Intermec MobileLAN 21 Series, System Manual

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Configuring the Spanning Tree
4-5
4
Spanning Tree Settings Table (continued)
Parameter Explanation
Secondary LAN
Bridge Priority Determines when and if the access point can become the designated
bridge in a secondary LAN. To become a designated bridge, the access
point must have at least one radio configured as a Station node or be
the endpoint of an IP tunnel. The access point that meets either one of
these requirements and has the highest secondary LAN bridge priority
will be the designated bridge.
The secondary LAN bridge priority can be a value from 0 to 7. If you
set the priority to 0, wireless traffic is encapsulated and will use data
link tunneling to the secondary LAN bridge. The secondary LAN
bridge will then forward the data to the primary LAN.
For more information, see “About Secondary LANs and Designated
Bridges” later in this section.
Secondary LAN
Flooding When an access point is the designated bridge in a secondary LAN, this
parameter specifies the types of frames it passes from the primary LAN
to the secondary LAN.
Disabled
No flooding occurs unless the root access point (in the
Global Flooding screen) enables the Multicast or Unicast Outbound to
Secondary LANs parameter.
Enabled
Multicast and unicast flooding occurs unless the root access
point (in the Global Flooding screen) disables multicast or unicast
flooding.
Multicast Multicast flooding occurs unless the root access point (in
the Global Flooding screen) disables multicast flooding.
Unicast
Unicast flooding occurs unless the root access point (in the
Global Flooding screen) disables unicast flooding.
About the Root Access Point
The root access point is always on the primary LAN and initiates the spanning tree. The
root coordinates the network and distributes global system parameters to other access
points. The root is elected from a group of access points that are designated as root
candidates (access points that are powered on, active, and do not have a root priority of
0). The access point with the highest root priority is the root.
The election process also occurs in the event of a root access point failure. Besides the
root, you should have two or three access points with a non-zero root priority. If two
access points have the same root priority, the access point with the highest Ethernet
address becomes the root. You should configure your network with overlapping
coverage so that the network can automatically recover from any single point of failure.