VLR PURGING AND TDD STATUS

Dear All;

Caan you pls tell me the command that can be fired in server to get the status of VLR PURGING period? Means i should come to know the Time period given for Purging period.

What is meant by TDD?

Is LOITERING same as Purging Period?

If you are setting a high purging period you will get a high VLR…is it?

So pls letme knw
1.command that can be used for displaying the Purging period status?
2.TDD?