IMS和SIP系统中用户信息（SUSCRIBE）相当于无线网络协议中的“测量控制”和“信息请求”；要求其他网元报告状态或事件；
通知（NOTIFY）与无线网络中的”测量报告“或”信息反馈“相当；它们都是根据用户的请求进行报告的；--具体定义参见” RFC3265 Session Initiation Protocol (SIP)-Specific Event Notification) “；
1.用户信息和通知流程
2.用户(SUSCRIBE)信息 内容
Event | Description | Reference |
| reg | Request for IMS/SIP Registration Status(注册状态检查） | RFC 3680 |
| presence | Request for presence information (commonly used in RCS) | RFC 3856 |
| winfo | Request for Watcher information (commonly used in RCS) | RFC 3857 |
| xcap-diff | Request for Xcap-Diff information (commonly used in RCS) | RFC 3875 |
3. 通知（NOTIFY）内容
当出现错误代码(如 481, 400, 500)或在CSCF中发生问题时，通过发送通知”NOTIFY“告知具体问题原因；详细内容参见”RFC3265 3.2.4. Subscriber NOTIFY Behavior" ；
| Description |
| active | It means the subscription is accepted (in most case, authorized as well) |
| pending | It means the subscription has been received by the notifier, but there is insufficient policy information to grant or deny the subscription yet |
| terminated | It means the subscription is terminated and this can specify as a reason code as follows |
| deactivated | This mean that the subscription ended (terminated) but the subscriber (UE) SHOULD retry with a new subscription immediately. |
| probation | This mean that the subscription ended (terminated) but the client SHOULD retry at some time later. |
| rejected | This mean that the subscription ended (terminated) due to change in authorization policy. The client SHOULD NOT retry. |
| timeout | This mean that the subscription ended (terminated) because it is not refreshed before it expired. The client MAY retry immediately. |
| giveup | This mean that the subscription ended (terminated) because the notifier could not obtain authorization in time |
| noresource | This mean that the subscription ended (terminated) because the resource being monitored is no longer available. |
3.报文举例
Step 1 : SUBSCRIBE -----------------------------------
SUBSCRIBE sip:+[email]11234567890@test.3gpp.com[/email] SIP/2.0
Via: SIP/2.0/UDP 10.133.202.46:50997;branch=z9hG4bK2968d27245f17c7bcae38c31991bfdaa
Max-Forwards: 70
Contact: <sip:+[email]11234567890@10.133.202.46[/email]:50997>;+sip.instance="<urn:gsma:imei:00440113-904785-0>"
To: <sip:+[email]11234567890@test.3gpp.com[/email]>
From: <sip:+[email]11234567890@test.3gpp.com[/email]>;tag=210a54
Call-ID: [email]d57a0b04-[email]785ba328-[email]13a4d876@10.133.202.46[/email][/email][/email]
CSeq: 14534 SUBSCRIBE
Expires: 600000
User-Agent: IM-client/OMA1.0 DUT-IMS
Event: reg
Accept: application/reginfo+xml
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp="0010100010000000"
P-Preferred-Identity: <sip:+[email]11234567890@test.3gpp.com[/email]>
Content-Length: 0
Step 2 : 200 OK -----------------------------------
SIP/2.0 200 OK
Via: SIP/2.0/UDP 10.133.202.46:50997;branch=z9hG4bK2968d27245f17c7bcae38c31991bfdaa
From: <sip:+[email]11234567890@test.3gpp.com[/email]>;tag=210a54
To: <sip:+[email]11234567890@test.3gpp.com[/email]>;tag=987654321
Call-ID: [email]d57a0b04-[email]785ba328-[email]13a4d876@10.133.202.46[/email][/email][/email]
CSeq: 14534 SUBSCRIBE
Expires: 600000
Contact: <sip:10.133.202.47:5060>
Record-Route: <sip:10.133.202.47;lr>
Content-Length: 0
Step 3 : NOTIFY -----------------------------------
NOTIFY sip:+[email]11234567890@test.3gpp.com[/email] SIP/2.0
Via: SIP/2.0/UDP 10.133.202.47:5060;branch=z9hG4bK-d1e4c4961ca9d523ae76b67e088589cd
Call-ID: [email]d57a0b04-[email]785ba328-[email]13a4d876@10.133.202.46[/email][/email][/email]
From: <sip:+[email]11234567890@test.3gpp.com[/email]>;tag=987654321
To: <sip:+[email]11234567890@test.3gpp.com[/email]>;tag=210a54
Subscription-State: active;expires=600000
Event: reg
CSeq: 14534 NOTIFY
Contact: <sip:10.133.202.47:5060>
Max-Forwards: 70
Content-Type: application/reginfo+xml
Content-Length: 340
<?xml version="1.0" encoding="UTF-8"?>
<reginfo xmlns="urn:ietf:params:xml:ns:reginfo" version="0" state="full">
<registration aor="sip:+[email]11234567890@test.3gpp.com[/email]" id="12345" state="active">
<contact id="100" state="active" event="registered" expires="600000">
<uri>sip:+[email]11234567890@10.133.202.46[/email]:50997</uri>
</contact>
</registration>
</reginfo>
Step 4 : 200 OK -----------------------------------
SIP/2.0 200 OK
Via: SIP/2.0/UDP 10.133.202.47:5060;branch=z9hG4bK-d1e4c4961ca9d523ae76b67e088589cd
Max-Forwards: 70
Contact: <sip:+[email]11234567890@10.133.202.46[/email]:50997>;+sip.instance="<urn:gsma:imei:00440113-904785-0>"
To: <sip:+[email]11234567890@test.3gpp.com[/email]>;tag=210a54
From: <sip:+[email]11234567890@test.3gpp.com[/email]>;tag=987654321
Call-ID: [email]d57a0b04-[email]785ba328-[email]13a4d876@10.133.202.46[/email][/email][/email]
CSeq: 14534 NOTIFY
Allow: NOTIFY,SUBSCRIBE
Content-Length: 0
原文来自：http://www.sharetechnote.com/
整理：kangguoying20200925
"5G(NR)网络中MIB消息及案例”已在微信公众号"跟着老康学5G"中推出，敬请关注！
关注楼主