Heavy vs light infantry

I would like to know the difference between:

  • light infantry with sword, hauberk and shield;
  • heavy infantry with sword, hauberk and shield.
    Anyone knows?

Armor! The difference in armor!

How much? Because if they both use hauberks the armor is the same…or not?
I pay a lot more for heavy so…there must be a difference even if they equip the same things.

Who uses plate armour then?

Heavy infantry can use hauberks if you don’t have plate. In this case which is the difference between light vs heavy inf?