SIP深入学习---- 建立通讯

来源：互联网发布：男性家暴知乎编辑：程序博客网时间：2024/04/30 12:58

SIP 建立通讯的过程

1.用SIP来建立通讯通常需要有六个步骤:

(1)登记, 发起和定位用户.
(2)进行媒体协商 --通常采用SDP方式来携带媒体参数.
(3)由被叫方来决定是否接纳该呼叫.
(4)呼叫媒体流建立并交互.
(5)呼叫更改或处理.
(6)呼叫终止.

2.Registration - 登记

每当用户打开SIP终端时(如PC,IP PHONE), 将向＊＊＊＊＊/登记服务器发起登记过程

登记过程需要周期刷新

登记服务器将把SIP终端所登记的信息传送到位置服务器存放.

REGISTER sip:bell-tel.com SIP/2.0
Via: SIP/2.0/UDP saturn.bell-tel.com
From: sip:Watson@bell-tel.com
To: sip:Watson@bell-tel.com
Call-ID: 70710@saturn.bell-tel.com
CSeq: 1 REGISTER
Contact: <sip:Watson@saturn.bell-             tel.com:3890;transport=udp>
Expires: 7200

3.简单的 SIP 呼叫建立和拆除流程图

1.       INVITE sip:02220002@100.1.0.25;user=phone SIP/2.0
         Via: SIP/2.0/UDP 100.1.0.252
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>
         Call-ID: 3733973800@100.1.0.252
         CSeq: 1 INVITE
         Contact: <sip:02120001@100.1.0.252;user=phone;transport=udp>
         User-Agent: Cisco ATA v2.11 ata186 (0803a)
         Expires: 300
         Content-Length: 245
         Content-Type: application/sdp

         v=0
         o=02120001 573 573 IN IP4 100.1.0.252
         s=ATA186 Call
         c=IN IP4 100.1.0.252
         t=0 0
         m=audio 10000 RTP/AVP 0 4 8 101
         a=rtpmap:0 PCMU/8000/1
         a=rtpmap:4 G723/8000/1
         a=rtpmap:8 PCMA/8000/1
         a=rtpmap:101 telephone-event/8000
         a=fmtp:101 0-15

2.      SIP/2.0 100 Trying
         Via: SIP/2.0/UDP 100.1.0.252
         Call-ID: 3733973800@100.1.0.252
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>
         CSeq: 1 INVITE
         Content-Length: 0

3.      INVITE sip:02220002@100.2.0.2:5060;user=phone SIP/2.0
         Via: SIP/2.0/UDP 100.1.0.25:5060;branch=beb4b540-65a2ea80-f79d94fd-6870ff45-1
         Via: SIP/2.0/UDP 100.1.0.252
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>
         Call-ID: 3733973800@100.1.0.252
         CSeq: 1 INVITE
         Contact: <sip:02120001@100.1.0.252;user=phone;transport=udp>
         User-Agent: Cisco ATA v2.11 ata186 (0803a)
         Expires: 300
         Content-Length: 245
         Content-Type: application/sdp

         v=0
         o=02120001 573 573 IN IP4 100.1.0.252
         s=ATA186 Call
         c=IN IP4 100.1.0.252
         t=0 0
         m=audio 10000 RTP/AVP 0 4 8 101
         a=rtpmap:0 PCMU/8000/1
         a=rtpmap:4 G723/8000/1
         a=rtpmap:8 PCMA/8000/1
         a=rtpmap:101 telephone-event/8000
         a=fmtp:101 0-15

4.       SIP/2.0 100 Trying
         Via: SIP/2.0/UDP 100.1.0.25:5060;branch=beb4b540-65a2ea80-f79d94fd-6870ff45-1
         Via: SIP/2.0/UDP 100.1.0.252
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>
         Call-ID: 3733973800@100.1.0.252
         CSeq: 1 INVITE
         Content-Length: 0

5.       INVITE sip:02220002@100.2.0.8:5060 SIP/2.0
         Via: SIP/2.0/UDP 100.2.0.2:5060
         Via: SIP/2.0/UDP 100.1.0.25:5060;branch=beb4b540-65a2ea80-f79d94fd-6870ff45-1
         Via: SIP/2.0/UDP 100.1.0.252
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>
         CSeq: 1 INVITE
         Call-ID: 3733973800@100.1.0.252
         Content-Length: 245
         Contact: <sip:02120001@100.1.0.252;transport=udp;user=phone>
         Content-Type: application/sdp
         Expires: 300
         User-Agent: Cisco ATA v2.11 ata186 (0803a)
         Record-Route: <sip:02220002@100.2.0.2:5060;maddr=100.2.0.2>

         v=0
         o=02120001 573 573 IN IP4 100.1.0.252
         s=ATA186 Call
         c=IN IP4 100.1.0.252
         t=0 0
         m=audio 10000 RTP/AVP 0 4 8 101
         a=rtpmap:0 PCMU/8000/1
         a=rtpmap:4 G723/8000/1
         a=rtpmap:8 PCMA/8000/1
         a=rtpmap:101 telephone-event/8000
         a=fmtp:101 0-15

6.      SIP/2.0 100 Trying
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         Call-Id: 3733973800@100.1.0.252
         Cseq: 1 INVITE
         Via: SIP/2.0/UDP 100.2.0.2:5060
         Via: SIP/2.0/UDP 100.1.0.25:5060;branch=beb4b540-65a2ea80-f79d94fd-6870ff45-1
         Via: SIP/2.0/UDP 100.1.0.252
         Contact: sip:20002@100.2.0.8
         User-Agent: Pingtel/1.1.1 (VxWorks)
         Content-Length: 0


7.      SIP/2.0 180 Ringing
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         Call-Id: 3733973800@100.1.0.252
         Cseq: 1 INVITE
         Via: SIP/2.0/UDP 100.2.0.2:5060
         Via: SIP/2.0/UDP 100.1.0.25:5060;branch=beb4b540-65a2ea80-f79d94fd-6870ff45-1
         Via: SIP/2.0/UDP 100.1.0.252
         Contact: sip:20002@100.2.0.8
         User-Agent: Pingtel/1.1.1 (VxWorks)
         Content-Length: 0


8.      SIP/2.0 180 Ringing
         Via: SIP/2.0/UDP 100.1.0.25:5060;branch=beb4b540-65a2ea80-f79d94fd-6870ff45-1
         Via: SIP/2.0/UDP 100.1.0.252
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         Cseq: 1 INVITE
         Call-Id: 3733973800@100.1.0.252
         Content-Length: 0
         Contact: sip:20002@100.2.0.8
         User-Agent: Pingtel/1.1.1 (VxWorks)

9.      SIP/2.0 180 Ringing
         Via: SIP/2.0/UDP 100.1.0.252
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         CSeq: 1 INVITE
         Call-ID: 3733973800@100.1.0.252
         Content-Length: 0
         Contact: sip:20002@100.2.0.8
         User-Agent: Pingtel/1.1.1 (VxWorks)

10.    SIP/2.0 200 OK
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         Call-Id: 3733973800@100.1.0.252
         Cseq: 1 INVITE
         Content-Type: application/sdp
         Content-Length: 193
         Via: SIP/2.0/UDP 100.2.0.2:5060
         Via: SIP/2.0/UDP 100.1.0.25:5060;branch=beb4b540-65a2ea80-f79d94fd-6870ff45-1
         Via: SIP/2.0/UDP 100.1.0.252
         Record-Route: <sip:02220002@100.2.0.2:5060;maddr=100.2.0.2>
         Contact: sip:20002@100.2.0.8
         Allow: INVITE, ACK, CANCEL, BYE, REFER, OPTIONS, NOTIFY
         User-Agent: Pingtel/1.1.1 (VxWorks)

         v=0
         o=Pingtel 5 5 IN IP4 100.2.0.8
         s=phone-call
         c=IN IP4 100.2.0.8
         t=0 0
         m=audio 8766 RTP/AVP 0 8 101
         a=rtpmap:0 pcmu/8000/1
         a=rtpmap:8 pcma/8000/1
         a=rtpmap:101 telephone-event/8000/1

        11.      SIP/2.0 200 OK
         Via: SIP/2.0/UDP 100.1.0.25:5060;branch=beb4b540-65a2ea80-f79d94fd-6870ff45-1
         Via: SIP/2.0/UDP 100.1.0.252
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         Cseq: 1 INVITE
         Call-Id: 3733973800@100.1.0.252
         Content-Length: 193
         Allow: INVITE
         Allow: ACK
         Allow: CANCEL
         Allow: BYE
         Allow: REFER
         Allow: OPTIONS
         Allow: NOTIFY
         Contact: sip:20002@100.2.0.8
         Content-Type: application/sdp
         Record-Route: <sip:02220002@100.2.0.2:5060;maddr=100.2.0.2>
         User-Agent: Pingtel/1.1.1 (VxWorks)

         v=0
         o=Pingtel 5 5 IN IP4 100.2.0.8
         s=phone-call
         c=IN IP4 100.2.0.8
         t=0 0
         m=audio 8766 RTP/AVP 0 8 101
         a=rtpmap:0 pcmu/8000/1
         a=rtpmap:8 pcma/8000/1
         a=rtpmap:101 telephone-event/8000/1

     12. SIP/2.0 200 OK
         Via: SIP/2.0/UDP 100.1.0.252
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         CSeq: 1 INVITE
         Call-ID: 3733973800@100.1.0.252
         Content-Length: 193
         Allow: INVITE, ACK, CANCEL, BYE, REFER, OPTIONS, NOTIFY
         Contact: sip:20002@100.2.0.8
         Content-Type: application/sdp
         Record-Route: <sip:02220002@100.2.0.2:5060;maddr=100.2.0.2>
         User-Agent: Pingtel/1.1.1 (VxWorks)

         v=0
         o=Pingtel 5 5 IN IP4 100.2.0.8
         s=phone-call
         c=IN IP4 100.2.0.8
         t=0 0
         m=audio 8766 RTP/AVP 0 8 101
         a=rtpmap:0 pcmu/8000/1
         a=rtpmap:8 pcma/8000/1
         a=rtpmap:101 telephone-event/8000/1




13.    ACK sip:02220002@100.2.0.2 SIP/2.0
         Route: <sip:20002@100.2.0.8:5060>
         Via: SIP/2.0/UDP 100.1.0.252
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         Call-ID: 3733973800@100.1.0.252
         CSeq: 1 ACK
         User-Agent: Cisco ATA v2.11 ata186 (0803a)
         Content-Length: 0

14.      ACK sip:20002@100.2.0.8:5060 SIP/2.0
         Via: SIP/2.0/UDP 100.1.0.252
         From: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         To: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         CSeq: 1 ACK
         Call-ID: 3733973800@100.1.0.252
         Content-Length: 0
         User-Agent: Cisco ATA v2.11 ata186 (0803a)

15.      OPTIONS sip:02220002@100.2.0.2:5060;maddr=100.2.0.2 SIP/2.0
         Route: <sip:02120001@100.1.0.252;transport=udp;user=phone>
         From: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         To: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         Call-Id: 3733973800@100.1.0.252
         Cseq: 1 OPTIONS
         Accept-Language: en
         Supported: sip-cc, sip-cc-01, timer
         User-Agent: Pingtel/1.1.1 (VxWorks)
         Via: SIP/2.0/UDP 100.2.0.8
         Content-Length: 0

16.   SIP/2.0 200 Ok
         Via: SIP/2.0/UDP 100.2.0.8
         From: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         To: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         Call-ID: 3733973800@100.1.0.252
         Cseq: 1 OPTIONS
         Content-Length: 0

17.      BYE sip:02220002@100.2.0.2:5060;maddr=100.2.0.2 SIP/2.0
         Route: <sip:02120001@100.1.0.252;transport=udp;user=phone>
         From: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         To: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         Call-Id: 3733973800@100.1.0.252
         Cseq: 2 BYE
         Accept-Language: en
         Supported: sip-cc, sip-cc-01, timer
         User-Agent: Pingtel/1.1.1 (VxWorks)
         Via: SIP/2.0/UDP 100.2.0.8
         Content-Length: 0


18.    SIP/2.0 200 Ok
         Via: SIP/2.0/UDP 100.2.0.8
         From: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         To: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         Call-ID: 3733973800@100.1.0.252
         Cseq: 2 BYE
         Content-Length: 0


19.    BYE sip:02120001@100.1.0.252;transport=udp;user=phone SIP/2.0
         Via: SIP/2.0/UDP 100.2.0.2:5060
         Via: SIP/2.0/UDP 100.2.0.8
         From: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         To: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         Cseq: 2 BYE
         Call-Id: 3733973800@100.1.0.252
         Content-Length: 0
         Supported: sip-cc
         Supported: sip-cc-01
         Supported: timer
         Accept-Language: en
         User-Agent: Pingtel/1.1.1 (VxWorks)

20.   SIP/2.0 200 OK
         Via: SIP/2.0/UDP 100.2.0.2:5060
         Via: SIP/2.0/UDP 100.2.0.8
         From: <sip:02220002@100.1.0.25;user=phone>;tag=14502
         To: <sip:02120001@100.1.0.25;user=phone>;tag=1981486230
         Call-Id: 3733973800@100.1.0.252
         Cseq: 2 BYE
         Server: Cisco ATA v2.11 ata186 (0803a)
         Content-Length: 0