Allied Telesis AT-WA7500 - Manual (Page 108)

5 - Configuring the Spanning Tree
108
About the Access Point Spanning Tree
The AT-WA7500 access point with the same LAN ID arrange themselves
into a self-organized network using a spanning tree topology. The
spanning tree provides efficient, loop-free forwarding of frames through
the network and allows efficient roaming of wireless end devices. It
contains at least a primary LAN and a root access point, but it may also
contain secondary LANs, designated bridges, and other access points.
This spanning tree contains a root access point on the primary LAN and a
designated bridge on the secondary LAN.
Within the spanning tree, access points use Inter Access Point Protocol
(IAPP) or secure IAPP to communicate with each other across the
Ethernet network, over wireless secondary LANs, and through IP tunnels
to remote IP subnets. IAPP also enables fast roaming in an 802.11b or
802.11a network using 802.1x security. Secure IAPP prevents
unauthorized access points from joining the spanning tree.
For example, when an end device roams to a new access point, the new
access point informs the old access points via the root access point that
any traffic for the end device needs to be routed to the new access point.
As end devices are added to or removed from the network, access points
are automatically updated so they can maintain reliable operation and
communication.
Primary LAN
Secondary LAN
Host
Designated
bridge
Root