Networking - Miscellaneous - CSMA/CA vs CSMA/CD
CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) and CSMA/CD (Carrier Sense Multiple Access with Collision Detection) are two variants of the CSMA (Carrier Sense Multiple Access) protocol used in Ethernet networks. Here's a comparison between CSMA/CA and CSMA/CD:
CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance):
- Used in wireless networks, specifically Wi-Fi networks.
- Stations listen to the medium and wait for it to be idle before transmitting.
- Utilizes a virtual carrier sensing mechanism to avoid collisions in the wireless environment.
- Before transmitting, stations perform a Request to Send (RTS) and Clear to Send (CTS) handshake to reserve the channel and avoid collisions.
- Stations follow the rules of the Distributed Coordination Function (DCF) in the IEEE 802.11 standard.
- Provides collision avoidance by allocating time slots and prioritizing access based on a contention mechanism.
- Slower than CSMA/CD due to additional overhead for RTS/CTS exchanges and contention mechanisms.
- Designed to reduce the impact of collisions and improve the reliability of wireless transmissions.
CSMA/CD (Carrier Sense Multiple Access with Collision Detection):
- Used in wired Ethernet networks, such as Ethernet LANs.
- Stations listen to the medium and check for collisions before transmitting.
- If a collision is detected during transmission, stations stop transmitting and enter a backoff algorithm to reattempt transmission after a random delay.
- Relies on collision detection mechanisms to identify collisions and handle them accordingly.
- Stations follow the rules of the Ethernet standard (IEEE 802.3) for collision detection and collision resolution.
- Provides collision detection by monitoring the transmitted signal and comparing it to the received signal.
- Faster than CSMA/CA because it does not require the additional RTS/CTS handshake and contention mechanisms.
- Designed to detect and recover from collisions in wired networks.
