Counting Of Notice Period Days In Case Of Resignation

Dear seniors,
at times of leaving organisation, an employee has to serve the notice period. my question is, in general from when this period starts or calculated. is it from the date of acceptance of resignation or from the date of resignation (the day employee writes and submit his/her resignation).
Please throw some light on it.
thanks & regards
N

Dear Sharmaneesu,
Actually notice period starts from the day an employee resigned, still nowadays many company count the notice period from the date the resignation is acknowledged/accepted. This happens mainly in IT Sectors.

Thanks Mahesh,
but I still feel that if it is just acknowledgement, then it is OK. what about acceptance of it. I have experienced a lot that, in many cases, either authorities accept or keep silent on it. if they don't wish to accept as it was not desired or not in favour of organisation/work, so they don't revert/acknowledge.
anyways, thanks to you. you mean ideally it should count from the day an employee resigned.
Thanks!
N