User guide

Radio Configuration / Diagnostic Utility RLX-IH ♦ 802.11b
Industrial Hotspot
ProSoft Technology, Inc. Page 37 of 99
April 10, 2007
Each IH radio contains a switch table, which tells it how to forward Ethernet
packets to get them to their proper destination. When the network topology
changes, the IH radio flushes its Ethernet switch table immediately. This allows it
to pass traffic immediately over the new network topology and learn the
configuration in the process. Until the learning is complete, the packets are
broadcast to their destination. As each packet is seen and the switch table
rebuilds, the radios return to directing packets to their destinations.
4.2.2 Spanning Tree Settings
This configuration page opens when you click the Spanning Tree button on the
Radio Configuration form.
Field Description
Enable Spanning Tree
Spanning Tree is enabled when this box is checked. Without
spanning tree, redundant connections might exist if multiple radio
links are created in parallel with each other. Redundant connections
are blocked only if spanning tree is enabled. Additionally, spanning
tree is used to flush the Ethernet switch table when the network
topology changes as described in the section on Automatic Parent
Selection. Firmware versions 2.5xx and above also support Rapid
Spanning Tree (RSTP), and will default to this mode when enabled.
The recommended setting for spanning tree is "Enabled".
Ethernet Edge Port
Because RSTP is an active protocol, it depends on communication
between RSTP devices. If no RSTP device is connected to the
radio's Ethernet port, the handshake cannot take place. In this case
RSTP reverts to STP. This means that the Ethernet port will be forced
to adhere to the timer based transition protocol of STP.
Therefore on network transitions and power up, communications will
not be allowed over the Ethernet port for 30 to 45 seconds. This
setting is an indication that no redundant connections exist out this
port and communication can immediately be allowed. If for some
reason a BPDU is received on this port, the RSTP protocol will
negotiate properly and handle any possible redundant paths.
The recommended setting for Ethernet Edge Port is "Enabled".