This is an operational question. Interviewers will ask questions like this one to gain an understanding of how you go about doing your job. Operational questions are best answered directly and briefly. You should also anticipate follow-up questions once you provided the interviewer with your answer.
"Throughout my career, I have strived to provide 'five-nines' uptime reliability. I accomplish this by continually monitoring the network using utilities and tools available for this purpose. One helpful technique is aggregating these tools into a single dashboard, which provides all the information I need about the network's status and potential issues. If a problem does occur, there are several different techniques I can use to identify the error and fix it. An example of this is tracerouting, which identifies network bottlenecks."