Information Commands

In addition to seeing if Common Internal Spanning Tree (CIST) is enabled or disabled, you can view the following CIST bridge information:

•Status of Uplink Fast (upfast)

•CIST root

•CIST regional root

•Priority

•Maximum age value

•Forwarding delay

•Hops

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

•Port number and priority

•Cost

•State

•Role

•Designated bridge and port

•Hello interval

•Link type and port type

The following table describes the CIST parameters.

Table 25 Common Internal Spanning Tree parameter descriptions

Parameter

Description

 

 

CIST Root

Shows information about the root bridge for the Common Internal Spanning Tree

 

(CIST). Values on this row of information refer to the CIST root.

 

 

CIST Regional Root

Shows information about the root bridge for this MSTP region. Values on this row of

 

information refer to the regional root.

 

 

Priority (bridge)

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

 

STP root bridge.

 

 

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.

 

 

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.

 

 

Hops

Shows the maximum number of bridge hops allowed before a packet is dropped.

 

 

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 can be one of the following:

 

Discarding (DISC), Forwarding (FWD), or Disabled (DSB).

 

 

 

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