一个Sip会话的例子

本例子是一个基本的SIP四边传送，U1->P1->P2->U2，使用proxy来传送。摘自RFC3261。

 

F1 INVITE Alice -> atlanta.com proxy

INVITE sip:bob@biloxi.com SIP/2.0

Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8

Max-Forwards: 70

To: Bob <sip:bob@biloxi.com>

From: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

CSeq: 314159 INVITE

Contact: <sip:alice@pc33.atlanta.com>

Content-Type: application/sdp

Content-Length: 142

(Alice’s SDP not shown)

F2 100 Trying atlanta.com proxy -> Alice

SIP/2.0 100 Trying

Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8

;received=192.0.2.1

To: Bob <sip:bob@biloxi.com>

From: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

CSeq: 314159 INVITE

Content-Length: 0

F3 INVITE atlanta.com proxy -> biloxi.com proxy

INVITE sip:bob@biloxi.com SIP/2.0

Via: SIP/2.0/UDP bigbox3.site3.atlanta.com;branch=z9hG4bK77ef4c2312983.1

Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8

;received=192.0.2.1

Max-Forwards: 69

To: Bob <sip:bob@biloxi.com>

From: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

CSeq: 314159 INVITE

Contact: <sip:alice@pc33.atlanta.com>

Content-Type: application/sdp

Content-Length: 142

(Alice’s SDP not shown)

F4 100 Trying biloxi.com proxy -> atlanta.com proxy

SIP/2.0 100 Trying

Via: SIP/2.0/UDP bigbox3.site3.atlanta.com;branch=z9hG4bK77ef4c2312983.1

;received=192.0.2.2

Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8

;received=192.0.2.1

To: Bob <sip:bob@biloxi.com>

From: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

CSeq: 314159 INVITE

Content-Length: 0

F5 INVITE biloxi.com proxy -> Bob

INVITE sip:bob@192.0.2.4 SIP/2.0

Via: SIP/2.0/UDP server10.biloxi.com;branch=z9hG4bK4b43c2ff8.1

Via: SIP/2.0/UDP bigbox3.site3.atlanta.com;branch=z9hG4bK77ef4c2312983.1

;received=192.0.2.2

Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8

;received=192.0.2.1

Max-Forwards: 68

To: Bob <sip:bob@biloxi.com>

From: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

CSeq: 314159 INVITE

Contact: <sip:alice@pc33.atlanta.com>

Content-Type: application/sdp

Content-Length: 142

(Alice’s SDP not shown)

F6 180 Ringing Bob -> biloxi.com proxy

SIP/2.0 180 Ringing

Via: SIP/2.0/UDP server10.biloxi.com;branch=z9hG4bK4b43c2ff8.1

;received=192.0.2.3

Via: SIP/2.0/UDP bigbox3.site3.atlanta.com;branch=z9hG4bK77ef4c2312983.1

;received=192.0.2.2

Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8

;received=192.0.2.1

To: Bob <sip:bob@biloxi.com>;tag=a6c85cf

From: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

Contact: <sip:bob@192.0.2.4>

CSeq: 314159 INVITE

Content-Length: 0

F7 180 Ringing biloxi.com proxy -> atlanta.com proxy

SIP/2.0 180 Ringing

Via: SIP/2.0/UDP bigbox3.site3.atlanta.com;branch=z9hG4bK77ef4c2312983.1

;received=192.0.2.2

Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8

;received=192.0.2.1

To: Bob <sip:bob@biloxi.com>;tag=a6c85cf

From: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

Contact: <sip:bob@192.0.2.4>

CSeq: 314159 INVITE

Content-Length: 0

F8 180 Ringing atlanta.com proxy -> Alice

SIP/2.0 180 Ringing

Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8

;received=192.0.2.1

To: Bob <sip:bob@biloxi.com>;tag=a6c85cf

From: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

Contact: <sip:bob@192.0.2.4>

CSeq: 314159 INVITE

Content-Length: 0

F9 200 OK Bob -> biloxi.com proxy

SIP/2.0 200 OK

Via: SIP/2.0/UDP server10.biloxi.com;branch=z9hG4bK4b43c2ff8.1

;received=192.0.2.3

Via: SIP/2.0/UDP bigbox3.site3.atlanta.com;branch=z9hG4bK77ef4c2312983.1

;received=192.0.2.2

Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8

;received=192.0.2.1

To: Bob <sip:bob@biloxi.com>;tag=a6c85cf

From: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

CSeq: 314159 INVITE

Contact: <sip:bob@192.0.2.4>

Content-Type: application/sdp

Content-Length: 131

(Bob’s SDP not shown)

F10 200 OK biloxi.com proxy -> atlanta.com proxy

SIP/2.0 200 OK

Via: SIP/2.0/UDP bigbox3.site3.atlanta.com;branch=z9hG4bK77ef4c2312983.1

;received=192.0.2.2

Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8

;received=192.0.2.1

To: Bob <sip:bob@biloxi.com>;tag=a6c85cf

From: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

CSeq: 314159 INVITE

Contact: <sip:bob@192.0.2.4>

Content-Type: application/sdp

Content-Length: 131

(Bob’s SDP not shown)

F11 200 OK atlanta.com proxy -> Alice

SIP/2.0 200 OK

Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds8

;received=192.0.2.1

To: Bob <sip:bob@biloxi.com>;tag=a6c85cf

From: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

CSeq: 314159 INVITE

Contact: <sip:bob@192.0.2.4>

Content-Type: application/sdp

Content-Length: 131

(Bob’s SDP not shown)

F12 ACK Alice -> Bob

ACK sip:bob@192.0.2.4 SIP/2.0

Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKnashds9

Max-Forwards: 70

To: Bob <sip:bob@biloxi.com>;tag=a6c85cf

From: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

CSeq: 314159 ACK

Content-Length: 0

在Alice和Bob之间的媒体会话现在建立了。Bob首先挂机。注意Bob的SIP电话维持它自己的Cseq号码空间，在这里，是231开始的。由于Bob发起请求，那么To和From URI和tags交换了。

F13 BYE Bob -> Alice

BYE sip:alice@pc33.atlanta.com SIP/2.0

Via: SIP/2.0/UDP 192.0.2.4;branch=z9hG4bKnashds10

Max-Forwards: 70

From: Bob <sip:bob@biloxi.com>;tag=a6c85cf

To: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

CSeq: 231 BYE

Content-Length: 0

F14 200 OK Alice -> Bob

SIP/2.0 200 OK

Via: SIP/2.0/UDP 192.0.2.4;branch=z9hG4bKnashds10

From: Bob <sip:bob@biloxi.com>;tag=a6c85cf

To: Alice <sip:alice@atlanta.com>;tag=1928301774

Call-ID: a84b4c76e66710

CSeq: 231 BYE

Content-Length: 0