D-Link xStack DGS-3600 Series User Manual - page 139
xStack DGS-3600 Series Layer 3 Gigabit Ethernet Managed Switch
Figure 7- 38. STP Bridge Global Settings – STP Compatible 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
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
.
Hello Time (1-10 Sec)
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.
Max Age (6-40 Sec)
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 (4-30
Sec)
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.
Max Hops (1-20)
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
.
TX Hold Count (1-10)
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
.
Forwarding BPDU
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.
Loopback Detection
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
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