ZyXEL Communications XGS-4728F, User Manual

Page: 133 / 426

Chapter 13 Spanning Tree Protocol
XGS-4728F User’s Guide
133
The following table describes the labels in this screen.
Table 30 Advanced Application > Spanning Tree Protocol > RSTP
LABEL DESCRIPTION
Status Click Status to display the RSTP Status screen (see Figure 71 on page
134 ).
Active Select this check box to activate RSTP. Clear this checkbox to disable
RSTP.
Note: You must also activate Rapid Spanning Tree in the
Advanced Application > Spanning Tree Protocol >
Configuration screen to enable RSTP on the Switch.
Bridge Priority 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.
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.
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.
Forwarding
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)
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.