PERSISTS / SLOT TIME
To accomplish CSMA, TNC implements a specific technique using two variables called:
The process is very simple:
- When the channel is free the TNC generates a random number (between 0 and 255); if it is greater than PERSISTS, it will wait the SLOT TIME and that it will generate a random number again, if not it will start transmission.
If PERSISTS is 255 it will never be smaller than the random generated number so the TNC will transmit immediately after the channel gets free.