My overall perception of the interview is that it was quite reasonable. Mostly technical, pertinent questions which one should know if they have engaged in design work at that level. Position was supporting SONET related designs so it was expected to have some knowledge of SONET but more emphasis, and rightly so, was on design rather tahn nitty gritty details of the protocols or the specs. I personally am not that big a fan of behavioral questions for a purely technical position at least and was glad to see it that way.