visa for parents ( dependant visa, not visitors)

Hi guys, I need your help please with thsi one.
I have just received my Tier 1 extensioon for 3 years. I would like to bring my parents to me as my dependants. My sister is married in another city ( and is not financially responsible for them ). My parents have been to UK as visitors for 3 times.

Could you please let me know if they get this visa, will they be able to stay with me for 6 months and stay in India for 6 months or so? I do not think at this time they would like to settle in UK for good. I could not see any obvious time restriction on this visa.

Any advise will be highly appreciated. Thanks

U cannot sponsor parents as dependants unless u have ILR or better.