3Com AccessBuilder 500 User Manual - Optimum Use Of Resource

Bridging and Routing Concepts

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Optimum Use of Resource

Bridged networks use Spanning Tree Protocol (STP) to provide 

network resilience, by retaining redundant links on stand-by, in case 

the primary link fails. This means that you are not making maximum 

use of available resources. 

Routing protocols make each node aware of the primary and alternate 

routes available, ensuring that resources are not wasted.

Routers have been designed to provide the optimum route through 

the network from the workstation through to the destination resource 

with which the user wishes to communicate. In a very large network 

there could be multiple paths available, and these could change as 

dedicated links go in or out of service. These changes in network 

topology are handled by routing protocols. However, when using the 

ISDN the source network can dial direct to the destination network, 

and establish a point-to-point bridged or routed connection. Generally, 

when using this type of ISDN dial-up link, routing does not provide 

much extra benefit.

Network Organization, Structure and Physical Layout

Some organizations are structured into departments determined by the 

physical layout of their work environment, so it is natural to divide the 

corporate network into separate logical networks. Routing becomes 

the obvious candidate for handling these individual LANs.

The Internet

The protocol adopted by the Defense Data Network (DDN) for the 

Internet, is based on obtaining and abiding by, a registered Internet 

address range. This makes a router the ideal choice for accessing the 

Internet. Unfortunately, new applicants are likely to only get a 

Class C

registered Internet address, preventing more than 254 connections on 

one bridged IP LAN.