CCNA is a beginning-level certification that aims to provide a solid foundation in Cisco networking. Cisco’s certifications certify the competence of networking professionals in routing, switching and connectivity. CCNA has two exams - 640-822 and 640-816. This credential qualifies you in Routing and Switching. You can then set yourself for a Professional-level certification. A CCNA is valid for 3 years.
For CCNA, you must have six months experience of working with networks. You should be familiar with the TCP/IP suite of protocols, and be able to configure networking on a PC within a workgroup environment. A CCNA professional should be able to manage simple networked and internetworked environments incorporating routers and switches.