Cisco offers three levels of certifications: (a) Associate, (b) Professional and (c) Expert. Associate level can be considered as entry-level certifications, which means that a candidate should display a working knowledge of basic networking concepts. Professional certifications are more advanced than associate. This is the reason why if you are interested in taking up a Cisco Certified Network Professional (CCNP) exam, you have to gain a Cisco Certified Network Associate (CCNA) certification first. The rules are just plain and simple as candidates work their way up to Expert level, the highest in the Cisco certification hierarchy.
Candidates have two options in getting a CCNA certification. They can either take the two-test option (ICND1 640-822 and ICND2 640-816) to allow them to focus on certain subjects, or the shortcut single test option (CCNA 640-802). Taking both ICND1 and ICND2 exams will costs a candidate a total of US $250 (US $125 for each) and US $150 for the full CCNA exam. Passing the ICND1 alone entitles the candidate of a Cisco Certified Entry Networking Technician (CCENT) certification. The CCNA certification is available only at Pearson VUE testing centers and is valid for three years only. The candidate then has the option to recertify, or take a professional (CCNP) or expert-level certification (CCIE).
CCNP, on the other hand, can be achieved by passing three or four exams, depending on what path the candidate chooses. The four-exam option includes the following: 642-901 BSCI, 642-812 BCMSN, 642-825 ISCW and 642-845 ONT, while the three-exam option has the following: 642-892 Composite, 642-825 ISCW and 642-845 ONT. Recertification is also required every 3 years, wherein one can choose to stay as CCNP or take a chance on the CCIE certification.