The IIHS rules incorporate the rules of the IIHF by reference. Any rules not expressly provided for in the IIHS shall be subject to the provisions set forth in the IIHF Rule Book.
Here is a summary that includes the most relevant:

• Ice Hockey Nets
• Stilmat Puck & Floor
• Offside
• 2 Referees per game
• 2 periods
• Players per team: Max (14 skaters + 2 goalies) , Min (8 skaters + 1 goalie)

For a more comprehensive set of rules, please refer to the IIHS regulations guidelines and rules document.