CCNA is a beginning-level certification that provides a solid foundation in Cisco networking. Cisco’s certification programs certify the competence professionals in routing, switching and connectivity. CCNA requires passing two exams - 640-822 and 640-816. This credential can be a stopping point, as you've become qualified in Routing and Switching, or you can set yourself for CCNP and other Professional-level certifications.
A CCNA certification is valid for 3 years.
For CCNA, you must have at least six months experience in networking. It is meant for anyone involved in implementing or supporting networks.