D-Link DES-6500 Manual page 58

Parameter
STP Status
STP Version
Hello Time: (1 - 10 sec)
Max Age: (6 - 40 sec)
Forward Delay: (4 - 30
sec)
Max Hops (1-20)
TX Hold Count (1-10)
Forwarding BPDU
Click Apply to implement changes made.
DES-6500 Chassis-based Layer 3 Ethernet Switch Manual
Description
Use the pull-down menu to enable or disable STP globally on the Switch. The
default is Disabled.
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.
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 STP 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.
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 for-
warding 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 BDPU 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.
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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