GB28181实现摄像头网页无插件直播、回放过程中设备状态分析

关于LiveGBS GB28181流媒体服务器的部署详见 https://www.liveqing.com/docs/download/LiveGBS.html。通过LiveGBS流媒体服务可以实现GB28181接入摄像头、硬盘录像机、其他支持GB28181的视频平台，实现网页无插件直播。
如下是GB28181注册成功后设备状态查询的信令分析：

1. 发送设备状态查询命令（服务>>设备）

MESSAGE sip:34020000001320000264@3402000000 SIP/2.0
Via: SIP/2.0/UDP 192.168.2.135:5060;rport;branch=z9hG4bK847293060
From: <sip:34020000002000000001@3402000000>;tag=603293060
To: <sip:34020000001320000264@3402000000>
Call-ID: 521293060
CSeq: 15 MESSAGE
Max-Forwards: 70
User-Agent: LiveQing
Content-Length: 167
Content-Type: Application/MANSCDP+xml

<?xml version="1.0" encoding="UTF-8"?>
<Query>
    <CmdType>DeviceStatus</CmdType>
    <SN>800293061</SN>
    <DeviceID>34020000001320000264</DeviceID>
</Query>

2. 设备端响应请求 （设备>>服务）

SIP/2.0 200 OK
Via: SIP/2.0/UDP 192.168.2.135:5060;rport=5060;branch=z9hG4bK847293060
From: <sip:34020000002000000001@3402000000>;tag=603293060
To: <sip:34020000001320000264@3402000000>;tag=1918280724
Call-ID: 521293060
CSeq: 15 MESSAGE
User-Agent: IP Camera
Content-Length: 0

3. 设备上传状态信息 （设备>>服务）

MESSAGE sip:34020000002000000001@3402000000 SIP/2.0
Via: SIP/2.0/UDP 192.168.2.64:5060;rport=5060;received=192.168.2.64;branch=z9hG4bK535315480
From: <sip:34020000001320000264@3402000000>;tag=1034018613
To: <sip:34020000002000000001@3402000000>
Call-ID: 1544085115
CSeq: 20 MESSAGE
Content-Type: Application/MANSCDP+xml
Max-Forwards: 70
User-Agent: IP Camera
Content-Length: 342

<?xml version="1.0" encoding="UTF-8"?>
<Response>
<CmdType>DeviceStatus</CmdType>
<SN>800293061</SN>
<DeviceID>34020000001320000264</DeviceID>
<Result>OK</Result>
<Online>ONLINE</Online>
<Status>OK</Status>
<DeviceTime>2019-08-07T13:56:27</DeviceTime>
<Alarmstatus Num="0">
</Alarmstatus>
<Encode>ON</Encode>
<Record>OFF</Record>
</Response>

4. 服务端响应 （服务>>设备）

SIP/2.0 200 OK
Via: SIP/2.0/UDP 192.168.2.64:5060;rport=5060;received=192.168.2.64;branch=z9hG4bK535315480
From: <sip:34020000001320000264@3402000000>;tag=1034018613
To: <sip:34020000002000000001@3402000000>;tag=32293130
CSeq: 20 MESSAGE
Call-ID: 1544085115
User-Agent: LiveQing
Content-Length: 0