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.