sip会话流程以及sip介绍（3）

1、mtk_ims_mo_sip报文交互流程

log:

步骤1:ATD触发MO呼叫尝试
步骤2:VDM选择ADS到IMS。
步骤3:触发VoLTE UA来设置MO调用。
步骤4:SIP信息到P-CSCF进行MO呼叫设置和协商
步骤5:在VoLTE情况下确认专用承载与此调用尝试的QoS条件匹配。
步骤6:更新数据路径的媒体参数。在VoWiFi中， WFCA信号被handle RTP on WiFi。
步骤7:将呼叫状态传递给IMC，并激活媒体流。
步骤8:URC来指示Framework的call状态。

2、mtk_ims_MT_sip报文交互流程

步骤1:VoLTE UA接收SIP消息为MT呼叫尝试和协商P-CSCF为MT呼叫设置。
步骤2:在VoLTE情况下确认专用承载与此调用尝试的QoS条件匹配
步骤3:更新数据路径的媒体参数。在VoWiFi中，也给WFCA发信号来处理WiFi上的RTP
步骤4、5:传递MT call attempt到Framework，等待用户接受。
步骤6:通知VoLTE UA接受MT调用并完成调用设置
步骤7:SIP消息到P-CSCF完成MT设置
步骤8:将呼叫状态传递给IMC，激活媒体流
步骤9:URC来指示框架的调用状态

//receive,request,INVITE
[AT_URC p31,ch1]+ESIPCPI: 0,1,0,1,0,""
[AT_URC p31,ch1]+EAIC: 1,"13267945631",129,20,102,0
[AT_RX p33,ch3]AT+EAIC=0,1,102
//send ,response,INVITE
[AT_URC p31,ch1]+ESIPCPI: 1,0,1,1,183,""
[ATCI_AT_I_0 s33]AT+EIMSCI=1,0,0 //IMS 开启，LTE
//MT,IMS_VOICE_CALL,国内呼叫
[AT_URC p31,ch1]+ECPI: 1,0,0,1,1,20,"13267945631",129,"<tel:13267945631>"
 [AT_URC p31,ch1]+ESIPCPI: 1,1,0,13,0,""    //receive request PRACK
[AT_URC p31,ch1]+ESIPCPI: 1,0,1,13,200,""    //send response PRACK
[AT_URC p31,ch1]+ESIPCPI: 1,1,0,3,0,""        //receive request UPDATE
[AT_URC p31,ch1]+ESIPCPI: 1,0,1,3,200,""    //send response UPDATE
[AT_URC p31,ch1]+ESIPCPI: 1,0,1,1,180,""    //send response INVITE
[AT_URC p31,ch1]+CRING: VOICE               //180 Ring
[AT_URC p31,ch1]+ESIPCPI: 1,0,1,1,200,""    //send response INVITE
[AT_URC p31,ch1]+ECPI: 1,132,0,1,1,20,"13267945631",129,"<tel:13267945631>"
[AT_URC p31,ch1]+ECPI: 1,6,0,1,1,20,"13267945631",129,"<tel:13267945631>"
[AT_URC p31,ch1]+ESIPCPI: 1,1,0,6,0,""     // receive request    ACK
[AT_URC p31,ch1]+ESIPCPI: 1,1,0,1,0,""     // receive request    INVITE
[AT_URC p31,ch1]+ESIPCPI: 1,0,1,1,200,""    // send response INVITE
[AT_URC p31,ch1]+ESIPCPI: 1,1,0,6,0,""    // receive request    ACK
[AT_URC p31,ch1]+EIMSCMODE: 1,20,0,3,"<tel:13267945631>",2 //接132的电话
[AT_RX p50,ch6]AT+CHLD=11    //释放特定的active call 1
[AT_URC p31,ch1]+ECPI: 1,133,0,1,1,20,"13267945631",129,"<tel:13267945631>",16
[ATCI_AT_I_0 s33]AT+EIMSCI=0,0,0[AT_URC p31,ch1]+ESIPCPI: 1,1,0,7,0,"" // receive request BYE[AT_URC p31,ch1]+ESIPCPI: 1,0,1,7,200,""  //send response BYE
[AT_RX p33,ch3]AT+CEER
[AT_TX p33,ch3]+CEER: 16,CM_NORMAL_CALL_CLR
小结：　 1、不管是MT/MO，最后BYE SIP信令可能由主动呼叫方发起，也有可能由被动呼叫方发起。

 2、info 为100 Trying的INVITE SIP信令在AT下发的时候没有对应的AT指令。