What is the difference between 1- persistent csma and p- persistent csma?
Answers
1-persistent CSMA:-
1-persistent CSMA is fiery transmission algorithm.
When transmitting node is prepared to transmit it senses the transmission medium for idle.busy.
If idle then it transmits immediately.
Busy then it senses the transmission medium consistently till it becomes idle and then transmits the message unconditionally.
In a collision the sender waits for random period of time and tries the same process again.
1-persistent CSMA is used in CSMA/CD systems (Ethernet).
p-persistent CSMA:-
The link between 1-persistent and non-persistent CSMA access modes is the p-persistent CSMA.
When the transmitting node is prepared to transmit data it senses the transmission medium for idle/busy.
If idle then it transmits immediately.
Busy then it senses the transmission medium consistently till it becomes idle then transmits with probability (p). If the node does not transmit it waits till the next available time span.
If the sending medium is not busy it sends again with the same probability (p).
This probabilistic hold-off occurs again and the frame is finally sended when the medium is found to become busy.
Afterwards the node repeats the whole logic cycle again.
p-persistent CSMA is used in CSMA/CA systems (Wi-Fi, packet radio systems).