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HYBRID TOPOLOGY AND ITS ADVANTAGES AND DISADVANTAGES

DIFFERENCE BETWEEN CSMA/CD AND CSMA/CA

DIFFERENCE BETWEEN CSMA/CD AND CSMA/CA

CSMA/CD:
Carrier sense multiple access with collision detection (CSMA/CD) is one of the most popular access methods, with CSMA/CD, every host has equal access to the wire and can place data on the wire when the wire is free from traffic. If a host wishes to place data on the wire, it will โ€œsenseโ€ the wire and determine whether there is a signal already on the wire. If there is, the host will wait to transmit the data; if the wire is free, the host will send the data, as shown in Figure 1.

Figure 1: A host “sensing” the wire to see if it is free of traffic.

The problem with the process just described is that, if there are two systems on the wire that โ€œsenseโ€ the wire at the same time to see if the wire is free, they will both send data out at the same time if the wire is free. When the two pieces of data are sent out on the wire at the same time, they will collide with one another, and the data will be destroyed. If the data is destroyed in transit, the data will need to be retransmitted. Consequently, after a collision, each host will wait a variable length of time before retransmitting the data (they donโ€™t want the data to collide again), thereby preventing a collision the second time. When a system determines that the data has collided and then retransmits the data, that is known as collision detection.

 To summarize, CSMA/CD provides that before a host sends data on the network, it will โ€œsenseโ€ (CS) the wire to ensure that the wire is free of traffic. Multiple systems have equal access to the wire (MA), and if there is a collision, a host will detect that collision (CD) and retransmit the data.

CSMA/CA:

Carrier sense multiple access with collision avoidance (CSMA/CA) is not as popular as CSMA/CD and for good reason. With CSMA/CA, before a host sends data on the wire, it will โ€œsenseโ€ the wire as well to see if the wire is free of signals. If the wire is free, it will try to โ€œavoidโ€ a collision by sending a piece of โ€œdummyโ€ data on the wire first to see whether it collides with any other data. If it does not collide, the host in effect assumes โ€œIf my dummy data did not collide, then the real data will not collide,โ€ and it submits the real data on the wire.

DIFFERENCE BETWEEN CSMA/CD AND CSMA/CA

CSMA/CDCSMA/CA
The full form of CSMA/CD is carrier sense multiple access with collision detection.The full form of CSMA/CA is carrier sense multiple access with carrier avoidance.
CSMA/CD detects the collision, and once the collision is detected, then it stops continuing the data transmission.CSMA/CA does not deal with the recovery of the collision.
Wired installation is used in a CSMA/CD to detect the collision.Wireless installation is used in a CSMA/CA as it avoids collision. Therefore, it does not need a wired network.
An 802.3 Ethernet network uses CSMA/CD.An 802.11 ethernet network uses CSMA/CA.
CSMA/CD takes effect after the occurrence of a collision.CSMA/CA takes effect before the occurrence of a collision.

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Aanchal Gupta

Welcome to my website! I'm Aanchal Gupta, an expert in Electrical Technology, and I'm excited to share my knowledge and insights with you. With a strong educational background and practical experience, I aim to provide valuable information and solutions related to the field of electrical engineering. I hold a Bachelor of Engineering (BE) degree in Electrical Engineering, which has equipped me with a solid foundation in the principles and applications of electrical technology. Throughout my academic journey, I focused on developing a deep understanding of various electrical systems, circuits, and power distribution networks.

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