| | | | | | 下图中红色字体的为关键信令点 | | | | | | | | | | | | | | |
| 主叫UE | | eNB | | EPC | | IMS | | EPC | | eNB | | 被叫UE |
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| | | | | | 1.INVITE | | | | | | | | | | | | | | | 1、主叫UE高层协议发送INVITE到IMS |
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| | | 2.Server Request | | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | | | | | | | 2-3、主叫UE完成RRC连接,eNB向IMS发送INVITE,并在RRC Connection Setup中建立SRB1信令无线承载 |
| | | 3.RRC Proceure | | | Server Request | | | | | | | | | | | | | | |
| | | | | | INVITE | | | | | | | | | | | | | | |
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| | | 4.Security Proceure | | | | | | | | | | | | | | | | | | 4、主叫UE完成安全模式 |
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| | | 5.RRC Reconfig(QCI5) | | | | | | | | | | | | | | | | | | 5、主叫UE进行RRC重配,建立SRB2信令无线承载,恢复QCI9和QCI5承载,配置策略控制 |
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| | | | | | 6.Invite 100 Trying | | | | | | | | | | | | | | | 6、IMS收到主叫的INITE消息,发送INVITE100(TRYING)给主叫UE,用于响应INVITE消息。 |
| | | | | | | | | | | | | | | | | | | | | 注:INVITE消息中包含呼叫类型、主被叫的号码、主叫方支持的媒体类型和编码等 |
| | | | | | | | | | | | INVITE | | | 7.Paging | | | | | | 7、IMS向被叫EPC发送INVITE,被叫EPC开始寻呼被叫UE |
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| | | | | | | | | | | | | | | | | | 8.Server Request | | |
| | | | | | | | | | | | | | | | | | | | | 8-9、被叫UE完成RRC连接,在RRC Connection Setup中建立SRB1信令无线承载 |
| | | | | | | | | | | | | | | | | | 9.RRC Proceure | | |
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| | | | | | | | | | | | | | | 10.Security Proceure | | | | | | 10、被叫UE完成安全模式 |
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| | | | | | | | | | | | | | | | | | 11.RRC Reconfig(QCI5) | | | 11、被叫UE进行RRC重配,建立SRB2信令无线承载,恢复QCI9和QCI5承载,配置策略控制 |
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| | | | | | | | | | | | | | | 12.INVITE | | | | | | 12、EPC侧通过QCI=5的RB向被叫发送INVITE消息 |
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| | | | | | | | | | | | | | | 13.INVITE 100 | | | | | | 13、UE收到INVITE后,向IMS发送INVITE100消息进行响应 |
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| | | | | | | | | | | | | | | 14.INVITE 183 | | | | | | 14、被叫发送INVITE183消息给IMS,提示网络侧被叫已经做好资源预留,接下来建立专用承载QCI1 |
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| | | | | | | | | | | | | | | 15.EPS BEAR SETUP(QCI=1) | | | | | | 15、启动Precondition(资源预留)过程,并通知主叫自己所支持的媒体类型和编码,并建立起QCI=1的承载 |
| | | 16.EPS BEAR SETUP(QCI=1) | | | | | | | | | | | | | | | | | | 16、IMS收到被叫的INVITE183后,对主叫启动Precondition(资源预留)过程,通过EPC通知主叫SM层建立起QCI=1的承载 |
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| | | | | | 17.INVITE 183 | | | | | | | | | | | | | | | 17、IMS向主叫UE发送INVITE183消息,告诉主叫正在准备资源 |
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| | | | | | 18.PRACK | | | | | | | | | | | | | | | 18、主叫向IMS发送PRACK,告诉网络主叫正在等待资源 |
| | | | | | | | | | | | | | | | | | | | | 注:PRACK过程是一个预确认过程,主要为了防止会话超时及拥塞 |
| | | | | | | | | | | | | | | 19.PRACK | | | | | | 19、IMS向被叫发送PRACK,告诉被叫UE,主叫正在等待网络资源 |
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| | | | | | | | | | | | | | | 20.PRACK 200 | | | | | | 20、被叫收到PRACK后,向IMS返回PRACK200,表明网络资源已分配,QCI=1等承载已建立 |
| | | | | | 21.PRACK 200 | | | | | | | | | | | | | | | 21、IMS向主叫返回PRACK200,表明网络资源已分配,QCI=1等承载已建立 |
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| | | | | | 22.UPDATE | | | | | | | | | | | | | | | 22、主叫,向IMS发送UPDATE消息(在收到被叫的PRACK200,即QCI=1等承载已建立)以后,进行媒体格式协商过程 |
| | | | | | | | | | | | | | | 23.UPDATE | | | | | | 23、IMS向被叫UE发送UPDATE,进行媒体格式协商 |
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| | | | | | | | | | | | | | | 24.UPDATE 200 | | | | | | 24、被叫通过UPDATE200,向IMS返回协商结果 |
| | | | | | 25.UPDATE 200 | | | | | | | | | | | | | | | 25、IMS通过UPDATE200,向主叫UE返回协商结果 |
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| | | | | | | | | | | | | | | 26.INVITE 180(Ring) | | | | | | 26、被叫通过INVITE 180(Ring)告诉IMS,我已振铃 |