GB28181学习（十五）——流传输方式

前言

基于GB/T28181-2022版本，实时流的传输方式包括3种：

• UDP
• TCP被动
• TCP主动

UDP

流程

注意：

• m字段指定传输方式为RTP/AVP；

抓包

• SIP服务器发送INVITE请求；

INVITE sip:[email protected]:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.0.107:5060;rport;branch=xxx
Max-Forwards: 70
From: sip:[email protected]:5060;tag=xxx
To: sip:[email protected]:5060
Contact: <sip:[email protected]:5060>
Call-ID: xxx
CSeq: 18467 INVITE
Allow: INVITE, ACK, BYE, CANCEL, UPDATE, PRACK
Supported: 100rel
Subject: xxx:xx,xxx:xx
Content-Type: application/sdp
Content-Length:   211

v=0
o=xxx 0 0 IN IP4 192.168.0.107
s=Play
c=IN IP4 192.168.0.107
t=0 0
m=video 36000 RTP/AVP 96 98 97   # 36000为SIP服务数据接收端口
a=recvonly
a=rtpmap:96 PS/90000
a=rtpmap:98 H264/90000
a=rtpmap:97 MPEG4/90000
y=0100000001

• 设备返回200 OK；

SIP/2.0 200 OK
Call-ID: xxx
Contact: <sip:[email protected]:5060>
Content-Length: 226
Content-Type: application/sdp
CSeq: 18467 INVITE
From: <sip:[email protected]:5060>;tag=xxx
To: <sip:[email protected]:5060>;tag=xxx
User-Agent: SIP UAS V.2016.xxxx
Via: SIP/2.0/UDP 192.168.0.107:5060;rport=5060;branch=xxx

v=0
o=34020000001310000002 0 0 IN IP4 192.168.0.111
s=Play
i=VCam Live Video
c=IN IP4 192.168.0.111
t=0 0
m=video 9712 RTP/AVP 96     # 9712为设备端数据发送端口
a=sendonly
a=rtpmap:96 PS/90000
a=streamprofile:0
y=0100000001
f=v/0/0/0/0/0a/0/0/0

• SIP服务器返回ACK

ACK sip:[email protected]:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.0.107:5060;rport;branch=xxx
Max-Forwards: 70
From: sip:[email protected]:5060;tag=xxx
To: sip:[email protected]:5060;tag=xxx
Call-ID: xxx
CSeq: 18467 ACK
Content-Length:  0

TCP被动

流程

注意：

• m字段指定传输方式为TCP/RTP/AVP；
• sdp信息中增加"a=setup:passive"；
• SIP服务器启动端口监听，设备发起tcp连接请求；

抓包

• SIP服务器发送INVITE请求；

INVITE sip:[email protected]:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.0.107:5060;rport;branch=xxx
Max-Forwards: 70
From: sip:[email protected]:5060;tag=xxx
To: sip:[email protected]:5060
Contact: <sip:[email protected]:5060>
Call-ID: xxx
CSeq: 18480 INVITE
Allow: INVITE, ACK, BYE, CANCEL, UPDATE, PRACK
Supported: 100rel
Subject: xxx:xx,xxx:xx
Content-Type: application/sdp
Content-Length:   211

v=0
o=xxx 0 0 IN IP4 192.168.0.107
s=Play
c=IN IP4 192.168.0.107
t=0 0
m=video 36000 TCP/RTP/AVP 96 98 97 
a=recvonly
a=rtpmap:96 PS/90000
a=rtpmap:98 H264/90000
a=rtpmap:97 MPEG4/90000
a=setup:passive
y=0100000001

• 设备返回200 OK

SIP/2.0 200 OK
Call-ID: xxx
Contact: <sip:[email protected]:5060>
Content-Length: 264
Content-Type: application/sdp
CSeq: 18480 INVITE
From: <sip:[email protected]>;tag=xxx
To: <sip:[email protected]>;tag=xxx
User-Agent: SIP UAS V.2016.xxxx
Via: SIP/2.0/UDP 192.168.0.107:5060;rport=5060;branch=xxx

v=0
o=xxx 0 0 IN IP4 192.168.0.111
s=Play
i=VCam Live Video
c=IN IP4 192.168.0.111
t=0 0
m=video 9724 TCP/RTP/AVP 96    # 9724为设备端数据发送端口
a=sendonly
a=rtpmap:96 PS/90000           # 流数据为PS封装
a=streamprofile:0
a=setup:active                 # 设备为主动发送方
a=connection:new
y=0100000001
f=v/0/0/0/0/0a/0/0/0

• SIP服务器返回ACK

ACK sip:[email protected]:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.0.107:5060;rport;branch=xxx
Max-Forwards: 70
From: sip:[email protected]:5060;tag=xxx
To: sip:[email protected]:5060;tag=xxx
Call-ID: xxx
CSeq: 18480 ACK
Content-Length:  0

TCP主动

流程

注意：

• m字段指定传输方式为TCP/RTP/AVP；
• sdp信息中增加"a=setup:active"；
• 设备返回200 OK，报文的SDP信息中包含tcp监听端口；
• SIP服务器根据设备监听端口发起TCP连接请求；

抓包

• SIP服务器发送INVITE请求；

INVITE sip:[email protected]:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.0.107:5060;rport;branch=xxx
Max-Forwards: 70
From: sip:[email protected]:5060;tag=xxx
To: sip:[email protected]:5060
Contact: <sip:[email protected]:5060>
Call-ID: xxx
CSeq: 19100 INVITE
Allow: INVITE, ACK, BYE, CANCEL, UPDATE, PRACK
Supported: 100rel
Subject: xxx:xx,xxx:xx
Content-Type: application/sdp
Content-Length:   211

v=0
o=xxx 0 0 IN IP4 192.168.0.107
s=Play
c=IN IP4 192.168.0.107
t=0 0
m=video 38000 TCP/RTP/AVP 96 98 97 
a=recvonly
a=rtpmap:96 PS/90000
a=rtpmap:98 H264/90000
a=rtpmap:97 MPEG4/90000
a=setup:active
y=0100000001

• 设备返回200 OK

SIP/2.0 200 OK
Call-ID: xxx
Contact: <sip:[email protected]:5060>
Content-Length: 264
Content-Type: application/sdp
CSeq: 19100 INVITE
From: <sip:[email protected]>;tag=xxx
To: <sip:[email protected]>;tag=xxx
User-Agent: SIP UAS V.2016.xxxx
Via: SIP/2.0/UDP 192.168.0.107:5060;rport=5060;branch=xxx

v=0
o=xxx 0 0 IN IP4 192.168.0.111
s=Play
i=VCam Live Video
c=IN IP4 192.168.0.111
t=0 0
m=video 9704 TCP/RTP/AVP 96    # 9704为设备端监听
a=sendonly
a=rtpmap:96 PS/90000           # 流数据为PS封装
a=streamprofile:0
a=setup:passive                # 设备为被动接收方
a=connection:new
y=0100000001
f=v/0/0/0/0/0a/0/0/0

• SIP服务器返回ACK

ACK sip:[email protected]:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.0.107:5060;rport;branch=xxx
Max-Forwards: 70
From: sip:[email protected]:5060;tag=xxx
To: sip:[email protected]:5060;tag=xxx
Call-ID: xxx
CSeq: 19100 ACK
Content-Length:  0

• SIP服务器主动发起tcp连接