A BRIDGING AND ROUTING

Introduction

During the initial configuration of the OfficeConnect Remote you must decide whether to configure the unit as a bridge or as a router although we may help you with this choice with our Quick Configuration options. If you are unsure which option you should choose, read this appendix to help you decide.

Bridges and routers are used to connect networks together. The cost of connecting networks together is generally proportional to the distance over which the network extends and the amount of bandwidth required. Large amounts of bandwidth can be provided easily within a LAN by connecting different segments together with a local bridge. However, it becomes impractical and expensive to extend this bandwidth over larger distances, and it is, therefore, usual to interconnect local high speed networks using bridges or routers connecting over slower speed terrestrial and satellite links.

In the following sections we describe the concepts behind bridging and routing, and discuss the different ways in which LANs can be configured and operated to optimize performance and minimize disruption of traffic on each individual LAN.

Bridging and Routing Concepts

A bridge connects one or more LANs together. It examines each data frame received at a LAN port and forwards any frames that it assumes are for a destination device not connected to that LAN port. The bridge is able to do this by learning which devices are connected to each LAN port.

A router learns much more about the networks connected to it and is able to be much more selective about the data it passes on to other networks and to which networks it transmits. By default routers reject or filter data unless it matches predefined attributes (for example specific protocols or destination network addresses). In large interconnected networks a router selects the best route for data to travel.

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3Com 520, 510, 530 manual Bridging and Routing Concepts