|
356 |
SIP: Understanding the Session Initiation Protocol |
M11 |
REL CauseCode=16 Normal Clearing |
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M12 |
SIP/2.0 200 OK |
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Via: SIP/2.0/UDP 8.19.19.06:5060;branch=z9hG4bK321 |
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From: <sip:filo.farnsworth@television.tv>;tag=12 |
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To: <sip:+12025551313@gw.carrier.com;user=phone>;tag=37 |
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Call-ID: 49235243082018498 |
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CSeq: 3 BYE |
M13 |
RLC |
|
16.4 PSTN to SIP Call Through a Gateway
Figure 16.4 shows a call originating from a telephone in the PSTN that terminates on a SIP phone in the Internet. The compact form of SIP is used throughout the example. Note that there is no compact form for CSeq or Max-Forwards.
M1 Setup |
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CdPN=6512345, NPI=E.164 |
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Dialed telephone number |
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NOA=International |
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CgPN=4567890, NPI=E.164, |
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PSTN caller’s number |
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NOA=International |
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Figure 16.4 PSTN to SIP call flow through a gateway.
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Call Flow Examples |
357 |
M2 |
INVITE sip:+6512345@incoming.com;user=phone SIP/2.0 |
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v: SIP/2.0/UDP 65.3.4.1:5060;branch=z9hG4bK343 |
Compact form of |
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Max-Forwards: 70 |
headers includes tag |
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f: <sip:+45.67890@incoming.com;user=phone>;tag=6a589b1 |
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t: <sip:+65.12345@incoming.com;user=phone> |
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i: a3-65-99-1d |
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CSeq: 1 INVITE |
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m: 65.3.4.1 |
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c: application/sdp |
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l: 126 |
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v=0 |
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o=- 2890844535 2890844535 IN IP4 65.3.4.1 |
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s=- |
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t=0 0 |
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c=IN IP4 65.3.4.1 |
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m=audio 62432 RTP/AVP 0 |
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a=rtpmap:0 PCMU/8000 |
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M3 |
SIP/2.0 100 Trying |
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v: SIP/2.0/UDP 65.3.4.1:5060;branch=z9hG4bK343 |
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f: <sip:+45.67890@incoming.com;user=phone>;tag=6a589b1 |
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t: sip:+65.12345@incoming.com;user=phone |
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i: a3-65-99-1d |
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CSeq: 1 INVITE |
|
M4 |
Service Query: +65-12345 |
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M5 |
Location Service Response: |
Number maps to SIP URI |
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sip:user@home.com |
|
M6 |
INVITE sip:user@home.com SIP/2.0 |
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v: SIP/2.0/UDP 176.5.8.2:5060;branch=z9hG4bK942834822.1 |
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v: SIP/2.0/UDP 65.3.4.1:5060;branch=z9hG4bK343 |
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Max-Forwards: 69 |
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f: <sip:+45.67890@incoming.com;user=phone>;tag=6a589b1 |
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t: sip:+65.12345@incoming.com;user=phone |
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i: a3-65-99-1d |
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CSeq: 1 INVITE |
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m: 65.3.4.1 |
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c: application/sdp |
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l: 126 |
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v=0 |
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o=- 2890844535 2890844535 IN IP4 65.3.4.1 |
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s=- |
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t=0 0 |
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c=IN IP4 65.3.4.1 |
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m=audio 62432 RTP/AVP 0 |
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a=rtpmap:0 PCMU/8000 |
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M7 |
SIP/2.0 180 Ringing |
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v: SIP/2.0/UDP 176.5.8.2:5060;branch=z9hG4bK942834822.1 |
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v: SIP/2.0/UDP 65.3.4.1:5060;branch=z9hG4bK343 |
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f: <sip:+45.67890@incoming.com;user=phone>;tag=6a589b1 |
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t: <sip:+65.12345@incoming.com;user=phone>;tag=8657 |
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i: a3-65-99-1d |
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m: sip:user@client.home.com |
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CSeq: 1 INVITE |
|
|
358 |
SIP: Understanding the Session Initiation Protocol |
M8 |
SIP/2.0 180 Ringing |
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v: SIP/2.0/UDP 65.3.4.1:5060;branch=z9hG4bK343 |
|
|
f: <sip:+45.67890@incoming.com;user=phone>;tag=6a589b1 |
|
|
t: <sip:+65.12345@incoming.com;user=phone>;tag=8657 |
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|
i: a3-65-99-1d |
|
|
CSeq: 1 INVITE |
M9 |
Alerting |
|
M10 |
SIP/2.0 200 OK |
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v: SIP/2.0/UDP 176.5.8.2:5060;branch=z9hG4bK942834822.1 |
|
|
v: SIP/2.0/UDP 65.3.4.1:5060;branch=z9hG4bK343 |
|
|
f: <sip:+45.67890@incoming.com;user=phone>;tag=6a589b1 |
|
|
t: <sip:+65.12345@incoming.com;user=phone>;tag=8657 |
|
|
i: a3-65-99-1d |
|
|
CSeq: 1 INVITE |
|
|
m: sip:user@client.home.com |
|
|
c: application/sdp |
|
|
l: 125 |
|
|
v=0 |
|
|
o=- 2890844565 2890844565 IN IP4 7.8.9.10 |
|
|
s=- |
|
|
t=0 0 |
|
|
c=IN IP4 7.8.9.10 |
|
|
m=audio 5004 RTP/AVP 0 |
|
|
a=rtpmap:0 PCMU/8000 |
M11 |
SIP/2.0 200 OK |
|
|
|
v: SIP/2.0/UDP 65.3.4.1:5060;branch=z9hG4bK343 |
|
|
f: <sip:+45.67890@incoming.com;user=phone>;tag=6a589b1 |
|
|
t: <sip:+65.12345@incoming.com;user=phone>;tag=8657 |
|
|
i: a3-65-99-1d |
|
|
CSeq: 1 INVITE |
|
|
M: sip:user@home.com |
|
|
c: application/sdp |
|
|
l: 125 |
|
|
v=0 |
|
|
o=- 2890844565 2890844565 IN IP4 7.8.9.10 |
|
|
s=- |
|
|
t=0 0 |
|
|
c=IN IP4 7.8.9.10 |
|
|
m=audio 5004 RTP/AVP 0 |
|
|
a=rtpmap:0 PCMU/8000 |
M12 |
Connect |
|
M13 |
ACK sip:user@home.com SIP/2.0 |
|
|
|
v: SIP/2.0/UDP 65.3.4.1:5060;branch=z9hG4bK453 |
|
|
Max-Forwards: 70 |
|
|
f: <sip+45.67890@incoming.com;user=phone>;tag=6a589b1 |
|
|
t: <sip+65.12345@incoming.com;user=phone>;tag=8657 |
|
|
i: a3-65-99-1d |
|
|
CSeq: 1 ACK |
Call Flow Examples |
359 |
16.5 Parallel Search
In this example the caller receives multiple possible locations for the called party from a redirect server. Instead of trying the locations one at a time, the UA implements a parallel search for the called party by simultaneously sending the INVITE to three different locations, as shown in Figure 16.5. The SIP specification gives an example of this behavior in a proxy server, which is called a forking proxy.
In this example the first location responds with a 404 Not Found response. The second location responds with a 180 Ringing response, while the third location returns a 180 Ringing then a 200 OK response. The caller then sends an ACK to the third location to establish the call. Because one successful response has been received, a CANCEL is sent to the second location to terminate the search.
Figure 16.5 Parallel search example call flow.
360 |
SIP: Understanding the Session Initiation Protocol |
The second location sends a 200 OK to the CANCEL and a 487 Request Terminated to the INVITE. This example shows some customized reason phrases in messages M7, M10, and M11. This example also shows a Call-ID with an IP address which is not recommended.
M1 |
INVITE sip:faraday@effect.org SIP/2.0 |
|
|
Via: SIP/2.0/UDP kings.cambridge.edu.uk:60000;branch=z9hG4bK3 Port |
|
|
;received=7.9.18.12 |
60000 is used |
|
Max-Forwards: 70 |
|
|
From: J.C. Maxwell <sip:james.maxwell@kings.cambridge.edu.uk>; |
|
|
tag=4 |
|
|
To: <sip:faraday@effect.org> |
|
|
Call-ID: mNjdwWjkBfWrd@7.9.18.12 |
CSeq initialized to 54 |
|
CSeq: 54 INVITE |
|
|
Contact:<sip:james.maxwell@kings.cambridge.edu.uk> |
|
|
Content-Type: application/sdp |
|
|
Content-Length: 129 |
|
|
v=0 |
|
|
o=max 2890844521 2890844521 IN IP4 7.9.18.12 |
|
|
s=- |
|
|
t=0 0 |
|
|
c=IN IP4 7.9.18.12 |
|
|
m=audio 32166 RTP/AVP 96 |
|
|
a=rtpmap:96 iLBC/8000 |
|
M2 |
SIP/2.0 300 Multiple locations |
Redirect server returns three locations |
|
Via: SIP/2.0/UDP kings.cambridge.edu.uk:60000;branch=z9hG4bK3 |
|
|
;received=7.9.18.12 |
|
|
From: J.C. Maxwell <sip:james.maxwell@kings.cambridge.edu.uk> |
|
|
;tag=4 |
|
|
To:<sip:faraday@effect.org>;tag=1024 |
|
|
Call-ID: mNjdwWjkBfWrd@7.9.18.12 |
|
|
CSeq: 54 INVITE |
|
|
Contact: <sip:faraday@lab.royalsoc.gb> |
|
|
Contact: <sip:+44.555.1212@sip-phone.effect.org;user=phone> |
|
|
Contact: <sip:michael.faraday@commonroom.club.gb> |
|
M3 |
ACK sip:faraday@effect.org |
|
|
Via: SIP/2.0/UDP kings.cambridge.edu.uk:60000;branch=z9hG4bK3 |
|
|
Max-Forwards: 70 |
|
|
From: J.C. Maxwell <sip:james.maxwell@kings.cambridge.edu.uk> |
|
|
;tag=4 |
|
|
To: <sip:faraday@effect.org>;tag=1024 |
|
|
Call-ID: mNjdwWjkBfWrd@7.9.18.12 |
|
|
CSeq: 54 INVITE |
|
M4 |
INVITE sip:faraday@lab.royalsoc.gb SIP/2.0 |
|
|
Via: SIP/2.0/UDP kings.cambridge.edu.uk:60000;branch=z9hG4bK1 |
|
|
Max-Forwards: 70 |
|
|
From: J.C. Maxwell <sip:james.maxwell@kings.cambridge.edu.uk> |
|
|
;tag=5 |
Tag is not copied |
|
To: <sip:faraday@effect.org> |
|
|
Call-ID: mNjdwWjkBfWrd@7.9.18.12 |
Call-ID unchanged |
|
CSeq: 55 INVITE |
CSeq incremented |
Contact: <sip:james.maxwell@kings.cambridge.edu.uk>
Content-Type: application/sdp
Call Flow Examples |
361 |
Content-Length: 129
v=0
o=max 2890844521 2890844521 IN IP4 7.9.18.12 s=-
t=0 0
c=IN IP4 7.9.18.12 m=audio 32166 RTP/AVP 96 a=rtpmap:96 iLBC/8000
M5 INVITE sip:+44.555.1212@sip-phone.effect.org;user=phone SIP/2.0 Via: SIP/2.0/UDP kings.cambridge.edu.uk:60000;branch=z9hG4bK2 Max-Forwards: 70
From: J.C. Maxwell <sip:james.maxwell@kings.cambridge.edu.uk> ;tag=5
To: <sip:faraday@effect.org> Call-ID: mNjdwWjkBfWrd@7.9.18.12 CSeq: 55 INVITE
Contact: <sip:james.maxwell@kings.cambridge.edu.uk> Content-Type: application/sdp
Content-Length: 129
v=0
o=max 2890844521 2890844521 IN IP4 7.9.18.12 s=-
t=0 0
c=IN IP4 7.9.18.12 m=audio 32166 RTP/AVP 96 a=rtpmap:96 iLBC/8000
M6 INVITE sip:faraday@commonroom.club.gb SIP/2.0
Via: SIP/2.0/UDP kings.cambridge.edu.uk:60000;branch=z9hG4bK3 Max-Forwards: 70
From: J.C. Maxwell <sip:james.maxwell@kings.cambridge.edu.uk> ;tag=5
To: <sip:faraday@effect.org> Call-ID: mNjdwWjkBfWrd@7.9.18.12 CSeq: 55 INVITE
Contact: <sip:james.maxwell@kings.cambridge.edu.uk> Content-Type: application/sdp
Content-Length: 129
v=0
o=max 2890844521 2890844521 IN IP4 7.9.18.12 s=-
t=0 0
c=IN IP4 7.9.18.12 m=audio 32166 RTP/AVP 96 a=rtpmap:96 iLBC/8000
M7 SIP/2.0 404 The member you have requested is not available Via: SIP/2.0/UDP kings.cambridge.edu.uk:60000;branch=z9hG4bK1 ;received=7.9.18.12
From: J.C. Maxwell <sip:james.maxwell@kings.cambridge.edu.uk> ;tag=5
To: <sip:faraday@effect.org>;tag=f6 Call-ID: mNjdwWjkBfWrd@7.9.18.12 CSeq: 55 INVITE
|
362 |
SIP: Understanding the Session Initiation Protocol |
M8 |
ACK sip:faraday@lab.royalsoc.gb SIP/2.0 |
|
|
|
Via: SIP/2.0/UDP kings.cambridge.edu.uk:60000z9hG4bK1 |
|
|
Max-Forwards: 70 |
|
|
From: J.C. Maxwell <sip:james.maxwell@kings.cambridge.edu.uk> |
|
|
;tag=5 |
|
|
To: <sip:faraday@effect.org>;tag=f6 |
|
|
Call-ID: mNjdwWjkBfWrd@7.9.18.12 |
|
|
CSeq: 55 ACK |
M9 |
SIP/2.0 180 Ringing |
|
|
|
Via: SIP/2.0/UDP kings.cambridge.edu.uk:60000;branch=z9hG4bK2 |
|
|
;received=7.9.18.12 |
|
|
From: J.C. Maxwell <sip:james.maxwell@kings.cambridge.edu.uk> |
|
|
;tag=5 |
|
|
To: <sip:faraday@effect.org>;tag=6321 |
|
|
Call-ID: mNjdwWjkBfWrd@7.9.18.12 |
|
|
Contact: <sip:+44.555.1212@sip-phone.effect.org> |
|
|
CSeq: 55 INVITE |
M10 |
SIP/2.0 180 Please wait while we locate Mr. Faraday |
|
|
|
Via: SIP/2.0/UDP kings.cambridge.edu.uk:60000;branch=z9hG4bK3 |
|
|
;received=7.9.18.12 |
|
|
From: J.C. Maxwell <sip:james.maxwell@kings.cambridge.edu.uk> |
|
|
;tag=5 |
|
|
To: <sip:faraday@effect.org>;tag=531 |
|
|
Call-ID: mNjdwWjkBfWrd@7.9.18.12 |
|
|
Contact: <sip:faraday@commonroom.club.gb> |
|
|
CSeq: 55 INVITE |
M11 |
SIP/2.0 200 Mr. Faraday at your service? |
|
|
|
Via: SIP/2.0/UDP kings.cambridge.edu.uk:60000;branch=z9hG4bK3 |
|
|
;received=7.9.18.12 |
|
|
From: J.C. Maxwell <sip:james.maxwell@kings.cambridge.edu.uk> |
|
|
;tag=5 |
|
|
To: <sip:faraday@effect.org>;tag=531 |
|
|
Call-ID: mNjdwWjkBfWrd@7.9.18.12 |
|
|
CSeq: 55 INVITE |
|
|
User-Agent: PDV/v4 |
|
|
Contact: <sip:faraday@commonroom.club.gb> |
|
|
Content-Type: application/sdp |
|
|
Content-Length: 131 |
|
|
v=0 |
|
|
o=max 2890844521 2890844521 IN IP4 6.22.17.89 |
|
|
t=0 0 |
|
|
c=IN IP4 6.22.17.89 |
|
|
m=audio 43782 RTP/AVP 4 |
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a=rtpmap:4 DVI/8000 |
M12 |
ACK sip:faraday@commonroom.club.gb;user=ip SIP/2.0 |
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Via: SIP/2.0/UDP kings.cambridge.edu.uk:60000;branch=z9hG4bK3 |
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Max-Forwards: 70 |
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From: J.C. Maxwell <sip:james.maxwell@kings.cambridge.edu.uk> |
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;tag=5 |
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To: <sip:faraday@effect.org>;tag=531 |
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Call-ID: mNjdwWjkBfWrd@7.9.18.12 |
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CSeq: 55 ACK |
M13 CANCEL sip:+44.555.1212@sip-phone.effect.org;user=phone SIP/2.0