Question

1.

A. How much data is affected if a collision occurs between two (2) network nodes using CSMA/CA?

B. Which Access Control Technique (CSMA/CD, CSMA/CA or Token Passing) is the most popular in a Ring network?

Answer 1

A. In CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance), when a collision occurs between two network nodes, the data involved in the collision is typically the data being transmitted by both nodes. The collided data packets become corrupted and need to be retransmitted.

The amount of data affected by the collision depends on the size of the data packets being transmitted and the timing of the collision. If the collision is detected early, only a small portion of the data packets may have been transmitted, resulting in less data loss. However, if the collision is detected late, a larger portion of the data packets may have already been transmitted, leading to more significant data loss.

B. In a Ring network, the most popular access control technique is Token Passing.

Token Passing is a method where a special control frame called a "token" circulates around the network in a unidirectional manner. Only the device holding the token has the right to transmit data. When a device wants to transmit data, it waits for the token to reach it, seizes the token, attaches its data to the token, and then releases the token back into the network. The token continues to circulate, and other devices can access the token when it reaches them.

Token Passing provides fair access to the network and ensures that only one device transmits at a time, reducing the chances of collisions. It also guarantees that every device gets a turn to transmit data, preventing any device from dominating the network.

CSMA/CD (Carrier Sense Multiple Access with Collision Detection) is more commonly used in Ethernet networks, where collisions are detected and managed through the CSMA/CD process. However, in a Ring network, Token Passing is more popular due to its advantages in fairness and collision prevention.

Answer 2

1) (A) If a collision occurs between two network nodes using CSMA/CA then the entire data to be transmitted by those two network nodes is affected. In that case the transmission needs to be restarted.

1) (B) the most popular access control technique in a Ring network is token passing.

Hope this helps.

Answer 3

A. In CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance), a collision occurs when two or more network nodes attempt to transmit data simultaneously. When a collision occurs, the affected data is the data that was being transmitted by the colliding nodes and any data that was transmitted before the collision detection.

In CSMA/CA, before transmitting data, a node listens to the network to check if the channel is idle. If the channel is busy, the node waits for a random period of time (known as the backoff time) before attempting to transmit again. This random backoff helps to reduce the likelihood of another collision occurring immediately after the first collision.

The amount of data affected by a collision in CSMA/CA depends on the time it takes for the colliding nodes to realize that a collision has occurred and stop transmitting. The longer it takes for the nodes to detect the collision, the more data will be affected.

B. In a Ring network, the most popular Access Control Technique is Token Passing. In Token Passing, a special control message called a "token" circulates around the ring, and only the node that holds the token is allowed to transmit data. When a node wants to transmit data, it must wait for the token to come to it. Once it receives the token, the node can transmit its data onto the network. After transmitting its data, the node releases the token, and it continues to circulate around the ring, allowing other nodes to access the network in a controlled and orderly manner.

Token Passing is well-suited for Ring networks because it ensures that each node gets a fair opportunity to transmit data, and it eliminates the possibility of collisions. This makes the network more efficient and reliable compared to CSMA/CD (Carrier Sense Multiple Access with Collision Detection), which is typically used in bus or Ethernet networks. In CSMA/CD, collisions can occur, and the network needs to handle collision detection and retransmission of data, which can lead to reduced network performance in large or busy networks.