Mediumåtkomst

Mediumåtkomst, also known as medium access control, refers to the methods and protocols used to manage how multiple devices or users share a communication channel or network resource. This concept is fundamental in telecommunications, computer networking, and wireless communication systems, where multiple entities may compete for access to a shared medium such as an Ethernet cable, radio frequency, or bus topology.

In wired networks, medium access control is often handled by protocols like Carrier Sense Multiple Access with Collision Detection (CSMA/CD), which was used in early Ethernet networks. Devices listen to the network before transmitting to avoid collisions, where two or more devices send data simultaneously. If a collision occurs, the devices wait a random amount of time before retrying. Modern Ethernet uses full-duplex communication, reducing the need for collision detection by allowing simultaneous two-way data transfer.

In wireless networks, medium access control is more complex due to the shared nature of radio frequencies. Protocols such as Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA), used in Wi-Fi (IEEE 802.11), employ a handshake process to coordinate transmissions and minimize interference. Devices check for activity on the channel before transmitting and may use acknowledgments to confirm successful data delivery.

Medium access control ensures efficient and fair sharing of network resources, preventing congestion and optimizing performance. Different protocols are designed for specific use cases, balancing factors like latency, throughput, and fairness. Advances in technology continue to refine these methods, supporting higher data rates and more reliable connections in modern networks.