Study permit:

A document issued by the Canadian government that allows foreign students to study at designated learning institutions in Canada. The application to attain this permit must be applied before travelling to Canada with proper documentation. Study permit should not be confused with Visa; it doesn’t allow you to enter Canada without a visitor visa or electronic travel authorization. 

SDS:

To get your student permit faster, Cannadian government has launched a new rule of Study Direct Stream. For which all you need to do is give your biometrics as soon as possible and meet all the eligibility requirements. SDS now provides its services on an average of 20 days based on the location where you live.

Study without permit:

For foreign students to enter and remain in Canada to attend a course or program of study for not more than 6 months; no study permit or student visa is required for the same. The course of study can be part time or full time but it must be completed within the authorized period i.e 6 months upon entry.

Renewing study permit:

To keep studying in Canada and extend your study permit; one should apply at least 30 days before its expiry. The study permit can’t be extended beyond the expiry date of your passport so make sure that the passport is not expired at the same time. One benefit that you will own of applying before the expiry of your permit is that, until a decision is made by the Canadian government, you are allowed to stay in Canada under the same conditions as your present permit allows you to.