Spanning Tree Algorithm
115
Instruction Manual - NXA-ENET8-POE+
Perform these steps to show the VLAN members of an MSTP instance:
1.
Click
Spanning Tree
>
MSTP
.
2.
Select
Configure Global
from the Step list.
3.
Select
Show Member
from the Action list.
Configuring Interface Settings for MSTP
Use the Spanning Tree > MSTP (Configure Interface - Configure) page to configure the STA interface settings for an MST instance.
The following table lists the options on this page:
FIG. 126
Displaying Members of an MST Instance
Spanning Tree - MSTP Options
MST ID
Instance identifier to configure. (Default: 0)
Interface
Displays a list of ports or trunks.
STA Status
Displays the current state of this interface within the Spanning Tree. (See the "
section on page 111 for more information.)
• Discarding - Port receives STA configuration messages, but does not forward packets.
• Learning - Port has transmitted configuration messages for an interval set by the Forward Delay
parameter without receiving contradictory information. Port address table is cleared, and the
port begins learning addresses.
• Forwarding - Port forwards packets, and continues learning addresses.
Priority
Defines the priority used for this port in the Spanning Tree Protocol. If the path cost for all ports
on a switch are the same, the port with the highest priority (i.e., lowest value) will be configured as
an active link in the Spanning Tree. This makes a port with higher priority less likely to be blocked if
the Spanning Tree Protocol is detecting network loops. Where more than one port is assigned the
highest priority, the port with lowest numeric identifier will be enabled. (Default: 128; Range: 0-
240, in steps of 16)
Admin MST Path Cost
This parameter is used by the MSTP to determine the best path between devices. Therefore, lower
values should be assigned to ports attached to faster media, and higher values assigned to ports
with slower media. (Path cost takes precedence over port priority.) Note that when the Path Cost
Method is set to short (page 104), the maximum path cost is 65,535.
By default, the system automatically detects the speed and duplex mode used on each port, and
configures the path cost according to the values shown below. Path cost "0" is used to indicate
auto-configuration mode. When the short path cost method is selected and the default path cost
recommended by the IEEE 8021w standard exceeds 65,535, the default is set to 65,535.
The recommended range is listed in the Recommended STA Path Cost Range table on page 109.
The default path costs are listed in the Default STA Path Costs table on page 110.