Manages PDUs

As a service to local application programs, CMIP services determines whether protocol data units (PDUs) are properly formed and exchanged in the proper order. This service frees application programs from having to verify the PDUs themselves.

A PDU can have several types of errors. These include:

A value is out of the legal range for the data type. The message is rejected.
A tag is unrecognized in a SET value or SEQUENCE value. The message is rejected.

If a PDU suffers from several of these errors at one time, the most severe errors are processed first. When the message fails to be decoded, CMIP services tries to decode the Remote Operations Service Element (ROSE) header for the message. If the header can be decoded, the message is rejected.

In some cases, if the header cannot be decoded, the association is ended. This should not happen unless the message is totally destroyed.

CMIP services understands the messages that are exchanged with object instances. It maintains the list of outstanding requests that require replies and enforces that the CMIP strings it receives are correct.

CMIP services does not always ensure that duplicate linked-replies are not received.