The switch software uses the IEEE 802.1d Spanning Tree Protocol (STP). If RSTP/MSTP is turned on, see the “Rapid Spanning Tree information” section for Spanning Tree Group information. In addition to seeing if STP is enabled or disabled, you can view the following STP bridge information:

Status of Uplink Fast (upfast)Current root MAC addressPath-CostPortHello intervalMaximum age valueForwarding delayAging timeYou can also refer to the following port-specific STP information:

Port number and priority

Cost

State

Port Fast Forwarding stateDesignated bridgeDesignated portThe following table describes the STP parameters.Table 22 STP parameters

Parameter

Description

 

 

 

Current Root

Shows information about the root bridge for the Spanning Tree. Information includes the

 

priority (hex) and MAC address of the root.

 

 

 

Path-Cost

Path-cost is the total path cost to the root bridge. It is the summation of the path cost

 

between bridges (up to the root bridge).

 

 

 

Port

The current root port refers to the port on the switch that receives data from the current

 

root. Zero (0) indicates the root bridge of the STP.

 

 

 

Priority (bridge)

The bridge priority parameter controls which bridge on the network will become the STP

 

root bridge.

 

 

 

Hello

The hello time parameter specifies, in seconds, how often the root bridge transmits a

 

configuration bridge protocol data unit (BPDU). Any bridge that is not the root bridge

 

uses the root bridge hello value.

 

 

 

MaxAge

The maximum age parameter specifies, in seconds, the maximum time the bridge waits

 

without receiving a configuration bridge protocol data unit before it reconfigures the STP

 

network. If the bridge is not the root bridge, it uses the MaxAge value of the root bridge.

 

 

 

FwdDel

The forward delay parameter specifies, in seconds, the amount of time that a bridge port

 

has to wait before it changes from learning state to forwarding state. If the bridge is not

 

the root bridge, it uses the FwdDel value of the root bridge.

 

 

 

Aging

The aging time parameter specifies, in seconds, the amount of time the bridge waits

 

without receiving a packet from a station before removing the station from the Forwarding

 

Database.

 

 

 

Priority (port)

The port priority parameter helps determine which bridge port becomes the designated

 

port. In a network topology that has multiple bridge ports connected to a single segment,

 

the port with the lowest port priority becomes the designated port for the segment.

 

 

 

Cost

The port path cost parameter is used to help determine the designated port for a segment.

 

Generally speaking, the faster the port, the lower the path cost.

 

 

 

State

The State field shows the current state of the port. The State field can be one of the

 

following: BLOCKING, LISTENING, LEARNING, FORWARDING, or DISABLED.

 

 

 

Designated bridge

Shows information about the bridge connected to each port, if applicable. Information

 

includes the priority (hex) and MAC address of the Designated Bridge.

 

 

 

 

Information Menu 38