ZyXEL Communications MGS3750-28F User Manual page 32

Chapter 6 Advanced Application Configurations
Table 15 Multiple Spanning Tree Protocol Screen
LABEL DESCRIPTION
Max Age This is the maximum time (in seconds) the 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.
Forwarding Delay This is the maximum time (in seconds) the 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)
Maximum hops Enter the number of hops (between 1 and 255) in an MSTP region before the BPDU is
discarded and the port information is aged.
Configuration Name Enter a descriptive name (up to 32 characters) of an MST region.
Revision Number Enter a number to identify a region's configuration. Devices must have the same
revision number to belong to the same region.
Apply Click Apply to save your changes to the Switch's run-time memory. The Switch loses
these changes if it is turned off or loses power.
Cancel Click Cancel to begin configuring this screen afresh.
Instance Instances can be added or removed from the table. For example, if instance 1 is added
with instance priority 20480 (default is 32768) , then it mirrors VLAN 10 - 20. The port
status for MSTP spanning tree can be configured; configuration is identical to the RSTP
port.
Instance Enter the number you want to use to identify this MST instance on the Switch. The
Switch supports instance numbers 0-15.
Bridge Priority Set the priority of the Switch for the specific spanning tree instance. The lower the
number, the more likely the Switch will be chosen as the root bridge within the
spanning tree instance.
Enter priority values between 0 and 61440 in increments of 4096 (thus valid values
are 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768, 36864, 40960, 45056,
49152, 53248, 57344 and 61440).
VLAN Range Enter the start of the VLAN ID range that you want to add or remove from the VLAN
range edit area in the Start field. Enter the end of the VLAN ID range that you want to
add or remove from the VLAN range edit area in the End field.
Next click:
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•
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Port This field displays the port number.
* Settings in this row apply to all ports.
Use this row only if you want to make some settings the same for all ports. Use this
row first to set the common settings and then make adjustments on a port-by-port
basis.
Note: Changes in this row are copied to all the ports as soon as you make them.
Active Select this check box to add this port to the MST instance.
Add - to add this range of VLAN(s) to be mapped to the MST instance.
Remove - to remove this range of VLAN(s) from being mapped to the MST
instance.
Clear - to remove all VLAN(s) from being mapped to this MST instance.
MGS3750-28F User's Guide
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