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NATO UNCLASSIFIED
STANAG 5066: PROFILE FOR MARITIME HF DATA COMMUNICATION
V1.0.2
The first field is common to all S_PDUs. It is called “TYPE” and identifies the type of the
S_PDU.
The other fields are described below for each S_PDU type and defined in more detail in
Figure A-4:
Type :
“0” = DATA S_PDU
Encoding :
S_PCI
U_PDU
TYPE
(=0)
PRIORITY
SOURCE
SAP ID
DEST.
SAP ID
CLIENT DELIVERY
CONFIRM REQRD
TTD
Description :
This S_PDU is transmitted by the Subnetwork Interface Sublayer in order to send
client data to a remote peer sublayer. This S_PDU consists of two parts. The first part
is the S_PCI (Subnetwork Interface Sublayer Protocol Control Information) and
represents the overhead added by the sublayer. The second part is the actual client
data (U_PDU). The first field of the S_PCI is “TYPE”. It is equal to 0 and identifies
the S_PDU as being of type DATA. The second field is “PRIORITY” and represents
the priority of the client’s U_PDU. The third second field of the S_PCI is the
“SOURCE SAP ID” and identifies the client of the transmitting peer which sent the
data. The fourth third field is the “DESTINATION SAP ID” and identifies the client
of the receiving peer which must take delivery of the data. There is no need to encode
the source and destination node addresses in the S_PDU as this information is
relayed between the peers by the underlying sublayers. The fourth field is
“PRIORITY” and represents the priority of the client’s U_PDU. The fifth field is
“TTD” and represents the TimeToDie for this U_PDU. The “DESTINATION SAP
ID”, “PRIORITY” and “TTD” fields are copied directly from the corresponding
arguments of the S_UNIDATA_REQUEST primitive submitted by the client.
The fifth final field of the S_PCI is shown in the figure above as “CLIENT
DELIVERY CONFIRM REQUIRED”. The field is made up of 4 bits, one for
delivery confirmation, one indicating the presence of a valid TTD, and two reserved;
see figure A-4(a) for a more detailed description. This field The “CLIENT
DELIVERY CONFIRM REQUIRED” bit can take the values “YES” (=1) or “NO”
(=0). The value of this bit field will be set according to the Service Type requested by
the sending client during binding (see S_BIND_REQUEST primitive) or according
to the Delivery Mode requested explicitly for this U_PDU (see
S_UNUIDATA_REQUEST Primitive). If this field has the value of “YES”, the
receiving peer should confirm to the transmitting peer the successful delivery of the
U_PDU to the destination client. Upon receiving a DATA S_PDU, the receiving peer
must attempt to deliver the U_PDU to the destination client by issuing a
S_UNIDATA_INDICATION, or a S_EXPEDITED_UNIDATA_INDICATION. The
last field of the S_PCI is “TTD” and represents the TimeToDie for this U_PDU. The
“DESTINATION SAP ID”, “PRIORITY” and “TTD” fields are copied directly from
the corresponding arguments of the S_UNIDATA_REQUEST primitive submitted by
the client.
Type :
“1” = DATA DELIVERY CONFIRM
Encoding :
NATO UNCLASSIFIED
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