All have to pass the CCIE written test before they can take the lab lab test. If you don't pass the written exam you have to continue to take the written exam, there is no limit to the number of times you can take the written exam, but each written exam needs to be separated by 72 hours between exams.After passing the CCIE written exam, candidates have to take the CCIE lab lab exams within the validity period of the CCIE written exams.The validity period of the CCIE written exams is 18 months, and when you have passed the CCIE written exams you have to make sure that you take at least one CCIE lab lab exam in the 18 month period. Take the CCIE lab exam at least once, and thereafter take the lab exam at least once every 12 months to keep the written exam score valid. However, there is a time limit, and if a candidate is not able to pass the lab exam within three years of passing the written exam, then they will need to retake and pass the written exam to be eligible to register for the lab exam again. In addition, all candidates have a minimum interval of 30 days between lab exams, which should be counted from the first day of the previous exam. In other words, after the CCIE written exam you can make an appointment to take the lab lab exam. If you still need to prepare for the CCIE lab exam, then you also need to complete a lab exam within 18 months of passing the written exam. Otherwise, you will have to retake the CCIE written exam again.