The encoding of the UADP NetworkMessage is specified in Table 73.
The NetworkMessageContentMask setting of the Publisher controls the flags in the fields UADPFlags and ExtendedFlags1. The SecurityMode setting of the Publisher controls the security enabled flag of the ExtendedFlags1. The setting of the flags shall not change until the configuration of the Publisher is changed.
Table 73 – UADP NetworkMessage
|
Name |
Type |
Description |
|
UADPVersion |
Bit[0-3] |
Bit range 0-3: Version of the UADP NetworkMessage. The UADPVersion for this specification version is 1. |
|
UADPFlags |
Bit[4-7] |
Bit 4: PublisherId enabled If the PublisherId is enabled, the type of PublisherId is indicated in the ExtendedFlags1 field. Bit 5: GroupHeader enabled Bit 6: PayloadHeader enabled Bit 7: ExtendedFlags1 enabledThe bit shall be false, if ExtendedFlags1 is 0. |
|
ExtendedFlags1 |
Byte |
The ExtendedFlags1 shall be omitted if bit 7 of the UADPFlags is false. If the field is omitted, the Subscriber shall handle the related bits as false. Bit range 0-2: PublisherId Type 000 The PublisherId is of DataType Byte This is the default value if ExtendedFlags1 is omitted 001 The PublisherId is of DataType UInt16 010 The PublisherId is of DataType UInt32 011 The PublisherId is of DataType UInt64 100 The PublisherId is of DataType String 101 Reserved 11x Reserved 111 Reserved Bit 3: DataSetClassId enabled Bit 4: Security enabled If the SecurityMode is SIGN_1 or SIGNANDENCRYPT_2, this flag is set, message security is enabled and the SecurityHeader is contained in the NetworkMessage header. If this flag is not set, the SecurityHeader is omitted. Bit 5: Timestamp enabled Bit 6: PicoSeconds enabled Bit 7: ExtendedFlags2 enabled The bit shall be false, if ExtendedFlags2 is 0. |
|
ExtendedFlags2 |
Byte |
The ExtendedFlags2 shall be omitted if bit 7 of the ExtendedFlags1 is false. If the field is omitted, the Subscriber shall handle the related bits as false. Bit 0: Chunk message defined in in 7.2.2.2.4. Bit 1: PromotedFields enabled Promoted fields can only be sent if the NetworkMessage contains only one DataSetMessage. Bit range 2-4: UADP NetworkMessage type 000 NetworkMessage with DataSetMessage payload defined in 7.2.2.2.4. If the ExtendedFlags2 field is not provided, this is the default NetworkMessage type. 001 NetworkMessage with discovery request payload defined in 7.2.2.3.4. 010 NetworkMessage with discovery response payload defined in 7.2.2.4.2. 011 Reserved 1xxReserved Bit 5: Reserved Bit 6: Reserved Bit 7: Reserved for further extended flag fields |
|
PublisherId |
Byte[*] |
The PublisherId shall be omitted if bit 4 of the UADPFlags is false. The Id of the Publisher that sent the data. Valid DataTypes are UInteger and String. The DataType is indicated by bits 0-2 of the ExtendedFlags1. A Subscriber can skip NetworkMessages from Publishers it does not expect NetworkMessages from. |
|
DataSetClassId |
Guid |
The DataSetClassId associated with the DataSets in the NetworkMessage. All DataSetMessages in the NetworkMessage shall have the same DataSetClassId. The DataSetClassId shall be omitted if bit 3 of the ExtendedFlags1 is false. |
|
GroupHeader |
|
The group header shall be omitted if bit 5 of the UADPFlags is false. |
|
GroupFlags |
Byte |
Bit 0: WriterGroupId enabled Bit 1: GroupVersion enabled Bit 2: NetworkMessageNumber enabled Bit 3: SequenceNumber enabled Bits 4-6: Reserved Bit 7: Reserved for further extended flag fields |
|
WriterGroupId |
UInt16 |
Unique id for the WriterGroup in the Publisher. A Subscriber can skip NetworkMessages from WriterGroups it does not expect NetworkMessages from. This field shall be omitted if bit 0 of the GroupFlags is false. |
|
GroupVersion |
VersionTime |
Version of the header and payload layout configuration of the NetworkMessages sent for the group. This field shall be omitted if bit 1 of the GroupFlags is false. |
|
NetworkMessage Number |
UInt16 |
Unique number of a NetworkMessage across the combination of PublisherId and WriterGroupId within one PublishingInterval. The number is needed if the DataSetMessages for one group are split into more than one NetworkMessage in a PublishingInterval. The value 0 is invalid. This field shall be omitted if bit 2 of the GroupFlags is false. |
|
SequenceNumber |
UInt16 |
Sequence number for the NetworkMessage. This field shall be omitted if bit 3 of the GroupFlags is false. |
|
PayloadHeader |
Byte [*] |
The payload header depends on the UADP NetworkMessage Type flags defined in the ExtendedFlags2 bit range 0-3. The default is DataSetMessage if the ExtendedFlags2 field is not enabled. The PayloadHeader shall be omitted if bit 6 of the UADPFlags is false. The PayloadHeader is not contained in the payload but it is contained in the unencrypted NetworkMessage header since it contains information necessary to filter DataSetMessages on the Subscriber side. |
|
Timestamp |
DateTime |
The time the NetworkMessage was created. The Timestamp shall be omitted if bit 5 of ExtendedFlags1 is false. The PublishingInterval, the SamplingOffset the PublishingOffset and the Timestamp and PicoSeconds in the NetworkMessage header shall use the same time base. |
|
PicoSeconds |
UInt16 |
Specifies the number of 10 picoseconds (1,0 e-11 seconds) intervals which shall be added to the Timestamp. The PicoSeconds shall be omitted if bit 6 of ExtendedFlags1 is false. |
|
PromotedFields |
|
The PromotedFields shall be omitted if bit 4 of the ExtendedFlags2 is false. If the PromotedFields are provided, the number of DataSetMessages in the Network Message shall be one. |
|
Size |
UInt16 |
Total size in Bytes of the Fields contained in the PromotedFields. |
|
Fields |
BaseDataType[ ] |
Array of promoted fields. The size, order and DataTypes of the fields depend on the settings in the FieldMetaData of the DataSetMetaData associated with the DataSetMessage contained in the NetworkMessage. |
|
SecurityHeader |
|
The security header shall be omitted if bit 4 of the ExtendedFlags1 is false. |
|
SecurityFlags |
Byte |
Bit 0: NetworkMessage Signed Bit 1: NetworkMessage Encrypted Bit 2: SecurityFooter enabled Bit 3: Force key reset This bit is set if all keys will be made invalid. It is set until the new key is used. The publisher must give subscribers a reasonable time to request new keys. The minimum time is five times the KeepAliveTime configured for the corresponding PubSub group. This flag is typically set if all keys are invalidated to exclude Subscribers, that no longer have access to the keys. Bit range 4-7: Reserved |
|
SecurityTokenId |
IntegerId |
The ID of the security token that identifies the security key in a SecurityGroup. The relation to the SecurityGroup is done through DataSetWriterIds contained in the NetworkMessage. |
|
NonceLength |
Byte |
The length of the Nonce used to initialize the encryption algorithm. |
|
MessageNonce |
Byte [NonceLength] |
A number used exactly once for a given security key. For a given security key a unique nonce shall be generated for every NetworkMessage. The rules for constructing the MessageNonce are defined for the UADP Message Security in 7.2.2.2.3. |
|
SecurityFooterSize |
UInt16 |
The size of the SecurityFooter. The security footer size shall be omitted if bit 2 of the SecurityFlags is false. |
|
Payload |
Byte [*] |
The payload depends on the UADP NetworkMessage Type flags defined in the ExtendedFlags2 bit range 2-5. |
|
SecurityFooter |
Byte [*] |
Optional security footer shall be omitted if bit 2 of the SecurityFlags is false. The content of the security footer is defined by the SecurityPolicy. |
|
Signature |
Byte [*] |
The signature of the NetworkMessage. |