3Com Switch 4800G 24-Port Configuration Manual page 191

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Setting DLDP Mode
Setting the Interval for
Sending Advertisement
Packets
c
Setting the DelayDown
Timer
To do... Use the command...
Enable DLDP dldp enable
DLDP takes effect only when it is enabled both globally and on a port.
Follow these steps to set DLDP mode:
To do...
Enter system view
Set DLDP mode
You can set the interval for sending Advertisement packets to enable
unidirectional links to be detected in time.
Follow these steps to set the interval for sending Advertisement packets:
To do...
Enter system view
Set the interval for
sending Advertisement
packets
CAUTION:
Set the interval for sending Advertisement packets to a value not longer than
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one-third of the STP convergence time. If the interval is too long, STP loops
may occur before unidirectional links are torn down; if the interval is too short,
network traffic may increase in vain due to excessive Advertisement packets.
To enable DLDP to operate properly, make sure the intervals for sending
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Advertisement packets on both sides of a link are the same.
On some ports, when the Tx line fails, the port goes down and then comes up
again, causing optical signal jitters on the Rx line. When a port goes down due to
a Tx failure, the device transits to the DelayDown state instead of the Inactive state
to prevent the corresponding neighbor entries from being removed. In the same
time, the device triggers the DelayDown timer. If the port goes up before the timer
expires, the device restores the original state; if the port remains down when the
timer expires, the devices transits to the Inactive state.
Follow these steps to set the DelayDown timer
Use the command...
system-view
dldp work-mode { enhance |
normal }
Use the command... Remarks
system-view -
dldp interval time Optional
5 seconds by default
The interval for sending Advertisement
packets applies to all the DLDP-enabled
ports.
DLDP Configuration Task List
Remarks
Required
Disabled on a port by default
You can perform this operation on an
optical port or an electrical port.
Remarks
-
Optional
Normal by default
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