Spanning Trees
Use the Spanning Trees subtab to view Ether Bridge spanning tree parameters. The Cisco ONS node operates STP according to IEEE 802.1D. The E-Series Ethernet cards support common STPs on a per-circuit basis up to a total of eight STP instances. It does not support per-VLAN STP. In single-card mode, STP can be disabled or enabled on a per-circuit basis during circuit creation. Disabling STP will preserve the number of available STP instances.
 
Item
Description
#
Displays the spanning tree number.
BridgeID
Displays the node unique identifier that transmits the configuration bridge protocol data unit (BPDU); the bridge ID is a combination of the bridge priority and the MAC address.
TopoAge
Displays the amount of time in seconds since the last topology change.
TopoChanges
Displays the number of times the STP topology has been changed since the node booted up.
DesignatedRoot
Displays the designated root for a particular STP instance.
RootCost
Displays the total path cost to the designated root.
RootPort
Displays the port used to reach the root.
MaxAge
Displays the maximum time that received-protocol information is retained before it is discarded.
HelloTime
Displays the time interval, in seconds, between the transmission of configuration BPDUs by a bridge that is the spanning tree root or is attempting to become the spanning tree root.
HoldTime
Displays the minimum time period, in seconds, that elapses during the transmission of configuration information on a given port.
ForwardDelay
Displays the time spent by a port in the listening state and the learning state.
Help
Displays context-sensitive help.

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