What steps were taken by Alauddin Khalji to prevent Mongol invasions?

Steps taken by Alauddin Khalji to prevent Mongol invasions were:

1. He repaired old forts and built a new garrison town named Siri for his soldiers.
2. He appointed his best generals on the frontiers.
3. He raised huge army. To keep the army efficient he introduced regular parades, inspection of troops and branding of horses.
4. To frighten the Mongols, the Mongol captives were tortured ruthlessly.
5. He started annual raids into the territory of the Mongols.