Chapter 6 Bridge Screens; Bridge Loop; Spanning Tree Protocol (Stp); Figure 42 Bridge Loop: Bridge Connected To Wired Lan - ZyXEL Communications 35 Series User Manual

This chapter describes how to configure bridge settings. This chapter is only applicable when
the ZyWALL is in bridge mode.

6.1 Bridge Loop

The ZyWALL can act as a bridge between a switch and a wired LAN or between two routers.
Be careful to avoid bridge loops when you enable bridging in the ZyWALL. Bridge loops
cause broadcast traffic to circle the network endlessly, resulting in possible throughput
degradation and disruption of communications. The following example shows the network
topology that can lead to this problem:
• If your ZyWALL (in bridge mode) is connected to a wired LAN while communicating
with another bridge or a switch that is also connected to the same wired LAN as shown
next.

Figure 42 Bridge Loop: Bridge Connected to Wired LAN

To prevent bridge loops, ensure that your ZyWALL is not set to bridge mode while connected
to two wired segments of the same LAN or you enable RSTP in the Bridge screen.

6.2 Spanning Tree Protocol (STP)

STP detects and breaks network loops and provides backup links between switches, bridges or
routers. It allows a bridge to interact with other STP-compliant bridges in your network to
ensure that only one route exists between any two stations on the network.

Chapter 6 Bridge Screens

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