D-Link DES-6500 - Switch User Manual page 59

Max Age
Forward Delay
Max Hops
TX Hold Count
Forwarding BPDU
Loopback Detection
LBD Recover Timer
Click Apply to implement changes made.
xStack DES-6500 Modular Layer 3 Chassis Ethernet Switch User Manual
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 block STP 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 Timer times out. 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.
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)
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