SIP消息由3部分组成，分别为启动行，消息头，消息体，每行后都由回车换行符号CRLF或由CR、LF其中之一组成。消息头后填充空行CRLF。格式如下：
generic-message = start-line（Request-Line / Status-Line）
*message-header
CRLF
[ message-body ]
1、请求行
请求行包括3部分，方法，请求URI,SIP版本，结束符号可以为CRLF、CR、LF，空格可以被忽略，请求行格式如下SP为single space.
Request-Line = Method SP Request-URI SP SIP-Version CRLF
例子：INVITE sip:555@192.168.83.165 SIP/2.0
方法：RFC3261规格*定义了6种方法，REGISTER、INVITE、ACK、CANCEL、BYE、OPTIONS.
REGISTER：注册联系人信息到代理服务器。
OPTIONS:查询服务器的能力，支持哪些选项。
请求URI：正在发送请求并被处理的用户信息或服务，不能包含空格不能包含在<>之内。
SIP版本：SIP版本是大小写敏感的，必须为大写，但实际使用中如果小写也没什么差异。
2、响应
响应行包括3部分，SIP版本，状态码，过程阶段，结束符号可以为CRLF、CR、LF，空格可以被忽略，格式如下：
Status-Line = SIP-Version SP Status-Code SP Reason-Phrase CRLF
例子：SIP/2.0 100 Trying
状态码给机器翻译使用，Reason-Phrase给用户查看使用，状态码范围如下，第一个数字为类别代表，共3个数字。
1xx: Provisional -- request received, continuing to process the
request;
2xx: Success -- the action was successfully received, understood,
and accepted;
3xx: Redirection -- further action needs to be taken in order to
complete the request;
4xx: Client Error -- the request contains bad syntax or cannot be
fulfilled at this server;
5xx: Server Error -- the server failed to fulfill an apparently
valid request;
6xx: Global Failure -- the request cannot be fulfilled at any
server.
3、头域格式（Header Field Format）
field-name: field-value
实例：Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-fe184d2d9922c37b-1--d87543-;rport
冒号左域可以有空格举例如下：
Subject: lunch
Subject : lunch
Subject :lunch
Subject: lunch
头域值可以为多行，在每行前面至少有一个空格或Tab，下面两张表达是相等的。
Subject: I know you're there, pick up the phone and talk to me!
Subject: I know you're there,
pick up the phone
and talk to me!
下面的2种方式有的相等，有的不相等,不相等的原因主要是顺序不同。
The following groups of header field rows are valid and equivalent:
Route: <sip:alice@atlanta.com>
Subject: Lunch
Route: <sip:bob@biloxi.com>
Route: <sip:carol@chicago.com>
Route: <sip:alice@atlanta.com>, <sip:bob@biloxi.com>
Route: <sip:carol@chicago.com>
Subject: Lunch
Subject: Lunch
Route: <sip:alice@atlanta.com>, <sip:bob@biloxi.com>,
<sip:carol@chicago.com>
Each of the following blocks is valid but not equivalent to the
others:
Route: <sip:alice@atlanta.com>
Route: <sip:bob@biloxi.com>
Route: <sip:carol@chicago.com>
Route: <sip:bob@biloxi.com>
Route: <sip:alice@atlanta.com>
Route: <sip:carol@chicago.com>
Route: <sip:alice@atlanta.com>,<sip:carol@chicago.com>,
<sip:bob@biloxi.com>
大小写敏感问题：对于域名，域值 参数名和参数值都不区分大小写，但对于值所引用的字符串是区分大小的。
field-name: field-value *(;parameter-name=parameter-value)
Contact: <sip:alice@atlanta.com>;expires=3600
is equivalent to
CONTACT: <sip:alice@atlanta.com>;ExPiReS=3600
and
Content-Disposition: session;handling=optional
is equivalent to
content-disposition: Session;HANDLING=OPTIONAL
The following two header fields are not equivalent:
Warning: 370 devnull "Choose a bigger pipe"
Warning: 370 devnull "CHOOSE A BIGGER PIPE"
4、请求头域和响应头域是不同的，如果请求头域在响应中则直接被忽略，具体可参考RFC3261。
where 中R为请求，r为响应
Example:
Header field where proxy ACK BYE CAN INV OPT REG
___________________________________________________________
Accept R - o - o m* o
Accept 2xx - - - o m* o
Accept 415 - c - c c c
Accept-Encoding R - o - o o o
Accept-Encoding 2xx - - - o m* o
Accept-Encoding 415 - c - c c c
Accept-Language R - o - o o o
Accept-Language 2xx - - - o m* o
Accept-Language 415 - c - c c c
Alert-Info R ar - - - o - -
Alert-Info 180 ar - - - o - -
Allow R - o - o o o
Allow 2xx - o - m* m* o
Allow r - o - o o o
Allow 405 - m - m m m
Authentication-Info 2xx - o - o o o
Authorization R o o o o o o
Call-ID c r m m m m m m
Call-Info ar - - - o o o
Contact R o - - m o o
Contact 1xx - - - o - -
Contact 2xx - - - m o o
Contact 3xx d - o - o o o
Contact 485 - o - o o o
Content-Disposition o o - o o o
Content-Encoding o o - o o o
Content-Language o o - o o o
Content-Length ar t t t t t t
Content-Type * * - * * *
CSeq c r m m m m m m
Date a o o o o o o
Error-Info 300-699 a - o o o o o
Expires - - - o - o
From c r m m m m m m
In-Reply-To R - - - o - -
Max-Forwards R amr m m m m m m
Min-Expires 423 - - - - - m
MIME-Version o o - o o o
Organization ar - - - o o o
Table 2: Summary of header fields, A--O
Header field where proxy ACK BYE CAN INV OPT REG
___________________________________________________________________
Priority R ar - - - o - -
Proxy-Authenticate 407 ar - m - m m m
Proxy-Authenticate 401 ar - o o o o o
Proxy-Authorization R dr o o - o o o
Proxy-Require R ar - o - o o o
Record-Route R ar o o o o o -
Record-Route 2xx,18x mr - o o o o -
Reply-To - - - o - -
Require ar - c - c c c
Retry-After 404,413,480,486 - o o o o o
500,503 - o o o o o
600,603 - o o o o o
Route R adr c c c c c c
Server r - o o o o o
Subject R - - - o - -
Supported R - o o m* o o
Supported 2xx - o o m* m* o
Timestamp o o o o o o
To c(1) r m m m m m m
Unsupported 420 - m - m m m
User-Agent o o o o o o
Via R amr m m m m m m
Via rc dr m m m m m m
Warning r - o o o o o
WWW-Authenticate 401 ar - m - m m m
WWW-Authenticate 407 ar - o - o o o
Table 3: Summary of header fields, P--Z; (1): copied with possible
addition of tag
Accept: application/sdp;level=1, application/x-private, text/html
5、头域可以为精简格式，当报文大于MTU时，可能会出现此类情况。
Content-Type精简为c
Content-Type: application/sdp
c: text/html; charset=ISO-8859-4
The compact form of the Call-ID header field is i.
Examples:
Call-ID: f81d4fae-7dec-11d0-a765-00a0c91e6bf6@biloxi.com
i:f81d4fae-7dec-11d0-a765-00a0c91e6bf6@192.0.2.4
6、请求和响应都可能包含Body，消息体内容和含义由请求和回应方法决定。
INVITE sip:555@192.168.83.165 SIP/2.0
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-fe184d2d9922c37b-1--d87543-;rport
Max-Forwards: 70
Contact: <sip:1111@192.168.83.166:59888>
To: "555"<sip:555@192.168.83.165>
From: "1111"<sip:1111@192.168.83.165>;tag=c84a0f35
Call-ID: Y2M1ZWQzNjZkZGUyNGZjMDQ3ODViNDQxMWNlYjJkMjg.
CSeq: 2 INVITE
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO
Content-Type: application/sdp
Proxy-Authorization: Digest username="1111",realm="192.168.83.165",nonce="f9f1f5c1204f40b398e492c655db4688",uri="sip:555@192.168.83.165",response="915d59413c734aab76a478152abec187",algorithm=MD5
User-Agent: X-Lite release 1011a stamp 39982
Content-Length: 861
v=0
o=- 0 2 IN IP4 192.168.83.166
s=CounterPath X-Lite 3.0
c=IN IP4 192.168.83.166
t=0 0
m=audio 49500 RTP/AVP 107 119 100 106 0 105 98 8 101
a=alt:1 3 : ECRvm16m v+fqLshj 192.168.83.166 49500
a=alt:2 2 : EdbNYVHv KIQdEfz6 192.168.245.1 49500
a=alt:3 1 : yDH1BrYb WlB139Ar 192.168.204.1 49500
a=fmtp:101 0-15
a=rtpmap:107 BV32/16000
a=rtpmap:119 BV32-FEC/16000
a=rtpmap:100 SPEEX/16000
a=rtpmap:106 SPEEX-FEC/16000
a=rtpmap:105 SPEEX-FEC/8000
a=rtpmap:98 iLBC/8000
a=rtpmap:101 telephone-event/8000
a=sendrecv
m=video 21544 RTP/AVP 115 34
a=alt:1 3 : Hc0rAXD9 /SSqAFC7 192.168.83.166 21544
a=alt:2 2 : jJ7atS9D +F6f93kw 192.168.245.1 21544
a=alt:3 1 : A1p82jJp 83lgK3Kn 192.168.204.1 21544
a=fmtp:115 QCIF=1 CIF=1 I=1 J=1 K=1 MaxBR=1960
a=fmtp:34 QCIF=1 CIF=1 MaxBR=1960
a=rtpmap:115 H263-1998/90000
a=rtpmap:34 H263/90000
a=sendrecv
7、消息体内容类型可以为压缩格式，可以为Mime格式，可以为TextUTF-8格式。
Examples:
Content-Type: application/sdp
Content-Type: text/html; charset=ISO-8859-4
8、消息体内容长度为一个整形值，不会出现http chunk的情况。
Content-Length: 861
9、SIP消息，通过消息体长度获取整个消息，SIP可以采用UDP协议，此消息中协商的传输层端口是有限制的，建议tcp、udp使用5060，TLS over TCP使用5061
实际报文交互过程：
REGISTER sip:192.168.83.165 SIP/2.0
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-d724e90eb209ee27-1--d87543-;rport
Max-Forwards: 70
Contact: <sip:1111@192.168.83.166:59888;rinstance=c5ea7f72275f318f>
To: "1111"<sip:1111@192.168.83.165>
From: "1111"<sip:1111@192.168.83.165>;tag=c5368845
Call-ID: MWJlMGU0MWMxZTZlY2ExMWUzOWM4ZGU3ZGFmYTg4YWQ.
CSeq: 1 REGISTER
Expires: 3600
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO
User-Agent: X-Lite release 1011a stamp 39982
Content-Length: 0
SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-d724e90eb209ee27-1--d87543-;rport
CSeq: 1 REGISTER
From: "1111" <sip:1111@192.168.83.165>;tag=c5368845
To: "1111" <sip:1111@192.168.83.165>
WWW-Authenticate: digest realm="192.168.83.165",nonce="8f19b3b571d04476a8f9eb7dbcf3f236"
Call-ID: MWJlMGU0MWMxZTZlY2ExMWUzOWM4ZGU3ZGFmYTg4YWQ.
Server: SIP Server 2008 v3.6.6.773
Content-Length: 0
REGISTER sip:192.168.83.165 SIP/2.0
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-3f489b70543a3713-1--d87543-;rport
Max-Forwards: 70
Contact: <sip:1111@192.168.83.166:59888;rinstance=c5ea7f72275f318f>
To: "1111"<sip:1111@192.168.83.165>
From: "1111"<sip:1111@192.168.83.165>;tag=c5368845
Call-ID: MWJlMGU0MWMxZTZlY2ExMWUzOWM4ZGU3ZGFmYTg4YWQ.
CSeq: 2 REGISTER
Expires: 3600
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO
User-Agent: X-Lite release 1011a stamp 39982
Authorization: Digest username="1111",realm="192.168.83.165",nonce="8f19b3b571d04476a8f9eb7dbcf3f236",uri="sip:192.168.83.165",response="dac398335510f0a2455f71e110448320",algorithm=MD5
Content-Length: 0
SIP/2.0 200 OK
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-3f489b70543a3713-1--d87543-;rport
Contact: <sip:1111@192.168.83.166:59888;rinstance=c5ea7f72275f318f>
CSeq: 2 REGISTER
From: "1111" <sip:1111@192.168.83.165>;tag=c5368845
To: "1111" <sip:1111@192.168.83.165>
Call-ID: MWJlMGU0MWMxZTZlY2ExMWUzOWM4ZGU3ZGFmYTg4YWQ.
Server: SIP Server 2008 v3.6.6.773
Date: Tue, 23 Jul 2013 18:35:06 GMT
Expires: 3600
Content-Length: 0
SUBSCRIBE sip:1111@192.168.83.165 SIP/2.0
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-a7096b57bf12d957-1--d87543-;rport
Max-Forwards: 70
Contact: <sip:1111@192.168.83.166:59888>
To: "1111"<sip:1111@192.168.83.165>
From: "1111"<sip:1111@192.168.83.165>;tag=3f423f36
Call-ID: ZWE1NDI3NTE4MTA3YWFmYTNlODg3YTEwNTc1OWZkOGE.
CSeq: 1 SUBSCRIBE
Expires: 300
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO
User-Agent: X-Lite release 1011a stamp 39982
Event: message-summary
Content-Length: 0
SIP/2.0 489 Event Package Not Supported
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-a7096b57bf12d957-1--d87543-;rport
CSeq: 1 SUBSCRIBE
From: "1111" <sip:1111@192.168.83.165>;tag=3f423f36
To: "1111" <sip:1111@192.168.83.165>
Call-ID: ZWE1NDI3NTE4MTA3YWFmYTNlODg3YTEwNTc1OWZkOGE.
Server: SIP Server 2008 v3.6.6.773
Content-Length: 0
INVITE sip:555@192.168.83.165 SIP/2.0
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-835f7e2a82156907-1--d87543-;rport
Max-Forwards: 70
Contact: <sip:1111@192.168.83.166:59888>
To: "555"<sip:555@192.168.83.165>
From: "1111"<sip:1111@192.168.83.165>;tag=c84a0f35
Call-ID: Y2M1ZWQzNjZkZGUyNGZjMDQ3ODViNDQxMWNlYjJkMjg.
CSeq: 1 INVITE
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO
Content-Type: application/sdp
User-Agent: X-Lite release 1011a stamp 39982
Content-Length: 861
v=0
o=- 0 2 IN IP4 192.168.83.166
s=CounterPath X-Lite 3.0
c=IN IP4 192.168.83.166
t=0 0
m=audio 49500 RTP/AVP 107 119 100 106 0 105 98 8 101
a=alt:1 3 : ECRvm16m v+fqLshj 192.168.83.166 49500
a=alt:2 2 : EdbNYVHv KIQdEfz6 192.168.245.1 49500
a=alt:3 1 : yDH1BrYb WlB139Ar 192.168.204.1 49500
a=fmtp:101 0-15
a=rtpmap:107 BV32/16000
a=rtpmap:119 BV32-FEC/16000
a=rtpmap:100 SPEEX/16000
a=rtpmap:106 SPEEX-FEC/16000
a=rtpmap:105 SPEEX-FEC/8000
a=rtpmap:98 iLBC/8000
a=rtpmap:101 telephone-event/8000
a=sendrecv
m=video 21544 RTP/AVP 115 34
a=alt:1 3 : Hc0rAXD9 /SSqAFC7 192.168.83.166 21544
a=alt:2 2 : jJ7atS9D +F6f93kw 192.168.245.1 21544
a=alt:3 1 : A1p82jJp 83lgK3Kn 192.168.204.1 21544
a=fmtp:115 QCIF=1 CIF=1 I=1 J=1 K=1 MaxBR=1960
a=fmtp:34 QCIF=1 CIF=1 MaxBR=1960
a=rtpmap:115 H263-1998/90000
a=rtpmap:34 H263/90000
a=sendrecv
SIP/2.0 407 Proxy Authentication Required
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-835f7e2a82156907-1--d87543-;rport
CSeq: 1 INVITE
From: "1111" <sip:1111@192.168.83.165>;tag=c84a0f35
To: "555" <sip:555@192.168.83.165>
Proxy-Authenticate: digest realm="192.168.83.165",nonce="f9f1f5c1204f40b398e492c655db4688"
Call-ID: Y2M1ZWQzNjZkZGUyNGZjMDQ3ODViNDQxMWNlYjJkMjg.
Server: SIP Server 2008 v3.6.6.773
Content-Length: 0
ACK sip:555@192.168.83.165 SIP/2.0
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-835f7e2a82156907-1--d87543-;rport
To: "555" <sip:555@192.168.83.165>
From: "1111"<sip:1111@192.168.83.165>;tag=c84a0f35
Call-ID: Y2M1ZWQzNjZkZGUyNGZjMDQ3ODViNDQxMWNlYjJkMjg.
CSeq: 1 ACK
Content-Length: 0
INVITE sip:555@192.168.83.165 SIP/2.0
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-fe184d2d9922c37b-1--d87543-;rport
Max-Forwards: 70
Contact: <sip:1111@192.168.83.166:59888>
To: "555"<sip:555@192.168.83.165>
From: "1111"<sip:1111@192.168.83.165>;tag=c84a0f35
Call-ID: Y2M1ZWQzNjZkZGUyNGZjMDQ3ODViNDQxMWNlYjJkMjg.
CSeq: 2 INVITE
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO
Content-Type: application/sdp
Proxy-Authorization: Digest username="1111",realm="192.168.83.165",nonce="f9f1f5c1204f40b398e492c655db4688",uri="sip:555@192.168.83.165",response="915d59413c734aab76a478152abec187",algorithm=MD5
User-Agent: X-Lite release 1011a stamp 39982
Content-Length: 861
v=0
o=- 0 2 IN IP4 192.168.83.166
s=CounterPath X-Lite 3.0
c=IN IP4 192.168.83.166
t=0 0
m=audio 49500 RTP/AVP 107 119 100 106 0 105 98 8 101
a=alt:1 3 : ECRvm16m v+fqLshj 192.168.83.166 49500
a=alt:2 2 : EdbNYVHv KIQdEfz6 192.168.245.1 49500
a=alt:3 1 : yDH1BrYb WlB139Ar 192.168.204.1 49500
a=fmtp:101 0-15
a=rtpmap:107 BV32/16000
a=rtpmap:119 BV32-FEC/16000
a=rtpmap:100 SPEEX/16000
a=rtpmap:106 SPEEX-FEC/16000
a=rtpmap:105 SPEEX-FEC/8000
a=rtpmap:98 iLBC/8000
a=rtpmap:101 telephone-event/8000
a=sendrecv
m=video 21544 RTP/AVP 115 34
a=alt:1 3 : Hc0rAXD9 /SSqAFC7 192.168.83.166 21544
a=alt:2 2 : jJ7atS9D +F6f93kw 192.168.245.1 21544
a=alt:3 1 : A1p82jJp 83lgK3Kn 192.168.204.1 21544
a=fmtp:115 QCIF=1 CIF=1 I=1 J=1 K=1 MaxBR=1960
a=fmtp:34 QCIF=1 CIF=1 MaxBR=1960
a=rtpmap:115 H263-1998/90000
a=rtpmap:34 H263/90000
a=sendrecv
SIP/2.0 100 Trying
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-fe184d2d9922c37b-1--d87543-;rport
CSeq: 2 INVITE
From: "1111" <sip:1111@192.168.83.165>;tag=c84a0f35
To: "555" <sip:555@192.168.83.165>
Call-ID: Y2M1ZWQzNjZkZGUyNGZjMDQ3ODViNDQxMWNlYjJkMjg.
Server: SIP Server 2008 v3.6.6.773
Content-Length: 0
SIP/2.0 180 Ringing
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-fe184d2d9922c37b-1--d87543-;rport
Contact: <sip:555@192.168.83.167:9874;rinstance=7bfc0f323c22a585>
CSeq: 2 INVITE
From: "1111" <sip:1111@192.168.83.165>;tag=c84a0f35
To: "555" <sip:555@192.168.83.165>;tag=9345b272
Record-Route: <sip:192.168.83.165:5060;lr;transport=UDP;AppDomainId=1>
Call-ID: Y2M1ZWQzNjZkZGUyNGZjMDQ3ODViNDQxMWNlYjJkMjg.
User-Agent: X-Lite release 1011a stamp 39982
Content-Length: 0
SIP/2.0 200 OK
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-fe184d2d9922c37b-1--d87543-;rport
Allow: INVITE,ACK,CANCEL,OPTIONS,BYE,REFER,NOTIFY,MESSAGE,SUBSCRIBE,INFO
Contact: <sip:555@192.168.83.167:9874;rinstance=7bfc0f323c22a585>
CSeq: 2 INVITE
From: "1111" <sip:1111@192.168.83.165>;tag=c84a0f35
To: "555" <sip:555@192.168.83.165>;tag=9345b272
Record-Route: <sip:192.168.83.165:5060;lr;transport=UDP;AppDomainId=1>
Call-ID: Y2M1ZWQzNjZkZGUyNGZjMDQ3ODViNDQxMWNlYjJkMjg.
Content-Type: application/sdp
User-Agent: X-Lite release 1011a stamp 39982
Content-Length: 625
v=0
o=root 7 2 IN IP4 192.168.83.165
s=session
c=IN IP4 192.168.83.165
t=0 0
m=audio 20680 RTP/AVP 107 119 100 106 0 105 98 8 101
a=alt:1 1 : Michael 9kksk 192.168.83.165 20680
a=fmtp:101 0-15
a=rtpmap:107 BV32/16000
a=rtpmap:119 BV32-FEC/16000
a=rtpmap:100 SPEEX/16000
a=rtpmap:106 SPEEX-FEC/16000
a=rtpmap:105 SPEEX-FEC/8000
a=rtpmap:98 iLBC/8000
a=rtpmap:101 telephone-event/8000
a=sendrecv
m=video 20936 RTP/AVP 115 34
a=alt:1 1 : Michael 9kksk 192.168.83.165 20936
a=fmtp:115 QCIF=1 I=1 J=1 K=1 MaxBR=1960
a=fmtp:34 QCIF=1 MaxBR=1960
a=rtpmap:115 H263-1998/90000
a=rtpmap:34 H263/90000
a=sendrecv
ACK sip:555@192.168.83.167:9874;rinstance=7bfc0f323c22a585 SIP/2.0
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-073a2e407b154053-1--d87543-;rport
Max-Forwards: 70
Route: <sip:192.168.83.165:5060;lr;transport=UDP;AppDomainId=1>
Contact: <sip:1111@192.168.83.166:59888>
To: "555"<sip:555@192.168.83.165>;tag=9345b272
From: "1111"<sip:1111@192.168.83.165>;tag=c84a0f35
Call-ID: Y2M1ZWQzNjZkZGUyNGZjMDQ3ODViNDQxMWNlYjJkMjg.
CSeq: 2 ACK
Proxy-Authorization: Digest username="1111",realm="192.168.83.165",nonce="f9f1f5c1204f40b398e492c655db4688",uri="sip:555@192.168.83.165",response="915d59413c734aab76a478152abec187",algorithm=MD5
User-Agent: X-Lite release 1011a stamp 39982
Content-Length: 0
BYE sip:555@192.168.83.167:9874;rinstance=7bfc0f323c22a585 SIP/2.0
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-562b6a3e7f7e2e07-1--d87543-;rport
Max-Forwards: 70
Route: <sip:192.168.83.165:5060;lr;transport=UDP;AppDomainId=1>
Contact: <sip:1111@192.168.83.166:59888>
To: "555"<sip:555@192.168.83.165>;tag=9345b272
From: "1111"<sip:1111@192.168.83.165>;tag=c84a0f35
Call-ID: Y2M1ZWQzNjZkZGUyNGZjMDQ3ODViNDQxMWNlYjJkMjg.
CSeq: 3 BYE
Proxy-Authorization: Digest username="1111",realm="192.168.83.165",nonce="f9f1f5c1204f40b398e492c655db4688",uri="sip:555@192.168.83.167:9874;rinstance=7bfc0f323c22a585",response="7da14453ede7bc0de9483b5fa1f86d14",algorithm=MD5
User-Agent: X-Lite release 1011a stamp 39982
Reason: SIP;description="User Hung Up"
Content-Length: 0
SIP/2.0 200 OK
Via: SIP/2.0/UDP 192.168.83.166:59888;branch=z9hG4bK-d87543-562b6a3e7f7e2e07-1--d87543-;rport
Contact: <sip:555@192.168.83.167:9874;rinstance=7bfc0f323c22a585>
CSeq: 3 BYE
From: "1111" <sip:1111@192.168.83.165>;tag=c84a0f35
To: "555" <sip:555@192.168.83.165>;tag=9345b272
Record-Route: <sip:192.168.83.165:5060;lr;transport=UDP;AppDomainId=1>
Call-ID: Y2M1ZWQzNjZkZGUyNGZjMDQ3ODViNDQxMWNlYjJkMjg.
User-Agent: X-Lite release 1011a stamp 39982
Content-Length: 0