Describes how devices are physically connected to form the network.

• Examples include star, ring, and bus topologies.

• Logical Topology:

• Refers to the rules governing signal propagation in the network.

• Ethernet is an example where physical topology can be different from logical topology.

Conclusion

• Ethernet Technology:

• Classic Ethernet uses a physical star topology but has a logical bus topology.

• Switched Ethernet:

• Modern Ethernet technology uses switches with a physical star topology and logical full mesh connectivity.

• Wireless (Wi-Fi) Networks:

• Wi-Fi networks have no physical connections and rely on radio signals for data transmission.

• The logical topology is typically a shared bus where all computers within range can receive transmissions.

• Summary:

• Computer network topologies define how devices are connected in a network.

• Basic topologies include full mesh, cellular, star, ring, tree, and bus.

• Real-world networks often use mixed or hybrid topologies combining different basic topologies.