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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

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 List 9.3.1.17	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 List 9.3.1.191	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 DRX 9.3.1.90		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 Name 9.3.3.21		-
>>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