The CCIE is comprised of a written exam and a practical exam. Upon passing the written exam, the candidate has eighteen months to take the lab exam. If the first attempt is unsuccessful the candidate has three years from the date the written exam was passed to successfully complete the lab. If a candidate does not pass the CCIE lab in that time, they must pass the CCIE written exam again before making additional attempts at the CCIE lab exam. As many attempts can be made to pass the lab exam for up to three years after passing the written, so long as the first attempt is within 18 months.
There are no formal prerequisites for the CCIE exam, but Cisco recommends one has at least 3–5 years experience in networking before attempting to become a CCIE. It is possible to hold multiple CCIE certifications. This is done by passing both the written and the lab exam in a particular track.