"Mesh" should be an interface or an abstract class?

[lucky6969b]

class IMesh
{
 public:
            virtual void update(float dt) = 0;
            virtual void render() = 0;
};

or

class AMesh
{
public:
            virtual void update(float dt) = 0;
            virtual void render() = 0;
public:
           D3DXFRAME *m_Root;
};

Any advices please?
Thanks
Jack