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Rockwell Automation Publication 1783-UM006A-EN-P - May 2014
305
Configuring Spanning Tree Protocol
Chapter 9
Creating the Spanning-tree
Topology
In this figure, bridge 4 is elected as the spanning-tree root because the priority of
all the access points is set to the default (32768) and bridge 4 has the lowest
MAC address. However, because of traffic patterns, number of forwarding
interfaces, or link types, bridge 4 might not be the ideal spanning-tree root. By
increasing the priority (lowering the numerical value) of the ideal bridge so that it
becomes the spanning-tree root, you force a spanning-tree recalculation to form a
new topology with the ideal bridge as the spanning-tree root.
Figure 89 - Spanning-tree Topology
Spanning-tree Interface States
Propagation delays can occur when protocol information passes through a
wireless LAN. As a result, topology changes can take place at different times and
at different places in the network. When an interface transitions directly from
nonparticipation in the spanning-tree topology to the forwarding state, it can
create temporary data loops. Interfaces must wait for new topology information
to propagate through the LAN before starting to forward frames. They must
allow the frame lifetime to expire for forwarded frames that have used the old
topology.
Each interface on a access point using spanning tree exists in one of these states:
Table 89 - Spanning Tree States
State
Description
Blocking
The interface does not participate in frame forwarding.
Listening
The first transitional state after the blocking state when the spanning tree determines that
the interface can participate in frame forwarding.
Learning
The interface prepares to participate in frame forwarding.
Forwarding
The interface forwards frames.
Disabled
The interface is not participating in spanning tree because of a shutdown port, no link on
the port, or no spanning-tree instance running on the port.
LAN segment A
LAN segment B
Bridge 1
Bridge 3
Bridge 2
Bridge 4
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Содержание 1783-WAPAK9
Страница 240: ...240 Rockwell Automation Publication 1783 UM006A EN P May 2014 Chapter 6 Administering the WAP Access Notes...
Страница 300: ...300 Rockwell Automation Publication 1783 UM006A EN P May 2014 Chapter 8 Configuring Multiple SSIDs Notes...
Страница 440: ...440 Rockwell Automation Publication 1783 UM006A EN P May 2014 Chapter 14 Configuring RADIUS and TACACS Servers Notes...
Страница 456: ...456 Rockwell Automation Publication 1783 UM006A EN P May 2014 Chapter 15 Configuring VLANs...
Страница 476: ...476 Rockwell Automation Publication 1783 UM006A EN P May 2014 Chapter 16 Configuring QoS Notes...
Страница 482: ...482 Rockwell Automation Publication 1783 UM006A EN P May 2014 Chapter 17 Configuring Filters...
Страница 489: ...Rockwell Automation Publication 1783 UM006A EN P May 2014 489 Configuring Filters Chapter 17...
Страница 520: ...520 Rockwell Automation Publication 1783 UM006A EN P May 2014 Chapter 19 Configuring SNMP Notes...
Страница 572: ...572 Rockwell Automation Publication 1783 UM006A EN P May 2014 Chapter 21 Troubleshooting Notes...
Страница 578: ...578 Rockwell Automation Publication 1783 UM006A EN P May 2014 Appendix A Protocol Filters Notes...
Страница 594: ...594 Rockwell Automation Publication 1783 UM006A EN P May 2014 Appendix C Error and Event Messages Notes...
Страница 600: ...600 Rockwell Automation Publication 1783 UM006A EN P May 2014 Glossary Notes...
Страница 610: ...610 Rockwell Automation Publication 1783 UM006A EN P May 2014 Index Notes...
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