

Jamestown, North Carolina
David G. Billings
Technical Instructor & Cisco Academy Instructor
AAS, BSC, MBA, MSIT
MCP, MCP+I, MCSE, MCT, CCNA, CCNP, CCAI
This collection of study
guides, papers, movies, videos, presentations, tables, calculators, posters, questions &
answers, etc. are meant to be used by those preparing to write the Cisco CCNA exam, as
well as IT professionals looking to learn more about networking concepts, and Cisco
routing and switching.
There is no substitution for knowledge and understanding. Cisco has protected the value of
it's certifications by requiring that you KNOW and UNDERSTAND
networking. Memorizing answers to questions will not give you the skills for you to get a
job or keep a job.
About sources
This is a collection from various text, internet sites, and my
own writings I have collected over the years. A lot of the material in these Study Guides
is a collection of the work of others. They are by no means all mine. It is not my
intention to duplicate for my gain the work of others without giving them credit. The
problem is I have not kept, nor could I possibly find, the true sources for a lot of this
information. I have put this series of web pages together only as a consolidator of
information. The only goal is to assist the reader in better understanding networking,
routing, and switching, and to possibly obtain a certification from Cisco as a CCNA. This
collection is not published for my (or any) profit or gain.
Thank you for your understanding.