Manual
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84 
Ethernet1/1 need to be shutted 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! 
8.4 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. 










