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1. NG SETUP过程
1.1 NG SETUP定义
NG Setup过程用来交换NG-RAN节点和AMF在NG-C接口上正确互操作所需的应用程序级数据。该程序为TNL关联开始运行后触发的第一个NGAP程序。该过程使用非UE相关的信令。
此过程将擦除两个节点中的任何现有应用程序级配置数据，将其替换为接收到的数据，并清除NG-RAN节点上的AMF过载状态信息。如果NG-RAN节点和AMF不同意保留UE上下文，则此过程还会像NG重置过程一样重新初始化NGAP UE相关上下文，并擦除两个节点中的所有相关信令连接。
1.2 NG建立成功
编辑
NG SETUP：成功运行
NG-RAN向AMF发送NG SETUP REQUEST消息来建立NG连接。AMF以NG SETUP RESPONSE消息进行响应。
如果NG SETUP REQUEST消息中Supported TA List字段包含的Configured TAC Indication设置为“true”，AMF可以考虑向此NG-RAN节点发送NG-C信令。
如果NG SETUP REQUEST消息中的UE Retention Information 设置为“ues-retained”，AMF将保留现有的UE上下文和信令连接，并将NG SETUP RESPONSE消息中的UE Retention Information 设置为“ues-retained”。
AMF应将Backup AMF Name包含在NG SETUP RESPONSE消息的Served GUAMI List中。如果NG-RAN支持的话，NG-RAN在执行AMF重选时，应先考虑Backup AMF Name所指示的AMF。
如果NG SETUP RESPONSE消息中包含有GUAMI Type，则NG-RAN节点应存储收到的值，将其用于进一步的AMF选择。
如果NG SETUP REQUEST消息中包含RAN Node Name，则AMF可以使用该Name作为NG-RAN节点的可读名称。
如果NG SETUP RESPONSE消息中包含AMF Name，则NG-RAN节点可以使用该Name作为AMF的可读名称。
如果NG SETUP REQUEST消息中包含NB-IoT Default Paging DRX，AMF应将其考虑在内进行寻呼。
如果NG SETUP REQUEST消息中包含RAT Information，AMF应按照TS 23.502【10】中的规定处理该信息。
1.3 NG建立失败
编辑
NG设置：操作失败
如果AMF不能接受NG Setup，则回应NG SETUP FAILURE消息，并携带相应的原因值。
如果NG SETUP FAILURE消息包括Time to Wait，则NG-RAN节点至少应该等待所指示的时间，然后再向同一AMF重新启动NG Setup过程。
1.4 异常情况
如果NG-RAN节点通过发送包括PLMN标识的NG SETUP REQUEST消息来启动该过程，并且AMF不识别由NG-RAN节点提供的PLMN，则AMF将以相应的原因值来拒绝NGSetup过程。
2.NG SETUP信令结构
2.1 NG SETUP REQUEST结构
| IE/Group Name | Presence | Range | IE type and reference | Semantics description | Criticality | Assigned Criticality |
| Message Type | M | 9.3.1.1 | YES | reject | ||
| Global RAN Node ID | M | 9.3.1.5 | YES | reject | ||
| RAN Node Name | O | PrintableString(SIZE(1..150, …)) | YES | ignore | ||
| Supported TA List | 1 | Supported TAs in the NG-RAN node. | YES | reject | ||
| >Supported TA Item | 1..<maxnoof**TACs> | - | ||||
| >>TAC | M | 9.3.3.10 | Broadcast TAC | - | ||
| >>Broadcast PLMN List | 1 | - | ||||
| >>>Broadcast PLMN Item | 1..<maxnoof**BPLMNs> | - | ||||
| >>>>PLMN Identity | M | 9.3.3.5 | Broadcast PLMN | - | ||
| >>>>TAI Slice Support List | M | Slice Support List9.3.1.17 | Supported S-NSSAIs per TAC, per PLMN or per SNPN. | - | ||
| >>>>NPN Support | O | 9.3.3.44 | If the NID IE is included, it identifies a SNPN together with the PLMN Identity IE. | YES | reject | |
| >>>>Extended TAI Slice Support List | O | Extended Slice Support List9.3.1.191 | Additional Supported S-NSSAIs per TAC, per PLMN or per SNPN. | YES | reject | |
| >>Configured TAC Indication | O | 9.3.3.50 | YES | ignore | ||
| >>RAT Information | O | 9.3.1.125 | RAT information associated with the TAC of the indicated PLMN(s). | YES | reject | |
| Default Paging DRX | M | Paging DRX9.3.1.90 | YES | ignore | ||
| UE Retention Information | O | 9.3.1.117 | YES | ignore | ||
| NB-IoT Default Paging DRX | O | 9.3.1.137 | YES | ignore | ||
| Extended RAN Node Name | O | 9.3.1.193 | YES | ignore |
2.2 NG SETUP RESPONSE 结构
| IE/Group Name | Presence | Range | IE type and reference | Semantics description | Criticality | Assigned Criticality |
| Message Type | M | 9.3.1.1 | YES | reject | ||
| AMF Name | M | 9.3.3.21 | YES | reject | ||
| Served GUAMI List | 1 | YES | reject | |||
| >Served GUAMI Item | 1..<maxnoof****ServedGUAMIs> | - | ||||
| >>GUAMI | M | 9.3.3.3 | - | |||
| >>Backup AMF Name | O | AMF Name9.3.3.21 | - | |||
| >>GUAMI Type | O | ENUMERATED (native, mapped, …) | YES | ignore | ||
| Relative AMF Capacity | M | 9.3.1.32 | YES | ignore | ||
| PLMN Support List | 1 | YES | reject | |||
| >PLMN Support Item | 1..<maxnoof**PLMNs> | - | ||||
| >>PLMN Identity | M | 9.3.3.5 | - | |||
| >>Slice Support List | M | 9.3.1.17 | Supported S-NSSAIs per PLMN or per SNPN. | - | ||
| >>NPN Support | O | 9.3.3.44 | If NID IE is included, it identifies a SNPN together with the PLMN Identity IE. | YES | reject | |
| >>Extended Slice Support List | O | 9.3.1.191 | Additional Supported S-NSSAIs per PLMN or per SNPN. | YES | reject | |
| >>Onboarding Support | O | ENUMERATED (true, ...) | Indication of onboarding support. | YES | ignore | |
| Criticality Diagnostics | O | 9.3.1.3 | YES | ignore | ||
| UE Retention Information | O | 9.3.1.117 | YES | ignore | ||
| IAB Supported | O | ENUMERATED (true, ...) | Indication of support for IAB. | YES | ignore | |
| Extended AMF Name | O | 9.3.3.51 | YES | ignore |
| Range bound | Explanation |
| maxnoofServedGUAMIs | Maximum no. of GUAMIs served by an AMF. Value is 256. |
| maxnoofPLMNs | Maximum no. of PLMNs per message. Value is 12. |
2.3 NG SETUP FAILURE 结构
| IE/Group Name | Presence | Range | IE type and reference | Semantics description | Criticality | Assigned Criticality |
| Message Type | M | 9.3.1.1 | YES | reject | ||
| Cause | M | 9.3.1.2 | YES | ignore | ||
| Time to Wait | O | 9.3.1.56 | YES | ignore | ||
| Criticality Diagnostics | O | 9.3.1.3 | YES | ignore |
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