U did not mention here what background u have ! Have u any experience in job market. If yes, what kind of job u have done / currently doing…. Why r u planning to do so.
However, for ur information, There r 5 types of certification in CCNA course curriculum like as Entry, Associate, Professional, Expert, and Architect. The lowest level of certification is CCENT which covers basic networking modules. After that, u may join for CCNA, under this mainly u get the idea and hands on experience on Routing & Switches. Though there r also voice;security etc.etc. Next level is CCNP (which u mentioned). It mainly focuses on QoS / broadband / VPN or some security-oriented features.
Cisco Certified Design Professional CCDP is a advanced level of networking programme, which gives u high technology on the same. And Cisco Certified Network Professional-Security, the name refers as Security in Routers, Switches, Networking devices / appliances, as well as deploying, supporting and troubleshooting Firewalls, VPN etc.etc….