Advanced Reference Guide
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13
Fast SwitcHub-8mi SNMP
Parameter
Default
Description
Switch
Spanning Tree Algorithm
Enabled
Enable this parameter to participate in an STA compliant network.
Priority
32,768
Device priority is used in selecting the root device, root port, and
designated port. The device with the highest priority becomes the
STA root device. However, if all devices have the same priority,
the device with the lowest MAC address will then become the root
device.
Enter a value from 0 - 65535.
Remember that the lower the numeric value, the higher the priority.
Hello Time
2
The time interval (in seconds) at which the root device transmits a
configuration message.
The minimum value is 1.
The maximum value is the lower of 10 or [(Max. Message Age /
2) -1].
Maximum Message Age 20
The maximum time (in seconds) a device can wait without
receiving a configuration message before attempting to reconfigure.
All device ports (except for designated ports) should receive
configuration messages at regular intervals. Any port that ages out
STA information (provided in the last configuration message)
becomes the designated port for the attached LAN. If it is a root
port, a new root port is selected from among the device ports
attached to the network.
The minimum value is the higher of 6 or [2 x (Hello Time + 1)].
The maximum value is the lower of 40 or [2 x (Forward Delay -
1)].
Forward Delay
15
The maximum time (in seconds) the root device will wait before
changing states (i.e., listening to learning to forwarding). This
delay is required because every device 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 minimum value is the higher of 4 or [(Max. Message Age / 2)
+ 1].
The maximum value is 30.
Port
Priority
128
Defines the priority for the use of a port in the STA algorithm. 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. Where more than one port is assigned
the highest priority, the port with lowest numeric identifier will be
enabled.
The range is 0 - 255.
Parameter
Default
Description
(continued)
Path Cost
10 or 100 This parameter is used by the STA algorithm 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. The default is automatically
set (depending on the negotiated transmission speed) according to
the following formula:
Recommended Path Cost = 1000/(LAN speed in Mbps);
i.e., default is set at 10 for Fast Ethernet or 100 for standard
Ethernet.
The range is 0 - 65535.
Note: Path cost takes precedence over port priority.
Note:
For a listing of the current STA settings, refer to the Spanning Tree Information screen under the
Information & Statistics menu.
Configuring the Out-of-Band Console
You can access the on-board configuration program by attaching a VT100 compatible
device to the switch's serial port. (For more information on connecting to this port, refer
to the section on Making the Connections Required for System Configuration on page 2.)
The communication parameters for this port are accessed from the Console Configuration
screen seen below and described in the following table.
Console Configuration
Console Baudrate 9600
Console Time-Out (in Minutes) 5
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Parameter
Default
Description
Console Baud Rate
9600 bps
The rate at which data is sent between devices. Supported baud
rates are 9600, 19200 bps and autobaud.
Console Time-Out
5 minutes If no input is received from the attached device after this interval
(in minutes), the current session is automatically closed.
Range: 0 - 60 minutes; where 0 indicates disabled.
