D-Link xStack DGS-3600 User Manual page 116

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
STP Status
Hello Time
Max Age
Forward Delay
Max Hops
TX Hold Count
Forwarding BPDU
Loopback Detection
LBD Recover Time
NOTE: The Loopback Detection function can only be implemented on the Switch if it is configured
both on the STP Global Settings window, and on the STP Port Settings window. Enabling this feature
through only one of these windows will not fully enable the Loopback Detection function.
Click Apply to implement changes made.
xStack DGS-3600 Series Layer 3 Gigabit Ethernet Managed Switch
Description
Use the pull-down menu to enable or disable STP globally on the Switch. The default is
Disabled.
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.
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.
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.
Used to set the number of hops between devices in a spanning tree region before the BPDU
(bridge protocol data unit) packet sent by the Switch will be discarded. Each switch on the
hop count will reduce the hop count by one until the value reaches zero. The Switch will then
discard the BPDU packet and the information held for the port will age out. The user may set
a hop count from 1 to 20. The default is 20.
Used to set the maximum number of Hello packets transmitted per interval. The count can
be specified from 1 to 10. The default is 3.
This field can be Enabled or Disabled. When Enabled, it allows the forwarding of STP BPDU
packets from other network devices. The default is Enabled.
This feature is used to temporarily shutdown a port on the Switch when a BPDU packet has
been looped back to the switch. When the Switch detects its own BPDU packet coming
back, it signifies a loop on the network. STP will automatically be blocked and an alert will be
sent to the administrator. The LBD STP port will restart (change to discarding state) when
the LBD Recover Time times out. The Loopback Detection function will only be
implemented on one port at a time. The user may enable or disable this function using the
pull-down menu. The default is Enabled.
This field will set the time the STP port will wait before recovering the STP state set. 0 will
denote that the LBD will never time out or restart until the administrator personally changes
it. The user may also set a time between 60 and 1000000 seconds. The default is 60
seconds.
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