Information Commands

You can also refer to the following port-specific RSTP information:

•Port number and priority

•Cost

•State

•Role

•Designated bridge and port

•Link type

The following table describes the STP parameters in RSTP or MSTP mode.

Table 24 Rapid Spanning Tree parameter descriptions

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. A setting of

 

zero (0) indicates that the cost will be set to the appropriate default after the link speed

 

has been auto-negotiated.

 

 

State

Shows the current state of the port. The State field in RSTP/MSTP mode can be one of

 

the following: Discarding (DISC), Learning (LRN), Forwarding (FWD), or Disabled

 

(DSB).

 

 

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