Brocade Mobility 5181 Access Point Product Reference Guide (Supporting software release 4.4.0.0) - Manual (Page 375)

Brocade Mobility 5181 Access Point Product Reference Guide 361
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Mesh networking overview
9
CAUTION
An access point is Base Bridge mode logs out whenever a Client Bridge associates to the Base
Bridge over the LAN connection. This problem is not experienced over the access point’s WAN
connection. If this situation is experienced, log-in to the access point again.
The access point in client bridge mode attempts to establish up to 3 simultaneous wireless
connections. The second and third connections are established in the background while the
system is running. The first connection needs to be established before the system starts bridging
traffic.
The dual-radio model access point affords users better optimization of the mesh networking
feature by allowing the access point to transmit to other access points (in base or client bridge
mode) using one independent radio and transmit with its associated Clients using the second
independent radio. A single-radio access point has its channel utilization and throughput degraded
in a mesh network, as the access point’s single radio must process both mesh network traffic with
other access points and Client traffic with its associated devices.
Client bridge configuration process example
In this example, two access points are described with the following configurations:
• AP #1 base bridge
• AP #2 repeater (both a base and client bridge)
In the case of a mesh enabled radio, the client bridge configuration always takes precedence over
the base bridge configuration. Therefore, when a radio is configured as a repeater (AP #2), the
base bridge configuration takes effect only after the client bridge connection to AP #1 is
established. Thus, AP #2 keeps scanning to find the base bridge, form the uplink and start
beaconing as a base bridge for downstream client bridge connection. This is by design, as there is
no reason to use a partially broken connection with no uplink to a base bridge.
Spanning tree protocol (STP)
The access point 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.
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.
NOTE
Brocade 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.