# calculating the probability of a successful broadcast in p-csma protocol

am quite unsure with the following question. would appreciate your help with it:

in a 3 stationed p-csma network, where $$\p=0.3\$$, we know that in $$\t_0\$$ the network is restarted, the channel is quiet(idle) and in the 3 stations there is a frame ready to be broadcasted.

a)is it possible to calculate the probability of a successful broadcast in time $$\t_0\$$?

b)will the previous answer would've changed if the protocol was 0-CSMA(non presistent CSMA)?

my attempt:

a)shouldn't it be $$\P_A = (1-\frac{1}{N})^{N-1}\$$ and in our case $$\= \left(\frac{2}{3}\right)^2\$$? and since the result is less than one, so the stations can transmit?

b)now it just waiting a random amount of time and then retrying. i don't know how to calculate that

i feel that i am doing a mistake in both. would very much appreciate a correction and the right way to do so to learn.

thank you very much for helping me. tried to explain and elaborate as much as i can

• Inline equations on this website is $EQUATION$, you need a backslash ( \ ). Our website is different than other SE's on here. – KingDuken Apr 16 at 21:20
• thank you for explaining that to me. next time i will use that to appropriately write equations. thought it's a bug in my browser that it doesn't show math. could you please help me with the question though? – hps13 Apr 18 at 6:33