SceneKit animate node along path

I have a box node

_boxNode = [SCNNode node];
_boxNode.geometry = [SCNBox boxWithWidth:1 height:1 length:1 chamferRadius:0];
_boxNode.position = SCNVector3Make(0, 0, -2);
[scene.rootNode addChildNode:_boxNode];

I have a path

CGPathRef path = CGPathCreateWithEllipseInRect(CGRectMake(-2, -2, 4, 4), nil);

I want to have my box travel along my path.

How do I do this in SceneKit?