ZyXEL Communications XGS-4728F User Manual page 137

Table 30 Advanced Application > Spanning Tree Protocol > MRSTP (continued)
LABEL
Bridge Priority
Hello Time
Max Age
Forwarding
Delay
Port
*
Active
Priority
Path Cost
XGS-4728F User's Guide
DESCRIPTION
Bridge priority is used in determining the root switch, root port and
designated port. The switch with the highest priority (lowest numeric
value) becomes the STP root switch. If all switches have the same
priority, the switch with the lowest MAC address will then become the
root switch. Select a value from the drop-down list box.
The lower the numeric value you assign, the higher the priority for this
bridge.
Bridge Priority determines the root bridge, which in turn determines
Hello Time, Max Age and Forwarding Delay.
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.
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.
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)
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.
Select this check box to activate STP on this port.
Configure the priority for each port here.
Priority decides which port should be disabled when more than one port
forms a loop in the Switch. Ports with a higher priority numeric value
are disabled first. The allowed range is between 0 and 255 and the
default value is 128.
Path cost is the cost of transmitting a frame on to a LAN through that
port. It is recommended that you assign this value according to the
speed of the bridge. The slower the media, the higher the cost - see
Table 25 on page 126 for more information.
Chapter 13 Spanning Tree Protocol
137