User's Manual

10-6
%Oct 29 11:09:50 2007 A unidirectional link is detected! Port Ethernet1/0/1 need to be shut down!
%Oct 29 11:09:50 2007 Unidirectional port Ethernet1/0/1 shut down!
%Oct 29 11:09:50 2007 A unidirectional link is detected! Port Ethernet1/0/2 need to be shut down!
%Oct 29 11:09:50 2007 Unidirectional port Ethernet1/0/2 shut down!
Port g1/0/3, and port g1/0/4 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 Ethernet1/0/3 need to be shut down!
%Oct 29 11:09:50 2007 Unidirectional port Ethernet1/0/3 shut down!
%Oct 29 11:09:50 2007 A unidirectional link is detected! Port Ethernet1/0/4 need to be shut down!
%Oct 29 11:09:50 2007 Unidirectional port Ethernet1/0/4 shut down!
10.4 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-channel, 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, errors and
messages. Different types of message information can also be printed according to different
parameters.
 The Recovery timer is disabled by default and will only be enabled when the users have configured
recovery time (30-86400 seconds).
 Reset command and reset mechanism can only reset the ports automatically shut down by ULDP. The