I applied for two positions online. I received an email from HR to set upan initial phone screen. A few days later an engineer called back at the appointed time, and we chatted for half an hour or so. A few days after that, HR called to say that they didn't think I was a fit for that particular position, but that they had forwarded my resume to another department. I repeated the process with a new engineer for a QA lead position. He asked a lot of questions about general QA practices, time management, networking, Linux, and circuit board components.
They then called back to set up a 4-hour interview at F5's Seattle office.
The interview consisted of a series of 5 45-minute interviews with various team members. Some of the interviews were by phone to off-site locations. I met with 3 engineers and two managers. They mostly asked me to tell stories about various things I had done in the past (e.g. test systems I'd designed, etc.) However, one of the engineers had a couple of great questions in which he described situations where something was not working and he wanted me to trouble-shoot it. For example, two computers are connected by two network cables on a switch, but neither of them can ping the other - what could be wrong?
The two managers were not very technical, and unfortunately they did not communicate the purpose of their groups very well. In particular, I did not connect very well with the hiring manager, although I'm fairly confident that I passed the technical aspects of the interviews.
HR said that they would call me with a yes-or-no answer the following week. Two weeks later I received an email (nicely worded) that said that the manager had chosen somebody else for this job.