er being taught about one's density while Jeff drove us down Interstate 80, scribbling waveforms on a pad on his knee while I tried not to be visibly frightened. Thanks also for proof- reading some of my telecom chapters. There is no one I would trust more to do SO. I would like to thank Mike Stevens for help with readability and for some of the more colorful memories that have been included in this book. His help with PIX firewalls was instrumental to the completion of the first edition. You should also be thankful that I haven't included any pictures. I have this one from the Secaucus data center. I would like to thank Peter Martin for helping me with some subjects in the lab for which I had no previous experience. And I'd like to extend an extra thank you for your aid as one of the tech reviewers for Network Warrior-your comments were always spot-on and your efforts made this a better book. I would like to thank another tech reviewer, Yves Eynard: you caught some mistakes that floored me, and I appreciate the time you spent reviewing. This is a better book for your efforts. would like to thank Sal Conde and Ed Hom for access to 6509E switches and modules. I would like to thank Michael Heuberger, Helge Brummer, Andy Vassaturo, Kelly Huffman, Glenn Bradley, Bill Turner, and the rest of the team in North Carolina for allowing me the chance to work extensively on the Nexus 5000 platform and for lis- tening to me constantly reference this book in daily conversation. I imagine there's nothing worse than living or working with a know-it-all writer. I would like to thank Christopher Leong for his technical reviews on the telecom and VoIP chapters. I would like to thank Robert Schaffer for helping me remember stuff we'd worked on that I'd long since forgotten. I would like to thank Jennifer Frankie for her help getting me in touch with people and information that I otherwise could not find. Preface I would like to thank Mike Loukides, my editor, for not cutting me any slack, for not giving up on me, and for giving me m