Spanning Trees


Use the Spanning Trees subtab to view Ether Bridge spanning tree parameters. The Cisco ONS node operates Spanning Tree Protocol (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.

BridgeID

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

Amount of time in seconds since the last topology change.

TopoChanges

Number of times the STP topology has been changed since the node booted up.

DesignatedRoot

Identifies the designated root for a particular STP instance.

RootCost

Identifies the total path cost to the designated root.

RootPort

The port used to reach the root.

MaxAge

Maximum time that received-protocol information is retained before it is discarded.

HelloTime

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

Minimum time period, in seconds, that elapses during the transmission of configuration information on a given port.

ForwardDelay

Time spent by a port in the listening state and the learning state.

Help

Displays context-sensitive help.