A MEP can detect and report a number of defects, and multiple defects can be present at the same time. These defects are: bDefRDICCM(1) A remote MEP is reported the RDI bit in its last CCM. bDefMACstatus(2) Either some remote MEP is reporting its Interface Status TLV as not isUp, or all remote MEPs are reporting a Port Status TLV that contains some value other than psUp. bDefRemoteCCM(3) The MEP is not receiving valid CCMs from at least one of the remote MEPs. bDefErrorCCM(4) The MEP has received at least one invalid CCM whose CCM Interval has not yet timed out. bDefXconCCM(5) The MEP has received at least one CCM from either another MAID or a lower MD Level whose CCM Interval has not yet timed out.