3Com Access Builder 7000 User Manual

Contents

1-2 CHAPTER 1: BRIDGE/ROUTER MODULETypically, the Bridge/Router module is used to interconnect LANsrunning protocols such as Transmission Control Protocol/InternetProtocol (TCP/IP) or Novell Internetwork Packet Exchange (IPX). Themodule offers full LAN-to-LAN connectivity at speeds up to 64 Kilobitsper second (Kbps) on each ISDN channel (128 Kbps in total) and up to2 Megabits per second (Mbps) on the WAN port.The maximum bandwidth of the Bridge/Router Module is 2 Mbps. If youhave a single leased-line link running at 2 Mbps connected to a WANport, you must disable the ISDN ports and the second WAN port.In the USA, some ISDN services run over 56 Kbps channels. Basic RateISDN therefore offers connectivity of 112 Kbps in total.Benefits of ISDNISDN is an extension of the national and international public switchedtelephone network, which offers a digital end-to-end telecommunicationsystem, providing a better quality service than available using the analogtelephone network. The principal benefits of ISDN are:n Fast call setup times, typically taking less than one second for nationalcalls.n Greater bandwidth with multiple channels.The basic rate service, often referred to as ISDN 2, carries two 64 Kbps(possibly 56 Kbps in USA) user channels, called B channels and one16 Kbps control channel called the D channel. The line service ispresented into the customers premises through a standard RJ45 socket.The PRI Bridge/Router module is designed to operate with Primary RateISDN services provided to the AccessBuilder 7000 through the PRIInterface Module and supports up to eight 64 Kbps (possibly 56 Kbps inUSA) user channels.A significant aspect of the ISDN service is that it can be provided overthe same wiring that was installed for the original telephone service.Therefore, ISDN can be made available relatively cheaply almostanywhere that previously had access to the analog system. The cost of