CLP - Cell Loss Priority

A 1 bit field in the ATM cell header that determines whether or not a 
given cell should be dropped by network equipment during periods of
congestion.  This field's values appear below.

0 - Indicates that the cell should be treated with a high priority
    and should not be dropped during periods of congestion.

1 - Indicates that the cell should be treated with a low priority
    and should be dropped, if needed, during periods of congestion.


See also - ATM UNI Cell Structure