Radio Configuration / Diagnostic Utility
RLXIB-IHW-66
♦
802.11a, b, g
User Manual
Industrial Hotspot
ProSoft Technology, Inc.
Page 47 of 109
May 18, 2009
4.2.3 Rapid
Spanning Tree Functionality
The software’s built-in Rapid Spanning Tree (RSTP) functionality enables you to
set up full redundancy between radios or other devices. Spanning Tree shuts off
ports as necessary to prevent loops. If loops are created in an Ethernet network,
packets can be circulated endlessly, consuming all the bandwidth and making
the network unusable.
RSTP allows users to create truly redundant connections between any two points
in the network. The radios detect the redundant paths and keep one connection
alive for communications. If the primary connection fails for any reason, the
secondary connection is quickly transitioned to a state to forward packets,
allowing the network to adapt itself to handle problems without customer
intervention.
RSTP uses active communications between network devices to propagate
changes in the network and to cause transitions to occur much more quickly.
Because RSTP is an IEEE standard, IH radios work in conjunction with wired
Ethernet switches to form a redundant network.
Each RSTP device (RLXIB Radio or Ethernet switch) communicates with other
RSTP devices in the network via packets called Bridge Protocol Data Units
(BPDUs). BPDUs are sent out each of the devices ports. In a wired switch this
would be from each of the Ethernet ports. In an RLXIB Radio, in addition to the
Ethernet port, each wireless link is considered a port. These BPDUs are the
communications means to allow each RSTP device in the network to make sure
that the proper connections still exist.
In the following illustration, this RLXIB Radio has 4 RSTP "ports":
Ethernet port (1)
A port for its parent connection (2)
A port for each of its two child connections (11 and 12).