Other reasons for label actions include:
MTU changes
LDP withdraws the previously assigned label, and re-signals the FEC with the new 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When a service manager command is issued to clear the labels, the labels are withdrawn, and new label mappings are issued.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When an SDP goes administratively down, the VC label associated with that SDP for each service is withdrawn.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, it is released.
VC type unsupported
When an unsupported VC type is received, the received label is released.