D-Link xStack DES-3800 Series User Manual page 107

xStack DES-3800 Series Layer 3 Stackable Fast Ethernet Managed Switch
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
STP Version
Hello Time (1 - 10 Sec) <2>
Max Age (6 - 40 Sec) <20>
Forward Delay (4 - 30 sec) <15 >
Max Hops (1-20) <20>
TX Hold Count (1-10) <3>
Forwarding BPDU <Enabled >
Click Apply to implement changes made.
Description
MST Configuration Identification
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 MST
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 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 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.
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