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Spanning Tree
Configuring STP Status & Global Settings
STEP 2
Cisco Small Business SG200 Series 8-port Smart Switches Administration Guide
•
BPDU Handling—Bridge Protocol Data Units (BPDUs) are the messages
exchanged between switches to calculate STP topology. Select the method
of BPDU packet handling when the spanning tree is disabled on an interface:
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Filtering—Enables the port to discard BPDUs received on interfaces that
are not enabled for STP.
-
Flooding—Allows flooding of BPDUs received on non-spanning-tree
ports to all other non-spanning-tree ports.
Specify the following bridge setting:
•
Priority—The bridge priority value. When switches or bridges are running
STP, each is assigned a priority. After exchanging BPDUs, the switch with the
lowest bridge identifier becomes the root bridge. The bridge priority must
be a multiple of 4096. If you specify a priority that is not a multiple of 4096,
the priority is automatically set to the next lowest multiple of 4096. For
example if you attempt to set the priority to any value between 0 and 4095,
it will be set to 0. The default priority is 32768. The valid range is 0-61440.
The following information appears in the Bridge Settings section of the page:
•
Hello Time—The interval at which a bridge sends configuration messages.
•
Max Age—The amount of time in seconds that a bridge waits before
implementing a topological change.
•
Max Hops—The number of hops before a BDPU is discarded and the port
information is aged out. The maximum hop count is set to 20 and is not
configurable.
•
Forward Delay—The amount of time in seconds that a bridge remains in a
listening and learning state before forwarding packets.
•
Hold Time—The minimum time period, in seconds, that elapses between
the transmission of Configuration BPDUs through a bridge port.
The following information appears in the Designated Root section of the page:
•
Bridge ID—The bridge identifier, which is a concatenation of the bridge
priority and the base MAC address of the bridge.
•
Root Bridge ID—The Bridge ID of the root bridge. The bridge with the lowest
Bridge ID among all the bridges become the root bridge.
•
Root Port—The port number that offers the lowest-cost path from this
bridge to the root bridge. It is significant when the bridge is not the root. The
default is zero.
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