ZyXEL 2WG 用户指南

Chapter 7 Bridge Screens

ZyWALL 2WG User’s Guide

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 102   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.

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.

The ZyWALL uses IEEE 802.1w RSTP (Rapid Spanning Tree Protocol) that allow faster 
convergence of the spanning tree (while also being backwards compatible with STP-only 
aware bridges). Using RSTP, topology change information does not have to propagate to the 
root bridge and unwanted learned addresses are flushed from the filtering database. In RSTP, 
the port states are Discarding, Learning, and Forwarding.

To see more information on bridging refer to 

.

To see more advanced information on bridging refer to