Rules for the source and destination fields in the string

When messages are received from CMIP services through the API (on indications and confirmations), the following rules apply:

If the msg_type field in the API header is API_MSG, the src-type field in the string header is set to 1 (assoc-handle) and the src field contains the association handle over which the message arrived.
If the msg_type field in the API header is not API_MSG, the source data is not present.
If the local identifier in the API header refers to a subtree manager and the message is not targeted for that subtree manager, the dest-type field in the string is full-dn and the dest field contains the distinguished name of the object instance that is supposed to receive the message.

The application program does not normally build the src-type, src, dest-type, and dest portions of the string, but instead relies on MIBSendCmipRequest and MIBSendCmipResponse functions to build this portion of the string.

The src-type and src fields in the string header need to be provided only if the object needs to override the distinguished name associated with the registered object that is building the message.

The only acceptable src-type is distinguished name (0), which is the default. If the src field is provided and it contains a distinguished name that is different from the provider, the message contains a source override. Only a subtree manager can specify a source name to override the source name in the string header. If an application program that is not a subtree manager specifies a source, the message is flagged with an error.

The dest-type and dest fields are not required. However, these fields can be used to explicitly address messages when the syntax of the message does not contain routing information or when the routing information is not understood by CMIP services. If the CMIP standard is being used, explicit destination information is not required because the destination is given in the managedObjectInstance field.

The same does not apply, however, to OSI responses prompted by an indication and containing the same invoke identifier as the indication. When an object sends a response, it must provide the association handle from the indication that prompted the response.

Messages received by an object instance do not contain the dest-type and dest fields.

The msg field in the string header contains the formatted string. The string must begin with an ASN.1 module name and an ASN.1 syntax name. For all CMIP flows, the module name is CMIP-1 because CMIP-1 is the name of the ASN.1 module that defines the syntaxes used for CMIP flows.

Following the module name is the type name. The module name and type name must be separated by exactly one period; no other characters can be placed between these names. The remainder of the message is defined by the ASN.1 syntax for the module and type specified.