AP-5131 Access Point Product Reference Guide
9-4
The dual-radio model AP-5131 affords users better optimization of the mesh networking feature by
allowing the AP-5131 to transmit to other AP-5131s (in base or client bridge mode) using one
independent radio and transmit with its associated MUs using the second independent radio. A
single-radio AP-5131 has its channel utilization and throughput degraded in a mesh network, as the
AP-5131’s single radio must process both mesh network traffic with other AP-5131s and MU traffic
with its associated devices.
9.1.2 Spanning Tree Protocol (STP)
The AP-5131 performs mesh networking using STP as defined in the 802.1d standard.
Once device association is complete, the client and base bridge exchange Configuration Bridge
Protocol Data Units (BPDUs) to determine the path to the root. STP also determines whether a given
port is a redundant connection or not.
9.1.3 Defining the Mesh Topology
When a user wants to control how the spanning tree determines client bridge connections, they need
to control the mesh configuration. The user must be able to define one node as the root. Assigning a
base bridge the lowest bridge priority defines it as the root.
The AP-5131 can manipulate the path cost assigned to a bridge connection based on that
connection’s RSSI. This results in the spanning tree selecting the optimal path for forwarding data
when redundant paths exist. However, this can be overridden using the preferred list. When using the
preferred list, the user enters a priority for each bridge, resulting in the selection of the forwarding
link.
NOTE The Symbol AP-4131 access point uses a non-standard form of 802.1d
STP, and is therefore not compatible as a base bridge or client bridge
within an AP-5131 managed network.
NOTE Symbol recommends using the Mesh STP Configuration screen to
define a base bridge as a root. Only advanced users should use the
Advanced Client Bridge Settings screen’s Preferred List to define the mesh
topology, as omitting a bridge from the preferred list could break
connections within the mesh network.