The Cisco Certified Internetwork Expert (CCIE) certification consists of both written and lab exams. The written exam, which costs about US$315 for every attempt, is pre-requisite for the lab exam. Only when the candidates pass the written exam can they be qualified to take initial attempt for the lab exam in 18-month duration. In case the initial lab exam was failed, the candidates are given 3 years to complete the lab exam (starting from the date they have passed successfully the written exam). If the candidates have yet failed to pass the CCIE lab within this 3-year period, they would again be required to take and pass successfully the written exam before making further efforts in taking the lab exam. Candidates can make as many attempts possible to pass the CCIE lab exam (waiting time between attempts is one month) provided that they have first passed successfully the written exam. The CCIE lab exam, which is an 8-hour practical exam, currently costs about $1,400 per attempt. This lab exam intends to validate practice of theory learned by those who passed the written exam. Most CCIE takers undertake several attempts to pass. Although there are no formal requirements, Cisco recommends candidates to have at least 3?5 years of networking experience before trying to become genuine CCIE holders. Ten Cisco Lab Exam centers located nationwide offer CCIE, which include: Beijing; Bangalore; Brussels; Dubai; Hong Kong; Research Triangle Park, NC; São Paulo; Sydney; San Jose, CA; and Tokyo, Japan. Depending as which CCIE tracks the candidates desired to complete, there are cases wherein some tracks do not include lab exams nor available at all locations. Likewise, it is also possible for one to acquire multiple CCIE certifications by succeeding both written and lab exams in a specific track.