[Advaita-l] Taking sanyasa

[sreenivasa murthy]

Dear friends,
Has sanyasa to be taken up before taking up study of upanishadsor it has to be taken up after the successful completion of the 
study of Vedanta?
What is the existing sampradya for this in the present times?

Clarification for the above stated doubts is requested from the scholarly / learned members of this group.
With respectful namaskars,Sreenivasa Murthy