There were two interviews. For both interviews, I thought the person sounded interested in speaking with me and seeing what I knew.
The first interview began by asking personal questions, such as if you're able to work here and why you're interested in SIG. It then went onto basic technical questions (What port number is [X]? What Linux command does [X]? Describe the TCP 3-way handshake.).
The second interview was over 1 week later. It was all technical questions, which were more advanced than in the first interview, and asked you to explain or describe your answer in as much detail as possible.