No problem with it. But you need both parties to be rational and with a philosophy that respects individual rights.
Throughout history, most states were not that. Which means that if a state grew strong, it swallowed it's neighbors. Even today, there are some strong states which are trying to swallow it's neighbors. China, Russia, Iran.
Which means that even a rights respecting sate which is based on freedom must be orepito defend itself. It needs an army.
An anarchist state will need to create some sort of super state to maintain this army and create some sort of revenue to finance said army. Which will make it a non anarchist state.
That is one reason anarchist are not maintainable.
