Submission of resignation letter is the Resignation or Notice date?

If any candidate submit his resignation letter on a particular date, that date will be his resignation or notice date?
Please suggest.

The letter of resignation also amounts to notice and there is no need for a separate notice to be given. Many a times the resigning employee gives the date when he would like to be relieved , so the notice given is clearly calculable. Where the employee wants to be relieved forthwith, it means there is no notice and notice period pay can be recovered.