ZyXEL Communications OLT-1308, User Manual, Page: 114 / 314

Chapter 11 Spanning Tree Protocol
OLT-1308 Series User’s Guide
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11.3 Configure STP
To configure STP, click the Configuration link in the Spanning Tree Protocol screen as
shown next. Refer to Section 11.1 on page 111 for background information.
Figure 42 Spanning Tree Protocol: Configuration
The following table describes the labels in this screen.
Table 32 Spanning Tree Protocol: Configuration
LABEL DESCRIPTION
Status Click Status to display the Spanning Tree Protocol Status screen.
Active Select this check box to activate STP. Clear this checkbox to disable STP.
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: 2 * (Forward Delay - 1) >= Max Age >= 2 * (Hello Time + 1)
Port This field displays the port number.