ZyXEL Communications ES-2048, Руководство пользователя

Страница: 108 / 306

Chapter 11 Spanning Tree Protocol
ES-2048 User’s Guide
108
11.5 Rapid Spanning Tree Protocol Status
Click Advanced Application > Spanning Tree Protocol in the navigation panel to display
the status screen as shown next. See Section 11.1 on page 101 for more information on RSTP.
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) the 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) the 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.
Active Select this check box to activate RSTP 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 the default value is 128.
Path Cost Path cost is the cost of transmitting a frame on to a LAN through that port. It is
recommended to assign this value according to the speed of the bridge. The
slower the media, the higher the cost - see Table 23 on page 102 for more
information.
Apply Click Apply to save your changes to the Switch’s run-time memory. The Switch
loses these changes if it is turned off or loses power, so use the Save link on the
top 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 26 Advanced Application > Spanning Tree Protocol > RSTP (continued)
LABEL DESCRIPTION