I met a representative from A10 Networks at a career fair and I had a phone interview few days later. I got an on-site interview which I talked with 6 people for 6.5 hours. It was the longest interview I did and it was pretty tiring.

Did a resume drop with A10 at a career fair, and was emailed a few days later to set up a phone interview later in the week. Started with a brief phone interview with one of the engineers where they scoped me out and asked me some very general questions, while also explaining what type of position I was interviewing for and what the job description entailed. Phone interview was about 1 hour. An on-site was schedule via email not too long afterwards, for a week later. Their interview process is very... arduous. I was told to expect the entire process to take 4 hours (3-7PM). It basically consisted of me sitting in a room and various employees coming into the room and interviewing me for about 30 minutes each. Some employees were courteous and asked interesting questions. Others were somewhat eccentric and didn't seem like they really wanted to be there. I was interviewed by other support engineers, the Director of the support division, and a VP of engineering. I definitely enjoyed some of the interviews, but others seemed very dry and pointless. A lot of general/behavioral questions were asked, and some semi-technical questions were asked (experience with programming languages, how would you approach this problem, etc), as well as some random brain teaser/logic puzzle questions. Portions of the interview were also devoted to "selling" the company to me.