D-Link DES-3526 - Page 59

xStack DES-3526 / DES-3526DC Layer 2 Stackable Fast Ethernet Managed Switch User Manual
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Figure 6- 23. STP Bridge Global Settings window
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)
The following parameters can be set:
Parameter Description
STP Status
Use the pull-down menu to enable or disable STP globally on the Switch. The default
is Disabled.
STP Version
Use the pull-down menu to choose the desired version of STP to be implemented on
the Switch. There are three choices:
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.
Hello Time
The Hello Time can be set from 1 to 10 seconds. 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.
Max Age
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.
Forward Delay
The Forward Delay can be from 4 to 30 seconds. Any port on the Switch spends this
time in the listening state while moving from the blocking state to the forwarding state.