ZyXEL Communications IES-1248-51A, User Manual

Page: 207 / 654

Chapter 25 Spanning Tree Protocol
IES-1248-51V User’s Guide
207
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 identifies the Ethernet port.
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.
Apply Click Apply to save your changes to the IES-1248-51V’s volatile
memory. The IES-1248-51V loses these changes if it is turned off or
loses power, so use the Config Save link on the navigation panel to
save your changes to the non-volatile memory when you are done
configuring.
Cancel Click Cancel to begin configuring this screen afresh.
Table 53 Spanning Tree Protocol (continued)
LABEL DESCRIPTION