Spanning Trees
(ONS 15454 SDH only) 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
#
Spanning tree number.
Bridge ID
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.
Topo Age
Amount of time in seconds since the last topology change.
Topo Changes
Number of times the STP topology has been changed since the node booted up.
Designated Root
Identifies the designated root for a particular STP instance.
Root Cost
Identifies the total path cost to the designated root.
Root Port
Displays the port used to reach the root.
Max Age (sec)
Maximum time that received-protocol information is retained before it is discarded.
Hello Time (sec)
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.
Hold Time (sec)
Minimum time period, in seconds, that elapses during the transmission of configuration information on a given port.
Forward Delay (sec)
Time spent by a port in the listening state and the learning state.
Help
Displays context-sensitive help.

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