What would be the major licensure difference between state and national level according to the NBCC?

This a discussion question that has to be 150-200 words

Please take time to review the National Board for Certified Counselors (NBCC) website to be able to respond to this discussion question. Website link: http://nbcc.org

What would be the major licensure difference between state and national level according to the NBCC? In addition, could a counselor practice in their state only a national certification? What is the purpose of a national certification?