Question

Explain CSMA/CD back off algorithm briefly. Using the CSMA/CD back-off algorithm, compute the conditional probabilities of two nodes A and B having collision numbers as 1 and 3 respectively. Illustrate the probability of A’s and B’s chance for winning the collision and the chance for a no collision. need to know how Need to know p(a) and p(b) and p(c)

Answer 1

CSMA/CD backoff algorithms:-

We need algorithm so that after 1st collision,stations involved in collision doesn't starts transmitting the packet again at the same time thereby reducing the number of collisions.

Now,collision number = number of times a packet has attempted to send their packet.

Say if collision number = 1,then its their 1st attempt.

if collision number = k,then according to back off algorithm we need to choose a random number between (0,2^k-1) now,after that they wait for time = k * T_slot .if they(station involved in collision) didn't generate the same random number then they will not be involved in collision.

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