CSMA/CA protocol in Computer Networks - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does CSMA/CA stand for?

CSMA/CA stands for Carrier Sense Multiple Access with Collision Avoidance. It is a network protocol used to avoid data collisions in wireless networks.

intermediate

How does CSMA/CA differ from CSMA/CD?

CSMA/CA tries to avoid collisions before they happen by waiting and signaling, while CSMA/CD detects collisions after they occur and then stops and retries sending data.

beginner

Why is collision avoidance important in wireless networks?

In wireless networks, devices cannot detect collisions easily because they can't listen while sending. Collision avoidance helps reduce data loss and improves network efficiency.

intermediate

What is the role of the RTS/CTS mechanism in CSMA/CA?

RTS (Request to Send) and CTS (Clear to Send) are messages used to reserve the channel before sending data, helping to avoid collisions especially in networks with hidden nodes.

beginner

What happens if a device senses the channel is busy in CSMA/CA?

If the channel is busy, the device waits for a random backoff time before checking again. This reduces the chance that multiple devices send data at the same time.

What does the 'CA' in CSMA/CA stand for?

A Collision Avoidance

B Collision Access

C Carrier Access

D Carrier Avoidance

CA means Collision Avoidance, which helps prevent data collisions before they happen.

Which mechanism is used in CSMA/CA to reserve the channel before sending data?

A ACK/NACK

B DNS

C ARP

D RTS/CTS

RTS (Request to Send) and CTS (Clear to Send) messages help reserve the channel and avoid collisions.

Why can't wireless devices easily detect collisions during transmission?

A Because devices cannot listen while sending

B Because of network congestion

C Because wireless signals are too weak

D Because of IP addressing

Wireless devices cannot listen to the channel while sending data, so they can't detect collisions directly.

What does a device do if it senses the channel is busy in CSMA/CA?

A Waits a fixed time and retries

B Waits a random backoff time before retrying

C Sends data immediately

D Switches to another channel

The device waits a random backoff time to reduce the chance of collision when retrying.

CSMA/CA is mainly used in which type of networks?

A Wired Ethernet networks

B Satellite networks

C Wireless networks

D Optical fiber networks

CSMA/CA is designed for wireless networks where collision detection is difficult.

Explain how CSMA/CA helps avoid collisions in wireless networks.

Think about how devices check the channel and communicate before sending data.

Describe the difference between CSMA/CA and CSMA/CD protocols.

Focus on when collisions are handled and the type of network.