Alaxala AX2200S Series Configuration Manual page 330

19 Spanning Tree Protocol
configuration has the following advantages:

Problems that occur on an edge switch do not result in topology changes for other
edge switches.

Load balancing can be performed among core switches.
Single Spanning Tree is connected by access ports. The figure below shows a
configuration example. In this example, Single Spanning Tree is run on the edge switches,
and PVST+ is run on the core switches. The core switches treat ports connected to edge
switches as access ports. A single VLAN is set up for each edge switch.
Figure 19-7 Connecting to Single Spanning Tree
(2) When PVST+ and Single Spanning Tree coexist on access ports
When PVST+ and Single Spanning Tree coexist, Single Spanning Tree is stopped
(switched to Disable status) on the access port.
(3) Configuration-inconsistency detection functionality
For ports connected on the same VLAN, if an access port, protocol port, or MAC port is set
for the Switch (using an untagged frame), and a trunk port is set for the partner switch
(using a tagged frame), communication for this port will not be possible for the
corresponding VLAN. Ports like these are detected as configuration mismatches. This
mismatch is detected if the Switch has an access port, and the trunk port is set on the
partner switch (using a tagged frame). In this case, the corresponding port is stopped
(Disable status). If the trunk port setting (using a tagged frame) is deleted on the partner
switch, the stopped status is automatically removed after hello-time x 3 seconds (six
seconds by default).
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