Communication Module RSTP Diagnostics

Introduction

Use the RSTP Diagnostic page to display either dynamically generated or static data for a BMX NOC 0401 (M340) communication module’s RSTP service.

Use the Refresh Every 500ms checkbox to display static or dynamic data, as follows:

When the checkbox is...	This page...
Selected	Displays data that is dynamically updated every 500 ms, and Increments the number at the top of the table each time data is refreshed
De-selected	Displays static data, and Does not Increment the number at the top of the table, which instead displays a constant value

NOTE: Before you can open the Diagnostic window, connect the DTM for the target communication module to the physical module. To do this, select the module node in the DTM Browser, then select Edit → Connect.

The RSTP Diagnostic page looks like this:

To open this page:

Step	Action
1	In the DTM Browser, select the communication module and click the right mouse button. A pop-up menu opens.
2	In the menu, select Device menu → Diagnostic.
3	In the left pane of the Diagnostic window, select the communication module node.
4	Click on the RSTP Diagnostic tab to open that page.

RSTP Diagnostic Parameters

The RSTP Diagnostic page displays the following parameters for each communication module port:

Parameter	Description
Bridge RSTP Diagnostic:
Bridge ID	An 8-byte bridge identification field is comprised of a 2 sub-fields: Bridge Priority: a 2-byte value from 0 to 65535—with a default of 32768—assigned to the module’s embedded Ethernet switch MAC Address (see below)
MAC Address	The Media Access Control address of a device, found on the front of the module.
Designated Root ID	The Bridge ID of the root switch.
Root Path Cost	The aggregate cost of port costs from this switch back to the root switch.
Default Hello Time	The interval at which Configuration BPDU messages will be transmitted during a network convergence. For RSTP this is a fixed value of 2 seconds.
Learned Hello Time	The current Hello Time value learned from the root switch.
Configured Max Age	The value that other switches use for MaxAge when this switch is acting as the root. Valid range: 6 to 40
Learned Max Age	The maximum age learned from the root switch. This is the actual value currently used by this switch.
Total Topology Changes	The total number of topology changes detected by this switch since the management entity was last reset or initialized.
Ports 3 and 4 RSTP Statistics:
Status	The port's current state as defined by RSTP Protocol. This state controls the action the port takes when it receives a frame. Possible values are: disabled, discarding, learning, forwarding.
Role:	The port’s current role per RSTP protocol. Possible values are: root port, designated port, alternate port, backup port, disabled port.
Cost	The logical cost of this port as a path to the root switch. If this port is configured for AUTO then the cost is determined based on the connection speed of the port.
STP Packets	A value in this field indicates that a device on the network has the STP protocol enabled. NOTE: Other devices, with STP enabled, can severely affect the network convergence times. Schneider Electric recommends the STP protocol (but not the RSTP protocol) be disabled on every network device capable of supporting it. The communication module does not support the STP protocol. The module’s embedded switch ignores ignore STP packets.