Well its certainly possible to have a situation where there are no "hot wars" anywhere at any one time. May be possible to have situation where for a while you also don't have colder/more limited conflicts. But its impossible to prevent that there would any wars forever. Wars would ignite sooner or later.

But can we have 100 years of no hot wars between nations? Eventually yes. Can we have 100 years of no cold wars? Not for ages, if ever.