Network Topology
If your network topology is star shaped, a combination of ISDN and bridging is usually the most efficient and successful option. Routing is a better solution if your network topology is a complex mix of both leased line and ISDN circuits, running at 64 Kbps to 2 Mbps.
Broadcast Storms
Bridges are programmed to automatically forward data packets by default while routers filter data packets by default. These attributes have an impact on the overall flow of data across the network. Much has been made of broadcast storms in connection with bridged networks, where the broadcast signals from bridges propagate to fill all of the wide area bandwidth, and bring the network down. Broadcast storms cannot be attributed to installation of bridges or routers, but by poor protocol implementation and network design. However the deployment of routers can effectively firewall one logical network from another.
Optimum Use of Resource
Bridged networks use Spanning Tree Protocol (STP) to provide network resilience, by retaining redundant links on
Routing protocols make each node aware of the primary and alternate routes available, ensuring that resources (particularly WAN links) 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
