Based on past experience, CCIE lab exams are usually zero-tolerance, meaning that a candidate's error in any of the tasks may result in the task being ruled a fail. Therefore, in order to pass the exam, candidates need to do their best to avoid errors and complete all tasks within the allotted time. During the exam, markers assess the candidate's configuration against a series of marking criteria. These marking criteria typically include aspects such as correctness, completeness, reliability and efficiency. If a candidate makes a mistake in their configuration, it may affect the correctness and completeness of the tasks, which may result in failing the exam. In conclusion, the CCIE lab exam is a very rigorous exam that requires candidates to avoid mistakes as much as possible throughout the lab process. In order to better prepare for the exam, it is recommended to attend relevant training courses, practice and prepare thoroughly, and ensure that you have a clear understanding of the exam requirements and scoring criteria.