Choose the right sequence of stages for data transmission using CSMA/CD.
A. If the channel is clear, the sender sends the data.
B. The sender senses the channel for activity.
C. The sender waits for a random back off time before retransmitting.
D. Collision detection occurs if two devices transmit at the same time.
Choose the correct answer from the options given below:

Correct option is B

The CSMA/CD (Carrier Sense Multiple Access with Collision Detection) protocol follows a specific sequence for transmitting data.
Step 1: The sender senses the channel — B
Before transmitting, the sender first checks whether the communication channel is busy or idle.
B. The sender senses the channel for activity.
Step 2: If the channel is clear, transmit — A
If the channel is found to be idle, the sender transmits the data.
A. If the channel is clear, the sender sends the data.
Step 3: Detect a collision — D
While transmitting, the sender continues monitoring the channel. If two devices transmit simultaneously, their signals interfere, resulting in a collision.
D. Collision detection occurs if two devices transmit at the same time.
Step 4: Random backoff — C
After detecting a collision, the sender waits for a random backoff period before attempting retransmission.
C. The sender waits for a random backoff time before retransmitting.
Information Booster
1. CSMA → Carrier Sense Multiple Access.
2. CD → Collision Detection.
3. The sender first senses the channel.
4. If the channel is idle, it transmits.
5. During transmission, it detects collisions.
6. After a collision, it waits for a random backoff time and retransmits.
Additional Knowledge
The basic CSMA/CD sequence can be remembered as:
Sense → Transmit → Detect Collision → Backoff