D-Link xStack User Manual page 157

xStack
Forward Delay (4-30
sec)
Max Hops (1-40)
TX Hold Count (1-10)
Forwarding BPDU
Loopback Detection
LBD Recover Time
NNI BPDU Address
Click Apply to implement changes made.
®
DGS-3400 Series Layer 2 Gigabit Ethernet Managed Switch
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 40. The default is 20. If the Max Hops is less than 6,
the Max Hops is 6.
Used to set the maximum number of Hello packets transmitted per interval. The count can
be specified from 1 to 10. The default is 6.
This field can be Enabled or Disabled. When Enabled, it allows the forwarding of STP
BPDU packets from other network devices. The default is Disabled.
When enabled, the Switch will temporarily block STP switch-wide when a BPDU packet
has looped back. If the Switch detects its own BPDU packet coming back, it signifies a loop
on the network – STP is automatically blocked and an alert is sent to the administrator. The
default is Enabled.
Time allowed (in seconds) for recovery when an STP Loopback is detected. After the timer
has expired the Switch checks for an STP loopback, if no loopback detected, STP is
resumed. Entering 0 will disable LBD recovery.
This field is used to configure the NNI port address.
dot1d – Specifies GVRP's bpdu MAC address of NNI port using the definition of 802.1d.
dot1ad – Specifies GVRP's pdu MAC address of NNI port using the definition of 802.1ad.
146