Was initially interviewed on the phone with 3 people. Questions varied from stuff I did for my dissertation to wireless technologies like 802.11, with an emphasis on C++. I got through the phone interview pretty easily and was invited on-site. First I had to do a presentation for 45 mins, followed by 6 in-person interviews. Questions were mostly focused on C++, with a few brain-teasers. I knew that I had done the interview well, and was offered the job a week later.