Information Commands
42
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).
