6.4 Usage of DMA-UNITDATA primitive

6.4 Usage of DMA-UNITDATA primitive
When clauses 6.2 and 6.3 refer to the DMCC "sending a PDU", the DMCC shall give the PDU to layer 2 in a
DMA-UNITDATA request primitive. Layer 2 then transmits the PDU the appropriate number of times using the
appropriate transmission method. Similarly, when the DMCC receives a PDU, the message is delivered by layer 2 in a
DMA-UNITDATA indication primitive.




When sending a PDU, the DMCC shall construct the DM-SDU (as defined in clause 9) for inclusion in the
DMA-UNITDATA request and shall provide the "message type" (e.g. DM-SETUP, DM-RELEASE,
DM-SDS UDATA) as a parameter in the primitive. It shall also provide destination addressing information when
required. For example, for a DM-SETUP, DM-SETUP PRES, DM-CONNECT ACK, DM-OCCUPIED,
DM-SDS UDATA, DM-SDS DATA, DM-TX CEASED, DM-RELEASE or DM-INFO PDU, the destination address is
usually the TSI of the called DM-MS(s).

PDU를 전송할 때, DMCC 는 DMA-UNITDATA request 내에 포함하기 위해서 DM-SDU 조립해야한다. 그리고 메시지 타입을 프리미티브 내에 파라메터에 제공해야한다.

그것은 필요할 때 목적지 주소 정보도 제공해야한다. 예로 DM-SETUP, DM-SETUP PRES 나 DM-INFO PDU 들에 목적지 주소는 CALLED DM-MS에 TSI 이다.


The DMCC shall also include the following parameters in the DMA-UNITDATA request primitive when appropriate:

a) for a DM-SETUP, DM-SETUP PRES, DM-CONNECT ACK, DM-OCCUPIED, DM-TX CEASED,
DM-SDS UDATA, DM-SDS DATA, DM-TX REQUEST or DM-PREEMPT PDU, the DMCC shall include
the call priority;
b) for a DM-SETUP, DM-SETUP PRES, DM-CONNECT, DM-CONNECT ACK or DM-OCCUPIED PDU, the
DMCC shall include the circuit mode type;
c) for a DM-SDS UDATA or DM-SDS DATA PDU, the DMCC shall indicate whether the short data is being
sent as part of an ongoing circuit mode call (SDS transaction type);
d) for a DM-SDS UDATA, DM-SDS DATA, or DM-SDS ACK PDU, the DMCC shall indicate whether an FCS
is included within the PDU (FCS flag);
e) for a DM-TX CEASED PDU, the DMCC shall indicate whether the recent user priority facility is invoked and
may indicate the required reservation time following this traffic transmission;
f) for a DM-PREEMPT or DM-PRE ACCEPT PDU, the DMCC shall indicate whether the pre-emption relates to
the ongoing call or to a new call, and shall indicate the type of pre-emption;
g) for a DM-SETUP, DM-SETUP PRES, DM-SDS UDATA or DM-SDS DATA PDU, the DMCC shall indicate
whether the message is being sent after pre-emption / changeover;
h) for a DM-SDS DATA PDU, the DMCC shall indicate whether the message is to be sent as an immediate
retransmission;
j) for a DM-TX REQUEST PDU, the DMCC shall indicate whether the changeover request has been held during
occupation and whether it is a recent user request;
k) for a DM-SDS UDATA or DM-INFO PDU sent during circuit mode occupation, the DMCC shall indicate the
stealing priority;
l) for a DM-SDS UDATA or DM-INFO PDU, the DMCC shall indicate the number of transmissions required.
Items a) to f) shall be mapped by layer 2 into the MAC PDU header, whereas items g) to l) shall be used locally within
layer 2.