User Manual

Psion Teklogix 9160 Wireless Gateway User Manual 189
Chapter 20: Wireless Distribution System
Backup Links and Unwanted Loops In WDS Bridges
Figure 20.2 Extended Network Beyond The Wired Coverage Area
20.1.3 Backup Links and Unwanted Loops In WDS Bridges
Another use for WDS bridging, the creation of backup links, is not supported in this
release of the 9160 Wireless Gateway. The topic is included here to emphasize that
you should not try to use WDS in this way; backup links will result in unwanted,
endless loops of data traffic
If an access point provides Spanning Tree Protocol (STP), WDS can be used to
configure backup paths between access points across the network. For example,
between two access points you could have both a primary path via Ethernet and a
secondary (backup) wireless path via a WDS link. If the Ethernet connection goes
down, STP would reconfigure its map of the network and effectively fix the down
network segment by activating the backup wireless path.
The 9160 Wireless Gateway does not provide STP for this release. Without STP, it is
possible that both connections (paths) may be active at the same time, and result in
an endless loop of traffic on the LAN.
Therefore, be sure not create loops with either WDS bridges or combinations of
Wired (Ethernet) connections and WDS bridges.
For more information, see the “Do not create loops” note under “Configuring WDS
Settings” on page 190.
WDS Bridge
Client Station
Client Station
Client Station
“East Wing” AP
“Poolside” AP
Client Station
LAN
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