Network and Routing Basics B-1
This chapter provides an overview of IP networks, routing, and wireless networking.
Related Publications
As you read this document, you may be directed to various RFC documents for further
information. An RFC is a Request For Comment (RFC) published by the Internet Engineering
Task Force (IETF), an open organization that defines th e archit ecture and operation of the Inte rnet.
The RFC documents outline and define the standard protocols and procedures for the Internet. The
documents are listed on the World Wide Web at www.ietf.org and are mirrored and indexed at
many other sites worldwide.
Basic Router Concepts
Large amounts of bandwidth can be provided easily and relatively inexpensively in a local area
network (LAN). However, providing high bandwidth between a local network and the Internet can
be very expensive. Because of this expen se , Internet access is usually provided by a sl ower-speed
wide-area network (WAN) link such as a cable or DSL modem. In order to mak e the bes t use of the
slower WAN link, a mechanism must be in place for sel ecting and transmit ting only t he data t raf fic
meant for the Internet. The function of selecting and forwarding this data is performed by a router.