Label actions can also occur for the following reasons:
MTU changes — LDP withdraws the previously assigned label and resignals the FEC with the new Maximum Transmission Unit (MTU) in the interface parameter
clear labels — when a service manager command is issued to clear the labels, the labels are withdrawn and new label mappings are issued
SDP down — when an SDP goes administratively down, the VC label associated with that SDP for each service is withdrawn
memory allocation failure — if there is no memory to store a received label, the received label is released
VC type unsupported — when an unsupported VC type is received, the received label is released