UDLD

UDLDtesting.txt

!UDLD sends frames to a special fake MAC address and it wants them echod back by the UDLD on the other device. 
!A unidirectional fiber failure should be simulatable with a MAC address filter. 
!UDLD only acts if a port enters bidirectional UDLD state before tranistioning to unidirectional. 
!
!Wait for bidirectional state, then: 
mac access-list extended UDLD_FILTER
  deny any host 0100.0ccc.cccc
  perm any
!
int G x/x
  mac access-group UDLD_FILTER in
!
!
!However, on some models, the filter doesn't work. The packets get to UDLD via CPU too early. 
!This is an alternate filter that works in at least some of those cases: 
!
mac access-list extended UDLD_MATCH
 permit any host 0100.0ccc.cccc
class-map UDLD_CLASS
 match access-group name UDLD_MATCH
 exit
policy-map UDLD_POLICY
 class UDLD_CLASS
 police 32000 conform-action drop exceed-action drop
 exit
!Wait for bidirectional state, then: 
int G x/x
 service-policy input UDLD_POLICY
 end
!
!