Collision avoidance (networking)

In computer networking and telecommunication, collision-avoidance methods try to avoid resource contention by attempting to avoid simultaneous attempts to access the same resource.

Collision-avoidance methods include prior scheduling of timeslots, carrier-detection schemes, randomized access times, and exponential backoff after collision detection. In addition to the collision-avoidance methods mentioned, another important technique commonly used in computer networking and telecommunication to avoid resource contention is the implementation of protocols such as Carrier Sense Multiple Access with Collision Detection (CSMA/CD) and Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA).

CSMA/CD is a protocol used in Ethernet networks to regulate access to the network medium. Before transmitting data, a device using CSMA/CD first listens to the network to check if it is idle. If the network is busy, the device waits for a random amount of time before attempting to transmit again. If a collision is detected during transmission, the devices involved stop sending data and implement a backoff algorithm to avoid further collisions.

CSMA/CA is a protocol commonly used in wireless networks to avoid collisions. With CSMA/CA, devices listen to the wireless channel before transmitting data. If the channel is clear, the device can proceed with transmission. If the channel is busy, the device waits for a random amount of time before attempting to transmit. Additionally, devices may use Request to Send (RTS) and Clear to Send (CTS) messages to reserve the channel before transmitting data, further reducing the likelihood of collisions.

These protocols and methods are essential in ensuring efficient and reliable communication in networked environments by minimizing the impact of collisions and resource contention, ultimately improving the overall performance and scalability of the network.

See also

• Carrier sense multiple access with collision avoidance
• Polling
• Collision domain

External links

• Lenzini, L.; Luise, M.; Reggiannini, R. (June 2001). "CRDA: A Collision Resolution and Dynamic Allocation MAC Protocol to Integrate Date and Voice in Wireless Networks". IEEE Journal on Selected Areas in Communications. 19 (6). IEEE Communications Society: 1153–1163. doi:10.1109/49.926371. ISSN 0733-8716.