I was wondering how QC works internally for back tests, live papaer trades, and real live trades. I have a few questions about that:

1- from what I understand the feed providers usually provide Tick data and not directly Second data. So when an algo uses Second resolution, is it LEAN that is converting the tick data into second data by fill forward? (is that the correct term?) or the feed provider actually provides consolidated/aggregated live Second data?

2- where does the data feed for QC paper trade come from? is it IB? or IB's default data feed? or some other sources?

3- do the feeds for QC paper trading, IB paper trading, and IB live trading come from different sources?

4- do historical data and live feed data come from the same source?

5- does LEAN clean up suspecious data before calling OnData? or passes those to OnData as well?

6- does historical data include the suspecious data? or what we test with is already cleaned up?


Thanks a lot