# Displaying MSTP general information

Use this procedure to view MSTP information.

## Procedure steps

1. From the navigation tree, double-click VLAN.

2. From the VLAN tree, double-click Spanning Tree.

3. From the Spanning Tree folder, click MSTP.

4. Select the Globals tab.

## Variable definitions

The following table outlines the parameters of the Globals tab.

Table 1. MSTP Globals tab parameters
Variable | Value
--- | ---
PathCostDefaultType | Specifies the version of the Spanning Tree default Path Costs that are used by this Bridge. A 16-bit value uses the 16-bit default path costs from IEEE Standard 802.1D-1998. A 32-bit value uses the 32-bit default path costs from IEEE Standard. 802.1t.
TxHoldCount | Specifies the value used by the Port Transmit state machine to limit the maximum transmission rate.
MaxHopCount | Specifies the Maximum Hop Count value in 1/100 seconds. The value must be a multiple of 100. The range is 100 to 4000.
NoOfInstancesSupported | Indicates the maximum number of spanning tree instances supported.
MstpUpCount | Specifies the number of times the MSTP Module is enabled. A trap is generated on the occurrence of this event.
MstpDownCount | Specifies the number of times the MSTP Module is disabled. A trap is generated on the occurrence of this event.
ForceProtocolVersion | Signifies the version of the Spanning Tree Protocol that the bridge is currently running. stpCompatible indicates that the bridge is using the Spanning Tree Protocol as specified in IEEE 802.1D. rstp indicates that the bridge is using the Rapid Spanning Tree Protocol as specified in IEEE 802.1w. mstp indicates that the bridge is running the Multiple Spanning Tree Protocol as specified in IEEE 802.1s.
BrgAddress | The bridge address is generated when events like protocol up or protocol down occurs.
Root | The bridge identifier of the root of the common spanning tree as determined by the Spanning Tree Protocol as executed by this node. This value is used as the CIST Root Identifier parameter in all Configuration BPDUs originated by this node.
RegionalRoot | The bridge identifier of the root of the Multiple Spanning Tree region as determined by the Spanning Tree Protocol as executed by this node. This value is used as the CIST Regional Root Identifier parameter in all Configuration Bridge PDUs originated by this node.
RootCost | Specifies the cost of the path to the CIST Root as seen from this bridge.
RegionalRootCost | Specifies the cost of the path to the CIST Regional Root as seen from this bridge.
RootPort | Indicates the port number of the port which offers the lowest path cost from the bridge to the CIST Root Bridge
BridgePriority | Indicates the value of the writable portion of the Bridge Identifier comprising the first two octets. The values that are set for Bridge Priority must be in steps of 4096.
BridgeMaxAge | Specifies the value in hundredths of a second that all bridges use for MaxAge when this bridge acts as the root. The value must be a multiple of 100. The range is 600 to 4000.
BridgeForwardDelay | Specifies the value in hundredths of a second that all bridges use for ForwardDelay when this bridge acts as the root. IEEE 802.1D specifies that the range for this parameter is related to the value of BridgeMaxAge. The value must be a multiple of 100. The range is 400 to 3000.
HoldTime | Determines the time interval during which no more than two Configuration BPDUs can be transmitted by this node. This value is measured in units of hundredths of a second.
MaxAge | Specifies the maximum age, in hundredths of a second, of the Spanning Tree Protocol information learned from the network on any port before being discarded. This value is the actual value that this bridge is currently using.
ForwardDelay | Controls how fast a port changes its STP state when moving towards the Forwarding state. This value determines how long the port stays in a particular state before moving to the next state. This value is measured in units of hundredths of a second.
TimeSinceTopology Change | Specifes the time, in hundredths of a second, since the TcWhile Timer for any port in this Bridge was non-zero for the Common Spanning Tree context.
NewRootBridgeCount | Specifies the number of times this Bridge detects a Root Bridge change for the Common Spanning Tree context. A Trap is generated when this event occurs.
TopChanges | Specifies the number of times that at least one non-zero TcWhile Timer occurred on this Bridge for the Common Spanning Tree context.
RegionName | Specifies the region name of the configuration. By default, the Region Name is equal to the Bridge Mac Address.
ConfigIdSel | Specifies the Configuration Identifier Format Selector used by the Bridge. This has a fixed value of 0 which indicates RegionName, RegionVersion, as specified in the standard.
RegionVersion | Denotes the version of the MST Region.
ConfigDigest | Signifies the Configuration Digest value for this Region. This is an MD5 digest value and hence must always be 16 octets long.
RegionConfigChange Count | Specifies the number of times a Region Configuration Identifier Change is detected. A trap is generated when this event occurs.