Spanning Trees

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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.