D-Link xStack User Manual page 156

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Figure 3 - 44 STP Bridge Global Settings window (STP Compatible)
See the table below for descriptions of the STP versions and corresponding setting options.
NOTE: The Hello Time cannot be longer than the Max. Age. Otherwise, a configuration error will
occur. Observe the following formulas when setting the above parameters:
Max. Age <= 2 x (Forward Delay - 1 second)
Max. Age <= 2 x (Hello Time + 1 second)
Configure the following parameters for STP:
Parameter
STP Status
STP Version
Hello Time (1 - 10 Sec)
Max Age (6 - 40 Sec)
®
DGS-3400 Series Layer 2 Gigabit Ethernet Managed Switch
Description
Use the pull-down menu to globally enable or disable STP.
Use the pull-down menu to choose the desired version of STP:
STP – Select this parameter to set the Spanning Tree Protocol (STP) globally on the
switch.
RSTP – Select this parameter to set the Rapid Spanning Tree Protocol (RSTP) globally on
the Switch.
MSTP – Select this parameter to set the Multiple Spanning Tree Protocol (MSTP) globally
on the Switch.
The Hello Time can be set from 1 to 10 seconds. If the inputted Hello Time is more than 2,
the Hello Time is also 2. This is the interval between two transmissions of BPDU packets
sent by the Root Bridge to tell all other switches that it is indeed the Root Bridge. This field
will only appear here when STP or RSTP is selected for the STP Version. For MSTP, the
Hello Time must be set on a port per port basis. See the MST Port Settings section for
further details.
The Max Age may be set to ensure that old information does not endlessly circulate
through redundant paths in the network, preventing the effective propagation of the new
information. Set by the Root Bridge, this value will aid in determining that the Switch has
spanning tree configuration values consistent with other devices on the bridged LAN. If the
value ages out and a BPDU has still not been received from the Root Bridge, the Switch
will start sending its own BPDU to all other switches for permission to become the Root
Bridge. If it turns out that your switch has the lowest Bridge Identifier, it will become the
Root Bridge. The user may choose a time between 6 and 40 seconds. The default value is
20.
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