How Bridges Learn A-5
not be placed on LAN A. Therefore, frames passing between LAN B and LANs C or D will not impact the overall performance of the LAN.
Figure A–2 Multiple Remote Bridge
Multiple Paths With only a single physical path between LANs, the network is Between Bridge LANs susceptible to link and bridge failures. In the event of a failure, the
connection between any of the LANs upstream or downstream from the point of failure will be broken. A more resilient network of interconnected LANs can be established by providing more than one link between any two of the LANs.
Normally, this network would soon encounter serious problems resulting from a loop, around which frames could endlessly travel if precautions aren't taken by the bridges. To prevent loops, you can enable the Spanning Tree Protocol (STP).
When STP is enabled, the bridges send out frames to inquire if there are other bridges on the network. By exchanging information, the bridges block ports that cause the loops and ensure that there is only ever one active path through the network. If one of the links or bridges fail, the
