Chapter 25 Configuration: Spanning Tree
GS1900 Series User’s Guide
147
Figure 128 Configuration > Spanning Tree > CIST
The following table describes the labels in this screen.
Table 110 Configuration > Spanning Tree > CIST
LABEL DESCRIPTION
CIST Instance
Priority Configure priority of CIST bridge ID.
Priority is part of bridge ID, used for CIST root bridge selection.
Max Hops Enter a maximum number of hops value. The value can be between 1 and 40.
Forward Delay This is the maximum time (in seconds) a switch will wait before changing states. This delay
is required because every switch must receive information about topology changes before it
starts to forward frames. In addition, each port needs time to listen for conflicting
information that would make it return to a blocking state; otherwise, temporary data loops
might result. The allowed range is 4 to 30 seconds.
As a general rule:
Note: 2 * (Forward Delay - 1) >= Max Age >= 2 * (Hello Time + 1)
Max Age This is the maximum time (in seconds) a switch can wait without receiving a BPDU before
attempting to reconfigure. All switch ports (except for designated ports) should receive
BPDUs at regular intervals. Any port that ages out STP information (provided in the last
BPDU) becomes the designated port for the attached LAN. If it is a root port, a new root
port is selected from among the switch ports attached to the network. The allowed range is
6 to 40 seconds.
Tx Hold Count Enter a transmission hold count value. The value can be between 1 and 10.
Hello Time This is the time interval in seconds between BPDU (Bridge Protocol Data Units)
configuration message generations by the root switch. The allowed range is 1 to 10
seconds.
Apply Click Apply to save the changes.
Cancel Click Cancel to discard the changes.
