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Note: The bridge priority value must be in multiples of 4096. A device with a lower number
has a higher bridge priority. Ex: 4096 is higher than 32768.
Note: The Web GUI allows user select the priority number directly. This is the convinent of
the GUI design. When you configure the value through the CLI or SNMP, you may need to
type the value directly. Please follow the n x 4096 ruls for the Bridge Priority.
Max Age (6-40)
: Enter a value from 6 to 40 seconds here. This value represents the time
that a bridge will wait without receiving Spanning Tree Protocol configuration messages
before attempting to reconfigure.
If the managed Switch is not the root bridge, and if it has not received a hello message
from the root bridge in an amount of time equal to Max Age, then the Managed Switch will
reconfigure itself as a root bridge. Once two or more devices on the network are
recognized as a root bridge, the devices will renegotiate to set up a new spanning tree
topology.
The MAX Age value affects the maximum volume of the RSTP loop. In the RSTP BPDU
packet, there is one field, message age which start from 0, add 1 after passed one hop in
the RSTP loop. When the message age is larger than MAX Age, the BPDU would be
ignored and the lower switches are separated to different RSTP domain. The switches in
other RSTP domain can’t be managed through upper switch.
Since different RSTP aware switches may have their own mechanism to calculate the
message age. So that this is most possibly occurred when interoperate different vendors’
RSTP aware switches together. The maximum volume of the RSTP domain is 23, configure
the MAX Age lower than 23 is recommended.
Hello Time (1-10)
: Enter a value from 1 to 10 seconds here. This is a periodic timer that
drives the switch to send out BPDU (Bridge Protocol Data Unit) packet to check current
STP status.
The root bridge of the spanning tree topology periodically sends out a “hello” message to
other devices on the network to check if the topology is “healthy”. The “hello time” is the
amount of time the root has waited during sending hello messages.
Forward Delay Time (4-30)
: Enter a value between 4 and 30 seconds. This value is the
time that a port waits before changing from Spanning Tree Protocol learning and listening
states to forwarding state.
This is the amount of time of the Managed Switch will wait before checking to see if it
should be changed to a different state.
Once you have completed your configuration, click on
Apply
to apply your settings.
Note
: You must observe the following rule to configure Hello Time, Forwarding Delay, and
Max Age parameter
2 × (Forward Delay Time – 1 sec) ≥ Max Age Time ≥ 2 × (Hello Time value + 1 sec)
4.4.2
STP Port Configuration
This page allows you to configure the port parameter after enabled STP or RSTP.
Port Configuration
Select the port you want to configure and you will be able to view current settings and
status of the port.
Path Cost
: Enter a number between 1 and 200,000,000. This value represents the “cost”
of the path to the other bridge from the transmitting bridge at the specified port.
Priority
: Enter a value between 0 and 240, using multiples of 16. This is the value that
decides which port should be blocked by priority in a LAN.
