Web application
PROmesh P20 - User Manual
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Configure the protocol for your application case:
Forward delay: The time that a port waits before it switches from RSTP Learning and Listening
status in den Forwarding status. Enter a value between 4 and 30 seconds.
Maximum age: The time that a bridge waits before trying a new configuration without receiving
messages from the Spanning Tree configuration protocol. Enter a value between 6 and 40 seconds.
Priority: This value is used for the negotiation of the root bridge. The bridge with the lowest value
has highest priority and is selected as root bridge. The value has to lie between 0 and 61440 and
be a multiple of 4096.
Hello time: The time interval in which the switch sends BPDU packages (Bridge Protocol Data Unit)
to check the current status of the RSTP. Enter a value between 1 and 10 seconds.
Max hop: Here you can limit the number of hops. After the specified number has been reached, the
BPDU package is rejected.
Revision & Name: These values are important for MSTP. Switches that use the same values belong
to a single MST region.
Use the rule mentioned below to configure Forward Delay, Maximum Age and Hello Time:
2*(ForwardDelayTime-1) >= MaxAge >= 2*(He1)
Recommended procedure for setting the parameter: First select a value for the
Hello Time
. Subsequently
calculate the lower limit of the Maximum Age with the formula 2 * (Hello Time + 1). Now select a value for
the
Forward Delay Time
. From this, calculate the upper limit for the Maximum Age with the formula
2*(Forward Delay Time – 1). Subsequently, set the Maximum Age to a value that lies between the lower
and upper limits calculated earlier. Keep in mind that the value additionally must lie between 6 and 40
seconds. If this is not the case, use new values for
Hello Time
and
Forward Delay Time
to determine the
Maximum Age with upper and lower limit.
After suitable values have been created, click Apply to save the changes. The Root bridge information is
now displayed in the upper area of the page.
Instance Configuration
In this menu, you can create Multiple Spanning Tree instances. In principle, you could create a separate
spanning tree for each VLAN. The following settings are required for this:
MSTI ID
: Select the “Multiple Spanning Tree Instance ID here. This ID has to identical for all
switches that belong to the same spanning tree.
Bridge Priority
: Each device participating in an MSTI can be assigned a priority. The values can
be assigned in steps of 4096 (starting with 4096). The lower the value, the higher the assigned
priority. The device that has the lowest priority is declared to be the spanning tree master.
