Routing IP and IPX A-7Network Organization, Structure andPhysical LayoutSome organizations are structured into departmentsdetermined by the physical layout of their workenvironment, so it is natural to divide the corporatenetwork into separate logical networks. Routingbecomes the obvious candidate for handling theseindividual LANs.The InternetThe protocol adopted by the Defense Data Network(DDN) for the Internet, is based on obtaining andabiding by, a registered Internet address range. Thismakes a router the ideal choice for accessing theInternet. Unfortunately, new applicants are likely toonly get a Class C registered Internet address,preventing more than 254 connections on onebridged IP LAN.Routing IP and IPXRunning a bridged network allows workstations tocommunicate directly between one another. A PCuser wishing to communicate with a remote networkserver is totally unaware of any intervening bridges.This is known as transparent operation.Figure A-3 Example NetworkRc.bk : RCAPPA.FRM Page 7 Thursday, July 10, 1997 9:53 AM
