http://www.cisco.com/web/learning/certifications/professional/ccnp_voice/recert.html
Cisco Professional-level certifications (CCNP, CCNP Wireless, CCDP, CCSP, CCNP Security, CCNP Voice, CCIP, CCNP Service Provider, CCNP Service Provider Operations, and CCNP Data Center) are valid for three years. To recertify, pass ONE of the following before the certification expiration date:
- Pass any current 642-XXX Professional-level exam, or
- Pass any current CCIE Written Exam, or
- Pass the current CCDE Written Exam OR current CCDE Practical Exam, or
- Pass the Cisco Certified Architect (CCAr) interview AND the CCAr board review to extend lower certifications
