I thought I did pretty well with two of the three people. I wasn't asked any programming or puzzle questions. Mostly, I was asked to explain various aspects of the projects I worked on. There were some questions of an engineering design nature. I was disappointed that I did not remember the difference between a route reflector and a route server, and that I didn't remember what an autonomous system confederation was, but I responded that I knew where to go to get that information, as you can see. (Arguably, I did not have to deal with either of these in my last job.) I also didn't recognize the name Halabi – the author of a Cisco Press textbook on network architecture, but there are so many BGP-related publications that it's hard to keep track of all of them, let alone read them.
I felt confident and comfortable talking about the performance testing of OpenBGPD and Bird that I had done. In general, I think I do better on interviews when I can talk about something that I worked on and discuss the implementation, engineering tradeoffs, etc. Also, I think spending time thinking about the projects I worked on and of questions that I might be asked about them also helps.
If I get the job, I expect to be quite busy coming up to speed on their products (possibly busy enough to need to take time off from chorus and/or dancing for a while). If I don't get the job, at least I feel like the type of interview preparation I'm doing will eventually land me a job, provided that market conditions support it, and I get a fair chance to prove myself. What concerns me is what I will do if market conditions don't support the type of work I've done well in, and want to do. I seem to run into more problems when applying for "web" or "social" jobs, especially those that require algorithms to be memorized and such. The dilemma is that there are more of those positions available, but there are more people competing for them, and I don't have much experience doing that type of work. That plus the idiosyncratic nature of interviews for those positions means they are more difficult for me to get.