QTech QSW-2800 series Configuration Manual - 7.4 Uldp Troubleshooting
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down!
%Oct 29 11:09:50 2007 Unidirectional port Ethernet1/1 shut down!
%Oct 29 11:09:50 2007 A unidirectional link is detected! Port Ethernet1/2 need to be shutted
down!
%Oct 29 11:09:50 2007 Unidirectional port Ethernet1/2 shutted down!
Port g1/3, and port g1/4 of SWITCH B are all shut down by ULDP, and there is notification
information on the CRT terminal of PC2.
%Oct 29 11:09:50 2007 A unidirectional link is detected! Port Ethernet1/3 need to be shutted
down!
%Oct 29 11:09:50 2007 Unidirectional port Ethernet1/3 shutted down!
%Oct 29 11:09:50 2007 A unidirectional link is detected! Port Ethernet1/4 need to be shutted
down!
%Oct 29 11:09:50 2007 Unidirectional port Ethernet1/4 shutted down!
7.4 ULDP Troubleshooting
Configuration Notice:
In order to ensure that ULDP can discover that the one of fiber ports has not connected or the
ports are incorrectly cross connected, the ports have to work in duplex mode and have the
same rate.
If the automatic negotiation mechanism of the fiber ports with one port misconnected decides
the working mode and rate of the ports, ULDP won’t take effect no matter enabled or not. In
such situation, the port is considered as “Down”.
In order to make sure that neighbors can be correctly created and unidirectional links can be
correctly discovered, it is required that both end of the link should enable ULDP, using the
same authentication method and password. At present, no password is needed on both ends.
The hello interval of sending hello messages can be changed (it is10 seconds by default and
ranges from 5 to 100 seconds) so that ULDP can respond faster to connection errors of links in
different network environments. But this interval should be less than 1/3 of the STP
convergence time. If the interval is too long, a STP loop will be generated before ULDP
discovers and shuts down the unidirectional connection port. If the interval is too short, the
network burden on the port will be increased, which means a reduced bandwidth.
ULDP does not handle any LACP event. It treats every link of TRUNK group (like Port-channal,
TRUNK ports) as independent, and handles each of them respectively.
ULDP does not compact with similar protocols of other vendors, which means users can not
use ULDP on one end and use other similar protocols on the other end.
ULDP function is disabled by default. After globally enabling ULDP function, the debug switch
can be enabled simultaneously to check the debug information. There are several DEBUG
commands provided to print debug information, such as information of events, state machine,