According to the Buddha, how is one freed from suffering?

I'm a bit confused about how, according to the Buddha, one is freed from suffering. I have read that suffering is one of the marks of existence. So can one be freed from it at all? If it's an aspect of existing, is it just something to accept? So the freedom is in accepting the suffering? I have also read that suffering is only caused by ignorance of the nature of reality. So to be free what does one have to understand? - No-self and impermanence? - Or does it mean to be mindful and see how things are at this very moment? Notice the breath, and your feelings, including the painful ones?