ZyXEL Communications ES-3124PWR - Manual (Page 106)

Dimension ES-3124PWR Ethernet Switch
10-6 Spanning Tree Protocol
The following table describes the labels in this screen.
Table 10-4 Spanning Tree Protocol: Configuring
LABEL DESCRIPTION
Active Select this check box to activate 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. The
allowed range is 0 to 65535.
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.
Active Select this check box to activate STP on this port.
Priority Configure the priority for each port here.
Priority decides which port should be disabled when more than one port forms a loop in a switch.
Ports with a higher priority numeric value are disabled first. The allowed range is between 0 and
255 and default value is 128.
Path Cost Path cost is the cost of transmitting a frame on to a LAN through that port. It is assigned according
to the speed of the bridge. The slower the media, the higher the cost - see Table 10-1 for more
information.
Apply Click Apply to save your changes back to the switch.
Cancel Click Cancel to begin configuring this screen afresh.