While knowing how to design electronic hardware is the key competency of a senior hardware engineer, knowing the theory behind the design and how each of the functions of the components is critical. This provides the engineer with the information they need to quickly develop designs that will function as intended. Interviewers at Cisco will ask you about theoretical situations, practical aspects of your job, and real-life scenarios you will likely encounter once hired. Anticipating these and preparing your answers in advance will help you perform well during the interview with Cisco.