CSMA/CD, which stands for Carrier Sense Multiple Access with Collision Detection, is a MAC (media access control) protocol. It specifies how network devices should react when two devices try to use the same data channel at the same time and experience a data collision.
In this article, we will look more into the CSMA/CD according to the GATE Syllabus for (Computer Science Engineering) CSE. We will read ahead to find out more about it.
Table of Contents
What is CSMA/CD?
The network protocol for carrier transmission known as CSMA/CD (Carrier Sense Multiple Access with Collision Detection) runs at the Medium Access Control (MAC) layer. The shared channel for communication is detected or heard, and transmissions are postponed until the channel is clear. By detecting transmissions from other stations, the collision detection technique finds collisions. When a collision is detected, the station immediately ceases transmission, broadcasts a jam signal, and thereafter waits for a random amount of time before retransmission.
Algorithms
The CSMA/CD algorithm are:
- The transmitting station determines whether the channel is busy or idle when a frame is ready.
- If the channel is occupied, the station waits till it is free.
- The station begins transmitting and continuously scans the channel for collisions if the channel is empty.
- The station begins the collision resolution mechanism when a collision is detected.
- After finishing frame transmission, the stations reset the retransmission counters.
The collision resolution algorithm are:
- In order to make sure that all other stations notice a collision, the station keeps transmitting the current frame for a predetermined amount of time while also sending out a jam signal.
- The station increases the retransmission counter.
- The station stops transmission if the allotted number of retransmission attempts has been used.
- In the absence of a restart main algorithm, the station waits for a backoff period, which is often a function of the number of collisions.
Illustration
The algorithms are summarised in the flowchart below:
- This technique does not lessen the number of collisions even though it can detect them.
- Large networks shouldn’t use it because the performance suffers rapidly as more stations are added.
Keep learning and stay tuned to get the latest updates on the GATE Exam, GATE 2023 along with GATE Eligibility Criteria, GATE Syllabus for CSE (Computer Science Engineering), GATE CSE Notes, GATE CSE Question Paper, and more.
