Netgear WGX102 참조 매뉴얼

Network, Routing, Firewall, and Basics

B-1

This chapter provides an overview of IP networks, routing, and networking.

As you read this document, you may be directed to various Request For Comment (RFC) 
documents for further information. An RFC is a document published by the Internet Engineering 
Task Force (IETF), an open organization that defines the architecture and operation of the Internet. 
The RFC documents outline and define the standard protocols and procedures for the Internet. The 
documents are listed on the World Wide Web at 

 and are mirrored and indexed 

at many other sites worldwide.

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 expense, Internet access is usually provided by a slower-speed 
wide-area network (WAN) link such as a cable or DSL modem. In order to make the best use of the 
slower WAN link, a mechanism must be in place for selecting and transmitting only the data traffic 
meant for the Internet. The function of selecting and forwarding this data is performed by a router.

A router is a device that forwards traffic between networks based on network layer information in 
the data and on routing tables maintained by the router. In these routing tables, a router builds up a 
logical picture of the overall network by gathering and exchanging information with other routers 
in the network. Using this information, the router chooses the best path for forwarding network 
traffic.