Bring the cranberry soda and sugar to a boil in a large pan.
Once you reach a boil add the cranberries and return to a boil. Turn the heat down until the mixture is boiling gently. If you let the mixture boil too hard you may end up with a mess on your hands.
Let it boil for 10 minutes or until all the berries have burst and the sauce has thicken.
If you wish to make whole cranberry sauce, just pour it into a bowl. For jellied sauce: push the mixture through a sieve to strain out the skins.