The following table describes the CIST parameters.Table 27 Common Internal Spanning Tree parameter descriptions

Parameter

Description

 

 

CIST RootShows 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), Learning (LRN), Forwarding (FWD), or

 

Disabled (DSB).

 

 

Role

Shows the current role of this port in the Spanning Tree. The port role can be one of

 

the following: Designated (DESG), Root (ROOT), Alternate (ALTN), Backup (BKUP),

 

Master (MAST), or Unknown (UNK).

 

 

Designated BridgeShows information about the bridge connected to each port, if applicable.

 

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

 

 

Designated Port

The port ID of the port on the Designated Bridge to which this port is connected.

 

 

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.

 

 

Type

Type of link connected to the port, and whether the port is an edge port. Link type

 

values are AUTO, P2P, or SHARED.

 

 

Trunk group informationCommand: /info/l2/trunkTrunk group 1, port state:1:STG 1 forwarding2:STG 1 forwarding

When trunk groups are configured, you can view the state of each port in the various trunk groups.

NOTE: If Spanning Tree Protocol on any port in the trunk group is set to forwarding, the remaining ports in the trunk group will also be set to forwarding.

Information Menu 43