【5G核心网】5GC核心网之网元AMF

ゞ浴缸里的玫瑰 2023-02-23 12:16 3阅读 0赞

# AMF 基础 #

###    AMF: 接入及移动性管理功能 Access and Mobility Management Function TS 29518，以下功能： ###

>  *  \-终止RAN CP接口（N2）  Termination of RAN CP interface (N2)
>  *  \-终止NAS（N1），NAS加密和完整性保护  Termination of NAS (N1), NAS ciphering and integrity protection
>  *  \-注册管理  Registration management
>  *  \-连接管理  Connection management
>  *  \-可达性管理  Reachability management
>  *  \-移动性管理  Mobility Management
>  *  \-合法拦截  Lawful intercept
>  *  \-为UE和SMF之间的SM消息提供传输  Provide transport for SM messages between UE and SMF
>  *  \-用于路由SM消息的透明代理  Transparent proxy for routing SM messages
>  *  \-接入身份验证  Access Authentication
>  *  \-接入授权  Access Authorization
>  *  \-提供UE和SMSF SMS消息的传输  Provide transport for SMS messages between UE and SMSF
>  *  \-安全锚功能（SEAF）  Security Anchor Functionality (SEAF) as specified in TS 33.501
>  *  \-监管服务的定位服务管理  Location Services management for regulatory services
>  *  \-为UE和LMF之间以及RAN和LMF之间的位置服务消息提供传输  Provide transport for Location Services messages between UE and LMF as well as between RAN and LMF
>  *  \-用于与EPS互通的EPS 承载 ID分配  EPS Bearer ID allocation for interworking with EPS
>  *  \-UE移动事件通知  UE mobility event notification
>  *  \-支持控制面CIoT 5GS优化  Support for Control Plane CIoT 5GS Optimisation
>  *  \-支持用户面CIoT 5GS优化  Support for User Plane CIoT 5GS Optimisation
>  *  \-提供外部参数  Provisioning of external parameters (Expected UE Behaviour parameters or Network Configuration parameters).
>  *  \-支持特定的网络切片认证和鉴权  Support for Network Slice-Specific Authentication and Authorization

相当于 4GMME 的移动性管理功能，增加了 NAS 透传功能， 包括注册管理，连接管理，可达性管理，移动性管理，接入鉴权，接入授权

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pob25nbGluemhhbmc_size_16_color_FFFFFF_t_70][] 5G 核心网架构

N1 UE <--> AMF  NAS

N2 AN  <--> AMF  NGAP  TS 38.413 \[34\]  AN 节点和 AMF 之间的应用层协议

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pob25nbGluemhhbmc_size_16_color_FFFFFF_t_70 1][] Figure 4.1-1: Reference model – AMF

<table> Table 5.1-1 List of AMF Services 
 <tbody> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> Service Name </td> 
 <td style="vertical-align:top;width:166.6pt;"> Service Operations </td> 
 <td style="vertical-align:top;width:139.5pt;"> Operation Semantics </td> 
 <td style="vertical-align:top;width:108pt;"> Example Consumer(s) </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> Namf_Communication </td> 
 <td style="vertical-align:top;width:166.6pt;"> UEContextTransfer </td> 
 <td style="vertical-align:top;width:139.5pt;"> Request/Response </td> 
 <td style="vertical-align:top;width:108pt;"> Peer AMF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> RegistrationStatusUpdate </td> 
 <td style="vertical-align:top;width:139.5pt;"> Request/Response </td> 
 <td style="vertical-align:top;width:108pt;"> Peer AMF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> CreateUEContext </td> 
 <td style="vertical-align:top;width:139.5pt;"> Request/Response </td> 
 <td style="vertical-align:top;width:108pt;"> Peer AMF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> ReleaseUEContext </td> 
 <td style="vertical-align:top;width:139.5pt;"> Request/Response </td> 
 <td style="vertical-align:top;width:108pt;"> Peer AMF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> N1MessageNotify </td> 
 <td style="vertical-align:top;width:139.5pt;"> Subscribe/Notify &nbsp; </td> 
 <td style="vertical-align:top;width:108pt;"> Peer AMF, LMF, PCF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> N2InfoNotify </td> 
 <td style="vertical-align:top;width:108pt;"> LMF, AMF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> N1N2MessageSubscribe </td> 
 <td style="vertical-align:top;width:108pt;"> PCF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> N1N2MessageUnSubscribe </td> 
 <td style="vertical-align:top;width:108pt;"> PCF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> N1N2MessageTransfer </td> 
 <td style="vertical-align:top;width:139.5pt;"> Request/Response </td> 
 <td style="vertical-align:top;width:108pt;"> Peer AMF, SMF, SMSF, LMF, PCF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> N1N2TransferFailureNotification </td> 
 <td style="vertical-align:top;width:139.5pt;"> Subscribe/Notify </td> 
 <td style="vertical-align:top;width:108pt;"> SMF, SMSF, LMF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> NonUeN2MessageTransfer </td> 
 <td style="vertical-align:top;width:139.5pt;"> Request/Response </td> 
 <td style="vertical-align:top;width:108pt;"> Peer AMF, LMF, CBCF, PWS-IWF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> NonUeN2InfoSubscribe </td> 
 <td style="vertical-align:top;width:139.5pt;"> Subscribe/Notify &nbsp; </td> 
 <td style="vertical-align:top;width:108pt;"> CBCF, PWS-IWF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> NonUeN2InfoUnSubscribe </td> 
 <td style="vertical-align:top;width:108pt;"> CBCF, PWS-IWF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> NonUeN2InfoNotify </td> 
 <td style="vertical-align:top;width:139.5pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:108pt;"> LMF, CBCF, PWS-IWF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> EBIAssignment </td> 
 <td style="vertical-align:top;width:139.5pt;"> Request/Response </td> 
 <td style="vertical-align:top;width:108pt;"> SMF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> AMFStatusChangeSubscribe </td> 
 <td style="vertical-align:top;width:139.5pt;"> Subscribe / Notify </td> 
 <td style="vertical-align:top;width:108pt;"> SMF, PCF,&nbsp;NEF,&nbsp;SMSF, UDM </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> AMFStatusChangeUnSubscribe </td> 
 <td style="vertical-align:top;width:139.5pt;"> Subscribe / Notify </td> 
 <td style="vertical-align:top;width:108pt;"> SMF, PCF,&nbsp;NEF,&nbsp;SMSF, UDM </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> AMFStatusChangeNotify </td> 
 <td style="vertical-align:top;width:139.5pt;"> Subscribe / Notify </td> 
 <td style="vertical-align:top;width:108pt;"> SMF, PCF,&nbsp;NEF,&nbsp;SMSF, UDM </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> Namf_EventExposure </td> 
 <td style="vertical-align:top;width:166.6pt;"> Subscribe (see NOTE) </td> 
 <td style="vertical-align:top;width:139.5pt;"> Subscribe/Notify </td> 
 <td style="vertical-align:top;width:108pt;"> NEF, SMF, UDM </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> Unsubscribe (see NOTE) </td> 
 <td style="vertical-align:top;width:139.5pt;"> Subscribe/Notify </td> 
 <td style="vertical-align:top;width:108pt;"> NEF, SMF, UDM </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> Notify </td> 
 <td style="vertical-align:top;width:139.5pt;"> Subscribe/Notify </td> 
 <td style="vertical-align:top;width:108pt;"> NEF, SMF, UDM </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> Namf_MT </td> 
 <td style="vertical-align:top;width:166.6pt;"> EnableUEReachability </td> 
 <td style="vertical-align:top;width:139.5pt;"> Request/Response </td> 
 <td style="vertical-align:top;width:108pt;"> SMSF </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> ProvideDomainSelectionInfo </td> 
 <td style="vertical-align:top;width:139.5pt;"> Request/Response </td> 
 <td style="vertical-align:top;width:108pt;"> UDM </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> Namf_Location </td> 
 <td style="vertical-align:top;width:166.6pt;"> ProvidePositioningInfo </td> 
 <td style="vertical-align:top;width:139.5pt;"> Request/Response </td> 
 <td style="vertical-align:top;width:108pt;"> GMLC </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> EventNotify </td> 
 <td style="vertical-align:top;width:139.5pt;"> Subscribe / Notify </td> 
 <td style="vertical-align:top;width:108pt;"> GMLC </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;width:99.8pt;"> &nbsp; </td> 
 <td style="vertical-align:top;width:166.6pt;"> ProvideLocationInfo </td> 
 <td style="vertical-align:top;width:139.5pt;"> Request/Response </td> 
 <td style="vertical-align:top;width:108pt;"> UDM </td> 
 </tr> 
 <tr> 
 <td colspan="4" style="vertical-align:top;width:513.9pt;"> NOTE: A subscription applies for one UE, group of UE(s) or any UE. </td> 
 </tr> 
 </tbody> 
</table>

# 1. Namf\_communication 服务 #

Namf\_communication 开启 NF 与 UE 通信，可以通过 N1 NAS 消息，或者通过 AN（支持 UE 和非 UE），该服务允许 NF 和 UE AN 通信定义如下：

>  *  提供为传输到 UE 的 N1 消息的服务操作
>  *  允许网元从 UE 为指定的 N1 消息的通知订阅以及取消订阅
>  *  允许网元从 AN 关于指定信息的通知订阅和取消订阅
>  *  提供用于向 AN 发起 N2 消息的服务操作
>  *  安全上下文管理
>  *  UE 信息管理以及传输

*  \- UEContextTransfer
 *  \- RegistrationStatusUpdate
 *  \- N1N2MessageTransfer (UE Specific)
 *  \- N1N2TransferFailureNotification (UE Specific)
 *  \- N1N2MessageSubscribe (UE Specific)
 *  \- N1N2MessageUnsubscribe (UE Specific)
 *  \- N1MessageNotify (UE Specific)
 *  \- N2InfoNotify (UE Specific)
 *  \- NonUeN2MessageTransfer
 *  \- NonUeN2InfoSubscribe
 *  \- NonUeN2INfoUnsubscribe
 *  \- N2InfoNotify
 *  \- EBIAssignment
 *  \- CreateUEContext
 *  \- ReleaseUEContext
 *  \- AMFStatusChangeSubscribe
 *  \- AMFStatusChangeUnsubscribe
 *  \- AMFStatusChangeNotify

##   1.1. API Definitions ##

**\{apiRoot\}/<apiName>/<apiVersion>/<apiSpecificResourceUriPart>**

- The \{apiRoot\} shall be set as described in 3GPP TS 29.501 \[5\].

- The <apiName>** **shall be "namf-comm".

- The <apiVersion> shall be "v1".

- The <apiSpecificResourceUriPart> shall be set as described in clause 6.1.3

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pob25nbGluemhhbmc_size_16_color_FFFFFF_t_70 2][]

**                                     Figure 6.1.3.1-1: Resource URI structure of the Namf\_Communication API**

<table> 
 <tbody> 
 <tr> 
 <td> Resource name </td> 
 <td> Resource URI </td> 
 <td> HTTP method or custom operation </td> 
 <td> Description (Mapped Service Operations) </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;"> Individual ueContext &nbsp; </td> 
 <td style="vertical-align:top;"> /ue-contexts/{ueContextId} &nbsp; </td> 
 <td style="vertical-align:top;"> &nbsp; </td> 
 <td style="vertical-align:top;"> &nbsp; </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;"> PUT </td> 
 <td style="vertical-align:top;"> CreateUEContext </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;"> /ue-contexts/{ueContextId}/release &nbsp; </td> 
 <td style="vertical-align:top;"> &nbsp; release (POST) </td> 
 <td style="vertical-align:top;"> ReleaseUEContext </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;"> /ue-contexts/{ueContextId}/assign-ebi &nbsp; </td> 
 <td style="vertical-align:top;"> assign-ebi (POST) &nbsp; </td> 
 <td style="vertical-align:top;"> EBIAssignment </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;"> /ue-contexts/{ueContextId}/transfer </td> 
 <td style="vertical-align:top;"> transfer (POST) &nbsp; </td> 
 <td style="vertical-align:top;"> UEContextTransfer </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;"> &nbsp; </td> 
 <td style="vertical-align:top;"> /ue-contexts/{ueContextId}/transfer-update </td> 
 <td style="vertical-align:top;"> transfer-update (POST) &nbsp; </td> 
 <td style="vertical-align:top;"> RegistrationStatusUpdate </td> 
 </tr> 
 <tr> 
 <td> n1N2Message collection </td> 
 <td> /ue-contexts/{ueContextId}/n1-n2-messages </td> 
 <td style="vertical-align:top;"> POST </td> 
 <td style="vertical-align:top;"> N1N2MessageTransfer </td> 
 </tr> 
 <tr> 
 <td> N1N2 Subscriptions Collection for Individual UE Contexts </td> 
 <td> /ue-contexts/{ueContextId}/n1-n2-messages/subscriptions </td> 
 <td style="vertical-align:top;"> POST </td> 
 <td style="vertical-align:top;"> N1N2MessageSubscribe </td> 
 </tr> 
 <tr> 
 <td> N1N2 Individual Subscription </td> 
 <td> /ue-contexts/{ueContextId}/n1-n2-messages/subscriptions/{subscriptionId} </td> 
 <td style="vertical-align:top;"> DELETE </td> 
 <td style="vertical-align:top;"> N1N2MessageUnSubscribe </td> 
 </tr> 
 <tr> 
 <td> n1N2Message transfer status notification callback </td> 
 <td> {n1N2MessageTransferFailureNotifyUrl} (NF Service Consumer provided callback reference) </td> 
 <td style="vertical-align:top;"> POST </td> 
 <td style="vertical-align:top;"> N1N2Transfer Failure Notification </td> 
 </tr> 
 <tr> 
 <td> subscriptions collection </td> 
 <td> /subscriptions </td> 
 <td style="vertical-align:top;"> POST </td> 
 <td style="vertical-align:top;"> AMFStatusChangeSubscribe </td> 
 </tr> 
 <tr> 
 <td> individual subscription </td> 
 <td> /{subscriptionId} </td> 
 <td style="vertical-align:top;"> PUT </td> 
 <td style="vertical-align:top;"> AMFStatusChangeSubscribe </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;"> DELETE </td> 
 <td style="vertical-align:top;"> AMFStatusChangeUnSubscribe </td> 
 </tr> 
 <tr> 
 <td style="vertical-align:top;"> Non UE N2Messages collection&nbsp; </td> 
 <td> /non-ue-n2-messages/transfer </td> 
 <td style="vertical-align:top;"> transfer (POST) &nbsp; &nbsp; </td> 
 <td style="vertical-align:top;"> NonUEN2MessageTransfer </td> 
 </tr> 
 <tr> 
 <td> Non UE N2Messages Subscriptions collection </td> 
 <td> /non-ue-n2-messages/subscriptions </td> 
 <td style="vertical-align:top;"> POST </td> 
 <td style="vertical-align:top;"> NonUEN2InfoSubscribe </td> 
 </tr> 
 <tr> 
 <td> Non UE N2 Message Notification Individual Subscription </td> 
 <td> /non-ue-n2-messages/subscriptions/{n2NotifySubscriptionId} </td> 
 <td style="vertical-align:top;"> DELETE </td> 
 <td style="vertical-align:top;"> NonUEN2InfoUnsubscribe </td> 
 </tr> 
 </tbody> 
</table>

Table 6.1.3.1-1: Resources and methods overview

##   1.2 UE Context Operations  ##

###    1.2.1 UEContextTransfer ###

>         UE 发起注册或者移动注册触发 UEContextTransfer，NF（网元）服务消费者设置原因属性 “INIT\_REG” / "MOBI\_REG"，以及包括完成性保护注册请求消息，也会触发 UEContextTransfer 
> 
>          当目标 AMF接收注册请求，其 UE 的 5G-GUTI 和正在服务的 AMF 不一样，也就是与上次注册的 AMF 更改了，新 AMF 向旧 AMF 发起 *UEContextTransfer* 获取 UE 上下文，比如 UE 的 SUPI 和 MM 上下文

![20200713153230193.png][]

###    1.2.2 RegistrationStatusUpdate ###

###    1.2.3 CreateUEContext ###

###    1.2.4 ReleaseUEContext ###

##   1.3 UE Specific N1N2 Message Operations ##

###    1.3.1 N1N2MessageTransfer ###

>     NF 服务使用者使用 N1N2MessageTransfer 服务操作通过以下步骤，通过 AMF 将 N1 和/或 N2 信息传输到 UE 和/或 5G-AN：
> 
>     -  网络触发的服务请求（请参阅3GPP TS 23.502 \[3\]的第4.2.3.3节）
> 
>     -  PDU会话建立（请参阅3GPP TS 23.502 \[3\]的4.3.2节）
> 
>     -  PDU会话修改（请参见3GPP TS 23.502 \[3\]的第4.3.3节）
> 
>     -  PDU会话版本（请参阅3GPP TS 23.502 \[3\]的4.3.4节）
> 
>     -

Resource URI: \{apiRoot\}/namf-comm/<apiVersion>/ue-contexts/\{ueContextId\}/n1-n2-messages

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pob25nbGluemhhbmc_size_16_color_FFFFFF_t_70 3][]**Table 6.1.3.5.3.1-1: Data structures supported by the**  **POST** ** Request Body on this resource**

##   1.4 Non-UE N2 Message Operations ##

##   1.5 AMF Status Change Operations ##

###    1.5.1 AMFStatusChangeSubscribe     ###

NF 服务使用者使用此服务操作来订阅 AMF 的状态更改。在以下过程中使用 AMFStatusChangeSubscribe 服务操作：

>   -  AMF 计划的删除程序（请参阅3GPP TS 23.501 \[2\]，第5.21.2.2节）

**    1.5.1.1 Creation of a subscription**

此服务操作将创建一个订阅，以便 NF 服务使用者可以在 AMF 的状态更改时请求通知。

Resource URI:\{apiRoot\}/namf-comm/<apiVersion>/subscriptions

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pob25nbGluemhhbmc_size_16_color_FFFFFF_t_70 4][] Figure 5.2.2.5.1.1-1 NF Service Consumer Subscription to Notifications

![20201204141901514.png][] Table 6.1.3.6.3.1-2: Data structures supported by the POST Request Body on this resource

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pob25nbGluemhhbmc_size_16_color_FFFFFF_t_70 5][] \{apiRoot\}/namf-comm/<apiVersion>/subscriptions

# 2. Namf\_EventExposure Service #

AMF 可以作为服务生产者提供此服务，以使 NF 能够自己或代表另一个 NF 订阅事件通知并获得事件通知。 已知的服务使用者是 NEF，SMF，UDM。 另见 3GPP TS 23.502 \[3\]的第4.15.1、4.15.3.2、4.15.4.2和5.2.2.3.1节。

Namf\_EventExposure Service 提供以下事件：

>   -  Event: Location-Report
> 
>   -  Event: Presence-In-AOI-Report
> 
>   -  Event: Time-Zone-Report
> 
>   -  Event: Access-Type-Report
> 
>   -  Event: Registration-State-Report
> 
>   -  Event: Connectivity-State-Report
> 
>   -  Event: Reachability-Report
> 
>   -  Event: Communication-Failure-Report
> 
>   -  Event: UEs-In-Area-Report
> 
>   -  Loss-of-Connectivity

###    3.1 Subscribe ###

NF服务消费者（例如，NEF）使用该服务操作来为一个 UE，一组 UE 或任何 UE 订阅事件。

**    3.1.1 Creation of a subscription**

订阅服务操作由 NF 服务使用者（例如 NF NEF）调用。 NEF在需要创建订阅以监视至少一个与 AMF相 关的事件时，针对 AMF。 NF 务使用者可以订阅一个订阅中的多个事件。 订阅可以与一个 UE，一组 UE 或任何 UE 相关联。

# 3. Namf\_MT Service #

Namf\_MT服务允许 NF 请求与向目标 UE 发送 MT 信令或数据的能力有关的信息。 以下是此 NF 服务的关键功能

>   -  如果 UE 处于空闲状态并在进入 CM-CONNECTED 状态后响应其他 NF，则寻呼 UE。
> 
>   -  如果 UE 处于连接状态，则响应请求者 NF。
> 
>   -  向消费者 NF 提供 IMS 语音的终止域选择信息。

###    3.1 EnableUEReachability ###

在以下过程中使用 EnableUEReachability 服务操作：

>   -  NAS上的MT SMS处于CM-IDLE状态（请参阅3GPP TS 23.502 \[3\]，条款4.13.3.6），或处于CM-CONNECTED状态（请参阅3GPP TS 23.502 \[2\]，条款4.13.3.7）。

###    3.2 ProvideDomainSelectionInfo ###

NF 服务消费者（例如UDM）将调用 ProvideDomainSelectionInfo 服务操作以获取用于终止 IMS 语音域选择的 UE 信息，包括以下信息：

>   -  指示在 PS 会话上支持 IMS 语音；
> 
>   -  与 UE 的最后一次无线电联系的时间戳；  
> 
>   -  当前 Accss type 和 RAT type

# 4. Namf\_Location Service #

NF 服务使用者将 Namf\_Location 服务用于请求 AMF 以发起定位请求并提供位置信息。 它还用于随后向 NF 服务使用者通知位置更改事件。 以下是此 NF 服务的关键功能：

>   -  允许 NF 请求目标 UE 的当前地理测量和可选的城市定位。
> 
>   -  允许 NF 通知与紧急会话相关的事件信息。
> 
>   -  允许 NF 请求与目标 UE 的位置相对应的网络提供的位置信息（NPLI）和/或本地时区。

###    4.1 ProvidePositioningInfo ###

在以下过程中使用 ProvidePositioningInfo 服务操作：

>   -  没有 UDM 查询的 5GC-MT-LR 过程（请参阅3GPP TS 23.502 \[3\]，第4.13.5.2条）
> 
>   -  5GC-MT-LR 过程（请参阅3GPP TS 23.502 \[3\]，第4.13.5.3条）
> 
>   -  从 NG-RAN 切换紧急会话的位置连续性（请参阅3GPP TS 23.502 \[3\]，第4.13.5.7条）

###    4.2 EventNotify ###

在以下过程中使用 EventNotify 服务操作：

>   -  5GC-NI-LR 程序（请参阅3GPP TS 23.502 \[3\]第4.13.5.1条）
> 
>   -  从 NG-RAN 切换紧急会话的位置连续性（请参阅3GPP TS 23.502 \[3\]，第4.13.5.7条）

###    4.3 ProvideLocationInfo ###

ProvideLocationInfo 服务操作允许 NF 服务使用者（例如UDM）请求目标 UE 的网络提供的位置信息（NPLI）。

***名词解释：***

**SCTP**，Stream Control Transmission Protocol

**PLMN**，Public Land Mobile Network  公共陆地移动网 ，一般特指某个运营商的网络覆盖区域

**MCC**，Mobile Country Code

**MNC**，Mobile Network Code

**GUAMI**，Globally Unique AMF Identifier 全球唯一的  AMF 标识符   ***<GUAMI> = <MCC><MNC><AMF Identifier>***

**TAI**，Tracking Area Identity    跟踪区域标识

**GUTI**，Globally Unique Temporary UE Identity  全局唯一的临时UE标识，目的减少在通信中显示使用UE的永久性标识，提升安全性

**SUPI，**Subscription Permanent Identifier 用户的唯一永久身份标志

**LMF，** Location Management Function

### 参考： ###

TS 29.518  **5G System; Access and Mobility Management Services;** **Stage 3**(Release 15)

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