The procedures specified in the subclause apply to those messages which pass the checks described in this subclause.
This subclause also specifies procedures for the handling of unknown, unforeseen, and erroneous UPDS data by the receiving entity. These procedures are called
"error handling procedures", but in addition to providing recovery mechanisms for error situations they define a compatibility mechanism for future extensions of the UPDS.
Subclause D.8.1 to
Subclause D.8.8 shall be applied in order of precedence.
Detailed error handling procedures in the network are implementation dependent and may vary from PLMN to PLMN. However, when extensions of UPDS are developed, networks are assumed to have the error handling which is indicated in this subclause as mandatory (
"shall") and that is indicated as strongly recommended (
"should").
Also, the error handling of the network is only considered as mandatory or strongly recommended when certain thresholds for errors are not reached during a dedicated connection.
For definition of semantical and syntactical errors see
subclause 11.4.2 of TS 24.007.
If the UE or the network receives a UPDS message with message type not defined for the UPDS or not implemented by the receiver, it shall ignore the UPDS message.
If the UE receives a message not compatible with the UPDS state, the UE shall ignore the UPDS message.
If the network receives a message not compatible with the UPDS state, the network actions are implementation dependent.
The UE shall ignore all IEs unknown in a message which are not encoded as
"comprehension required" (see
TS 24.007).
The network shall take the same approach.
The UE shall ignore all out of sequence IEs in a message which are not encoded as
"comprehension required" (see
TS 24.007).
The network should take the same approach.
If an information element with format T, TV, TLV, or TLV-E is repeated in a message in which repetition of the information element is not specified in
subclause D.5, the UE shall handle only the contents of the information element appearing first and shall ignore all subsequent repetitions of the information element. When repetition of information elements is specified, the UE shall handle only the contents of specified repeated information elements. If the limit on repetition of information elements is exceeded, the UE shall handle the contents of information elements appearing first up to the limit of repetitions and shall ignore all subsequent repetitions of the information element.
The network should follow the same procedures.
The UE shall treat all optional IEs that are syntactically incorrect in a message as not present in the message.
The network shall take the same approach.
When upon receipt of a UPDS message the UE diagnoses a
"missing conditional IE" error or an
"unexpected conditional IE" error, or when it receives a UPDS message containing at least one syntactically incorrect conditional IE, the UE shall ignore the message.
When the network receives a message and diagnoses a
"missing conditional IE" error or an
"unexpected conditional IE" error or when it receives a message containing at least one syntactically incorrect conditional IE, the network shall either:
-
try to treat the message (the exact further actions are implementation dependent); or
-
ignore the message.
When a message with semantically incorrect contents is received, the UE shall perform the foreseen reactions of the procedural part of
subclause D.2. If, however no such reactions are specified, the UE shall ignore the message.
The network should follow the same procedure.