Ed Tittel worked as an instructor for Austin Community College from 1997 through 2003 and taught at Interop from 1996 to 2004. He is a Network Certified Professional, and works as a full-time freelance writer and consultant in Austin, TX. He has contributed to over 130 books on computing across a broad range of subjects, and is the author of numerous titles published by Course Technology. He also writes and blogs for numerous TechTarget.com and other Websites. Served as Developmental Editor for Global Support Content Operations at Hewlett-Packard. He is currently the technical writer and marketing contributor for Kount. Jeffrey L. Carrell is a network systems and security instructor, and course developer to HP Networking. In addition, Jeff is a network consultant on IPv6 systems interoperability and presents IPv6 lectures and hands-on labs at various technical conferences. His involvement in the computer industry for 32 years has culminated in the concentration of his endeavors in the internetworking portion of the industry for over 25 of those years. His designs are in thousands of networks throughout the world. Jeff has enjoyed successful career advancements with several well-known network equipment manufacturers as a pre-sales consulting engineer and technical instructor. In an end-user position he has designed mission-critical/high-availability networks.