VoLTE Conference
VoLTE conference call is a technology by which more than 2 UE(persons) can communicate each other within the same call. From user's point of view, it is similar to multi-party call in 3G communication. I don't think I need to explain any further on what is VoLTE call since most of users are already had experiences with various type of conference call using IP phones or PC software. You can think of VoLTE conference call as one of those conference call you are already familiar with.
Even though all of these variations are almost same technology at high level view, the detailed implementation and protocol sequences would be different depending on the specification from the solution providers.
Within 3GPP, the framework of VoLTE Conference call is defined in TS 24.147. However, I see a little bit of variations as of now (Jun 2017) depending on network operators. So I will try to introduce various different variations as I experience more of each individual cases.
Case 1 : INVITE from Conference Factory
Conceptually I think this is the simplest way of setting up VoLTE conference, but I haven't seen this cases really being used. Overall procedure is simple as follows :
i) Create a Conference from a conference factory
ii) Invite each participants (users) from the factory
Overall procedure can be illustrated as below.
(3) Registration
REGISTER sip:192.168.1.2 SIP/2.0
Via: SIP/2.0/TCP 192.168.1.2:49494;branch=z9hG4bKdf81eff1bfc9486e9969d1d71e0334fe5dc1b0df;rport;transport=tcp
Max-Forwards: 70
Call-ID: 17c9571913a84b6d92510e2f99d37db7
CSeq: 1 REGISTER
From: <sip:conference1@testnet-conference.com>;tag=0000000012
To: <sip:conference1@testnet-conference.com>
User-Agent: testnet-Conference/3923
Contact: <sip:conference1@192.168.1.2:49494;transport=tcp>
Contact: <sip:conference1@[2001:0:0:1::2]:49495;transport=tcp>
Expires: 3600000
Privacy: none
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=000000000000000
P-Preferred-Identity: <sip:conference1@testnet-conference.com>
Content-Length: 0
Route: <sip:192.168.1.2:5060;lr>
(8) INVITE UA1
To: <sip:UA1@testnet-cscf.com>
From: <sip:conference1@testnet-conference.com>;tag=0000000015
Supported: 100rel
Supported: precondition
User-Agent: testnet-Conference/3923
Content-Type: application/sdp
Allow: INVITE, PRACK, UPDATE, ACK, BYE, CANCEL, MESSAGE, REFER, SUBSCRIBE, NOTIFY
Allow-Events: conference
Referred-By: <sip:conference1@testnet-conference.com>
Content-Length: 569
Route: <sip:192.168.1.2:5060;lr>
Contact: <sip:conference1@192.168.1.2:49494;transport=tcp>;isfocus
v=0
o=testnet 99 96099 IN IP4 192.168.1.2
s=-
i=A VOIP Session
c=IN IP4 192.168.1.2
t=0 0
m=audio 60000 RTP/AVP 107 97 8 0 101
b=AS:64
b=RS:800
b=RR:2400
a=ptime:20
a=maxptime:20
a=rtpmap:107 AMR-WB/16000
a=fmtp:107 octet-align=1; mode-set=2
a=rtpmap:97 AMR/8000
a=fmtp:97 octet-align=1; mode-set=7
a=rtpmap:8 PCMA/8000/1
a=rtpmap:0 PCMU/8000/1
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=mid:0
a=sendrecv
a=rtcp:60001
a=curr:qos local none
a=curr:qos remote none
a=des:qos mandatory local sendrecv
a=des:qos optional remote sendrecv
(9) INVITE UA1
INVITE sip:UA1@192.168.1.1:49259;transport=udp SIP/2.0
Via: SIP/2.0/UDP 192.168.1.2:65203;branch=z9hG4bK5f6774622fed4aa387e5ff64425d677433;rport;transport=udp
Via: SIP/2.0/TCP 192.168.1.2:49494;branch=z9hG4bKdf81eff1bfc9486e9969d1d71e0334fe69f74ce3;transport=tcp;rport=49496
Max-Forwards: 69
Call-ID: 1a953b235f474583a477ea32c5dbaf18
CSeq: 16001 INVITE
To: <sip:UA1@testnet-cscf.com>
From: <sip:conference1@testnet-conference.com>;tag=0000000015
Supported: 100rel
Supported: precondition
User-Agent: testnet-Conference/3923
Content-Type: application/sdp
Allow: INVITE, PRACK, UPDATE, ACK, BYE, CANCEL, MESSAGE, REFER, SUBSCRIBE, NOTIFY
Allow-Events: conference
Referred-By: <sip:conference1@testnet-conference.com>
Content-Length: 569
Contact: <sip:conference1@192.168.1.2:49494;transport=tcp>;isfocus
Record-Route: <sip:192.168.1.2;lr>
v=0
o=testnet 99 96099 IN IP4 192.168.1.2
s=-
i=A VOIP Session
c=IN IP4 192.168.1.2
t=0 0
m=audio 60000 RTP/AVP 107 97 8 0 101
b=AS:64
b=RS:800
b=RR:2400
a=ptime:20
a=maxptime:20
a=rtpmap:107 AMR-WB/16000
a=fmtp:107 octet-align=1; mode-set=2
a=rtpmap:97 AMR/8000
a=fmtp:97 octet-align=1; mode-set=7
a=rtpmap:8 PCMA/8000/1
a=rtpmap:0 PCMU/8000/1
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=mid:0
a=sendrecv
a=rtcp:60001
a=curr:qos local none
a=curr:qos remote none
a=des:qos mandatory local sendrecv
a=des:qos optional remote sendrecv
(10) 200 OK
SIP/2.0 200 OK
Via: SIP/2.0/UDP 192.168.1.2:65203;rport=65203;branch=z9hG4bK5f6774622fed4aa387e5ff64425d677433;transport=udp
From: <sip:conference1@testnet-conference.com>;tag=0000000015
To: <sip:UA1@testnet-cscf.com>;tag=1786367320
Contact: <sip:UA1@192.168.1.1:49259;transport=udp>
Call-ID: 1a953b235f474583a477ea32c5dbaf18
CSeq: 16001 INVITE
Content-Type: application/sdp
Content-Length: 561
Via: SIP/2.0/TCP 192.168.1.2:49494;rport=49496;branch=z9hG4bKdf81eff1bfc9486e9969d1d71e0334fe69f74ce3;transport=tcp
Record-Route: <sip:192.168.1.2;lr>
Allow: ACK, BYE, CANCEL, INVITE, MESSAGE, NOTIFY, OPTIONS, PRACK, REFER, UPDATE
v=0
o=doubango 1983 678901 IN IP4 192.168.1.1
s=-
c=IN IP4 192.168.1.1
t=0 0
m=audio 17522 RTP/AVP 8 0 101
a=ptime:20
a=silenceSupp:off - - - -
a=rtpmap:8 PCMA/8000/1
a=rtpmap:0 PCMU/8000/1
a=rtpmap:101 telephone-event/8000/1
a=fmtp:101 0-16
a=sendrecv
a=ssrc:1397501633 cname:doubango@1340366314
a=ssrc:1397501633 mslabel:6994f7d1-6ce9-4fbd-acfd-84e5131ca2e2
a=ssrc:1397501633 label:doubango@audio
a=curr:qos local none
a=curr:qos remote none
a=des:qos optional local sendrecv
a=des:qos optional remote sendrecv
a=conf:qos remote sendrecv
(11) 200 OK
SIP/2.0 200 OK
From: <sip:conference1@testnet-conference.com>;tag=0000000015
To: <sip:UA1@testnet-cscf.com>;tag=1786367320
Contact: <sip:UA1@192.168.1.1:49259;transport=udp>
Call-ID: 1a953b235f474583a477ea32c5dbaf18
CSeq: 16001 INVITE
Content-Type: application/sdp
Content-Length: 561
Via: SIP/2.0/TCP 192.168.1.2:49494;rport=49496;branch=z9hG4bKdf81eff1bfc9486e9969d1d71e0334fe69f74ce3;transport=tcp
Record-Route: <sip:192.168.1.2:5060;lr>
Allow: ACK, BYE, CANCEL, INVITE, MESSAGE, NOTIFY, OPTIONS, PRACK, REFER, UPDATE
v=0
o=doubango 1983 678901 IN IP4 192.168.1.1
s=-
c=IN IP4 192.168.1.1
t=0 0
m=audio 17522 RTP/AVP 8 0 101
a=ptime:20
a=silenceSupp:off - - - -
a=rtpmap:8 PCMA/8000/1
a=rtpmap:0 PCMU/8000/1
a=rtpmap:101 telephone-event/8000/1
a=fmtp:101 0-16
a=sendrecv
a=ssrc:1397501633 cname:doubango@1340366314
a=ssrc:1397501633 mslabel:6994f7d1-6ce9-4fbd-acfd-84e5131ca2e2
a=ssrc:1397501633 label:doubango@audio
a=curr:qos local none
a=curr:qos remote none
a=des:qos optional local sendrecv
a=des:qos optional remote sendrecv
a=conf:qos remote sendrecv
Case 2 : INVITE from a UA (by REFER)
As far as I am experienced, this seems to be the most common way of setting up a VoLTE Conference. High level description is
i) a UA make individual VoLTE call with other participants
ii) Merges those individual VoLTE call into a conference all
Overall procedure can be illustrated as shown below. Even though high level procedure sound simple, you would notice that the detailed procedure is much more complicated as illustrated below. Of course, this is not the full sequence. I just put the specific steps that are important for VoLTE Conference setup.
NOTE : In reality, all of these signaling message goes through CSCF and then delivered to final destination(as shown in Case 1 illustration), but in this example I put the arrow between the source and final destination directly without getting CSCF involved just for simplicity.
(A) INVITE
INVITE sip:1234;phone-context=ims.mnc01.mcc001.3gppnetwork.org@ims.mnc01.mcc001.3gppnetwork.org;user=phone SIP/2.0
Supported: timer,100rel,precondition
P-Early-Media: supported
Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY,MESSAGE,PRACK
User-Agent: T-Mobile VoLTEePDG SEC/4.4.4 NK4
Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel"
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=0010100010000000
Session-Expires: 1800;refresher=uac
Min-SE: 90
P-Preferred-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel
Content-Type: application/sdp
Route: <sip:[2001:0:0:1::2]:5060;lr>
P-Preferred-Identity: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>
From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=3750834257
To: <sip:1234;phone-context=ims.mnc01.mcc001.3gppnetwork.org@ims.mnc01.mcc001.3gppnetwork.org;user=phone>
Call-ID: 893977950@2001:0:0:1::1
CSeq: 1 INVITE
Max-Forwards: 70
Contact: <sip:001010123456789@[2001:0:0:1::1]:5060;transport=UDP>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";+sip.instance="<urn:gsma:imei:35459406-311520-0>"
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK3692737244smg;transport=UDP;rport
Content-Length: 755
v=0
o=TEST-IMS-UE 1234567 0 IN IP6 2001:0:0:1::1
s=SS VOIP
c=IN IP6 2001:0:0:1::1
t=0 0
m=audio 1234 RTP/AVP 114 102 113 115 101 105
b=AS:49
b=RS:0
b=RR:0
a=rtpmap:114 AMR-WB/16000/1
a=fmtp:114 mode-change-capability=2;max-red=0
a=rtpmap:102 AMR/8000/1
a=fmtp:102 mode-change-capability=2;max-red=0
a=rtpmap:113 AMR-WB/16000/1
a=fmtp:113 octet-align=1;mode-change-capability=2;max-red=0
a=rtpmap:115 AMR/8000/1
a=fmtp:115 octet-align=1;mode-change-capability=2;max-red=0
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=rtpmap:105 telephone-event/16000
a=fmtp:105 0-15
a=curr:qos local none
a=curr:qos remote none
a=des:qos mandatory local sendrecv
a=des:qos optional remote sendrecv
a=sendrecv
a=ptime:20
a=maxptime:240
(B) INVITE
INVITE sip:1234@[2001:0:0:1::2]:49376;transport=tcp SIP/2.0
Content-Type: application/sdp
Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel"
Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY,MESSAGE,PRACK
P-Preferred-Identity: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=0010100010000000
User-Agent: T-Mobile VoLTEePDG SEC/4.4.4 NK4
Supported: timer
From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=3750834257
To: <sip:1234;phone-context=ims.mnc01.mcc001.3gppnetwork.org@ims.mnc01.mcc001.3gppnetwork.org;user=phone>;tag=0000000012
CSeq: 5 INVITE
Call-ID: 893977950@2001:0:0:1::1
Max-Forwards: 70
Route: <sip:[2001:0:0:1::2]:5060;lr>
Contact: <sip:001010123456789@[2001:0:0:1::1]:5060;transport=UDP>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";+sip.instance="<urn:gsma:imei:35459406-311520-0>"
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK1246892475smg;transport=UDP;rport
Content-Length: 451
v=0
o=TEST-IMS-UE 1234567 2 IN IP6 2001:0:0:1::1
s=SS VOIP
c=IN IP6 2001:0:0:1::1
t=0 0
m=audio 1234 RTP/AVP 114 101
b=AS:49
b=RS:612
b=RR:1837
a=rtpmap:114 AMR-WB/16000/1
a=fmtp:114 mode-change-capability=2;max-red=0
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=curr:qos local sendrecv
a=curr:qos remote sendrecv
a=des:qos mandatory local sendrecv
a=des:qos optional remote sendrecv
a=sendonly
a=ptime:20
a=maxptime:240
(C) INVITE
INVITE sip:2345;phone-context=ims.mnc01.mcc001.3gppnetwork.org@ims.mnc01.mcc001.3gppnetwork.org;user=phone SIP/2.0
Supported: timer,100rel,precondition
P-Early-Media: supported
Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY,MESSAGE,PRACK
User-Agent: T-Mobile VoLTEePDG SEC/4.4.4 NK4
Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel"
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=0010100010000000
Session-Expires: 1800;refresher=uac
Min-SE: 90
P-Preferred-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel
Content-Type: application/sdp
Route: <sip:[2001:0:0:1::2]:5060;lr>
P-Preferred-Identity: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>
From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=2746515092
To: <sip:2345;phone-context=ims.mnc01.mcc001.3gppnetwork.org@ims.mnc01.mcc001.3gppnetwork.org;user=phone>
Call-ID: 2214042697@2001:0:0:1::1
CSeq: 1 INVITE
Max-Forwards: 70
Contact: <sip:001010123456789@[2001:0:0:1::1]:5060;transport=UDP>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";+sip.instance="<urn:gsma:imei:35459406-311520-0>"
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK3243799351smg;transport=UDP;rport
Content-Length: 755
v=0
o=TEST-IMS-UE 1234568 0 IN IP6 2001:0:0:1::1
s=SS VOIP
c=IN IP6 2001:0:0:1::1
t=0 0
m=audio 1244 RTP/AVP 114 102 113 115 101 105
b=AS:49
b=RS:0
b=RR:0
a=rtpmap:114 AMR-WB/16000/1
a=fmtp:114 mode-change-capability=2;max-red=0
a=rtpmap:102 AMR/8000/1
a=fmtp:102 mode-change-capability=2;max-red=0
a=rtpmap:113 AMR-WB/16000/1
a=fmtp:113 octet-align=1;mode-change-capability=2;max-red=0
a=rtpmap:115 AMR/8000/1
a=fmtp:115 octet-align=1;mode-change-capability=2;max-red=0
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=rtpmap:105 telephone-event/16000
a=fmtp:105 0-15
a=curr:qos local none
a=curr:qos remote none
a=des:qos mandatory local sendrecv
a=des:qos optional remote sendrecv
a=sendrecv
a=ptime:20
a=maxptime:240
(D) INVITE
INVITE sip:2345@[2001:0:0:1::2]:49376;transport=tcp SIP/2.0
Content-Type: application/sdp
Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel"
Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY,MESSAGE,PRACK
P-Preferred-Identity: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=0010100010000000
User-Agent: T-Mobile VoLTEePDG SEC/4.4.4 NK4
Supported: timer
From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=2746515092
To: <sip:2345;phone-context=ims.mnc01.mcc001.3gppnetwork.org@ims.mnc01.mcc001.3gppnetwork.org;user=phone>;tag=0000000013
CSeq: 5 INVITE
Call-ID: 2214042697@2001:0:0:1::1
Max-Forwards: 70
Route: <sip:[2001:0:0:1::2]:5060;lr>
Contact: <sip:001010123456789@[2001:0:0:1::1]:5060;transport=UDP>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";+sip.instance="<urn:gsma:imei:35459406-311520-0>"
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK451399630smg;transport=UDP;rport
Content-Length: 451
v=0
o=TEST-IMS-UE 1234568 2 IN IP6 2001:0:0:1::1
s=SS VOIP
c=IN IP6 2001:0:0:1::1
t=0 0
m=audio 1244 RTP/AVP 114 101
b=AS:49
b=RS:612
b=RR:1837
a=rtpmap:114 AMR-WB/16000/1
a=fmtp:114 mode-change-capability=2;max-red=0
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=curr:qos local sendrecv
a=curr:qos remote sendrecv
a=des:qos mandatory local sendrecv
a=des:qos optional remote sendrecv
a=sendonly
a=ptime:20
a=maxptime:240
(E) INVITE
INVITE sip:8881112663@ConferenceFactory.com SIP/2.0
Supported: timer,100rel,precondition
P-Early-Media: supported
Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY,MESSAGE,PRACK
User-Agent: T-Mobile VoLTEePDG SEC/4.4.4 NK4
Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel"
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=0010100010000000
Session-Expires: 1800;refresher=uac
Min-SE: 90
P-Preferred-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel
Content-Type: application/sdp
Route: <sip:[2001:0:0:1::2]:5060;lr>
P-Preferred-Identity: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>
From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=2652816047
To: <sip:8881112663@ConferenceFactory.com>
Call-ID: 2203631692@2001:0:0:1::1
CSeq: 1 INVITE
Max-Forwards: 70
Contact: <sip:001010123456789@[2001:0:0:1::1]:5060;transport=UDP>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";+sip.instance="<urn:gsma:imei:35459406-311520-0>"
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK2400507946smg;transport=UDP;rport
Content-Length: 755
v=0
o=TEST-IMS-UE 1234569 0 IN IP6 2001:0:0:1::1
s=SS VOIP
c=IN IP6 2001:0:0:1::1
t=0 0
m=audio 1246 RTP/AVP 114 102 113 115 101 105
b=AS:49
b=RS:0
b=RR:0
a=rtpmap:114 AMR-WB/16000/1
a=fmtp:114 mode-change-capability=2;max-red=0
a=rtpmap:102 AMR/8000/1
a=fmtp:102 mode-change-capability=2;max-red=0
a=rtpmap:113 AMR-WB/16000/1
a=fmtp:113 octet-align=1;mode-change-capability=2;max-red=0
a=rtpmap:115 AMR/8000/1
a=fmtp:115 octet-align=1;mode-change-capability=2;max-red=0
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=rtpmap:105 telephone-event/16000
a=fmtp:105 0-15
a=curr:qos local none
a=curr:qos remote none
a=des:qos mandatory local sendrecv
a=des:qos optional remote sendrecv
a=sendrecv
a=ptime:20
a=maxptime:240
(F) 183 Session Progress
SIP/2.0 183 Session Progress
Max-Forwards: 70
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK2400507946smg;transport=UDP;rport=5060
From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=2652816047
To: <sip:8881112663@ConferenceFactory.com>;tag=0000000015
Call-ID: 2203631692@2001:0:0:1::1
CSeq: 1 INVITE
Contact: <sip:conference1@[2001:0:0:1::2]:49376;transport=tcp>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";video;isfocus
Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";require;explicit
Record-Route: <sip:[2001:0:0:1::2]:5060;lr>
Require: precondition
Require: 100rel
Supported: precondition
Supported: 100rel
RSeq: 1
Privacy: none
User-Agent: Test-Conference/24ad3b0
Content-Type: application/sdp
Allow-Events: conference
Content-Length: 487
P-Asserted-Identity: <sip:8881112663@ConferenceFactory.com>
v=0
o=Test 162 729163 IN IP6 2001:0:0:1::2
s=-
i=A VOIP Session
c=IN IP6 2001:0:0:1::2
t=0 0
m=audio 60004 RTP/AVP 114 101
b=AS:49
b=RS:0
b=RR:0
a=rtpmap:114 AMR-WB/16000/1
a=fmtp:114 mode-change-capability=2;max-red=0
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=curr:qos local none
a=curr:qos remote none
a=des:qos optional local sendrecv
a=des:qos mandatory remote sendrecv
a=ptime:20
a=maxptime:240
a=conf:qos remote sendrecv
a=sendrecv
a=rtcp:60005
(G) 183 Session Progress
PRACK sip:conference1@[2001:0:0:1::2]:49376;transport=tcp SIP/2.0
RAck: 1 1 INVITE
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=0010100010000000
From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=2652816047
To: <sip:8881112663@ConferenceFactory.com>;tag=0000000015
CSeq: 2 PRACK
Call-ID: 2203631692@2001:0:0:1::1
Max-Forwards: 70
Route: <sip:[2001:0:0:1::2]:5060;lr>
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK129735037smg;transport=UDP;rport
Content-Length: 0
(H) 200 OK
SIP/2.0 200 OK
Max-Forwards: 70
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK129735037smg;transport=UDP;rport=5060
From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=2652816047
To: <sip:8881112663@ConferenceFactory.com>;tag=0000000015
Call-ID: 2203631692@2001:0:0:1::1
CSeq: 2 PRACK
Allow: ACK, BYE, CANCEL, INVITE, NOTIFY, PRACK, REFER, SUBSCRIBE, UPDATE
Contact: <sip:conference1@[2001:0:0:1::2]:49376;transport=tcp>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";video;isfocus
Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";require;explicit
Record-Route: <sip:[2001:0:0:1::2]:5060;lr>
Supported: 100rel
User-Agent: Test-Conference/24ad3b0
Allow-Events: conference
Content-Length: 0
(I) REFER
REFER sip:1234@[2001:0:0:1::2]:49376;transport=tcp SIP/2.0
Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY,MESSAGE,PRACK
P-Preferred-Identity: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>
User-Agent: T-Mobile VoLTEePDG SEC/4.4.4 NK4
Refer-To: <sip:conference1@[2001:0:0:1::2]:49376;transport=tcp;user=phone;method=INVITE>
Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel"
Refer-Sub: true
Event: refer
Supported: norefersub
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=0010100010000000
From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=3750834257
To: <sip:1234;phone-context=ims.mnc01.mcc001.3gppnetwork.org;user=phone>;tag=0000000012
CSeq: 6 REFER
Call-ID: 893977950@2001:0:0:1::1
Max-Forwards: 70
Route: <sip:[2001:0:0:1::2]:5060;lr>
Contact: <sip:001010123456789@[2001:0:0:1::1]:5060;transport=UDP>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";+sip.instance="<urn:gsma:imei:35459406-311520-0>"
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK788055609smg;transport=UDP;rport
Content-Length: 0
(J) 202 Accepted
SIP/2.0 202 Accepted
Max-Forwards: 70
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK788055609smg;transport=UDP;rport=5060
From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=3750834257
To: <sip:1234@ims.mnc01.mcc001.3gppnetwork.org;phone-context=ims.mnc01.mcc001.3gppnetwork.org;user=phone>;tag=0000000012
Call-ID: 893977950@2001:0:0:1::1
CSeq: 6 REFER
Allow: ACK, BYE, CANCEL, INVITE, NOTIFY, PRACK, REFER, UPDATE
Contact: <sip:1234@[2001:0:0:1::2]:49376;transport=tcp>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";video
Record-Route: <sip:[2001:0:0:1::2]:5060;lr>
User-Agent: Test-Conference/24ad3b0
Content-Length: 0
(K) REFER
REFER sip:2345@[2001:0:0:1::2]:49376;transport=tcp SIP/2.0
Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY,MESSAGE,PRACK
P-Preferred-Identity: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>
User-Agent: T-Mobile VoLTEePDG SEC/4.4.4 NK4
Refer-To: <sip:conference1@[2001:0:0:1::2]:49376;transport=tcp;user=phone;method=INVITE>
Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel"
Refer-Sub: true
Event: refer
Supported: norefersub
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=0010100010000000
From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=2746515092
To: <sip:2345;phone-context=ims.mnc01.mcc001.3gppnetwork.org@ims.mnc01.mcc001.3gppnetwork.org;user=phone>;tag=0000000013
CSeq: 6 REFER
Call-ID: 2214042697@2001:0:0:1::1
Max-Forwards: 70
Route: <sip:[2001:0:0:1::2]:5060;lr>
Contact: <sip:001010123456789@[2001:0:0:1::1]:5060;transport=UDP>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";+sip.instance="<urn:gsma:imei:35459406-311520-0>"
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK2797533188smg;transport=UDP;rport
Content-Length: 0
(L) 202 Accepted
SIP/2.0 202 Accepted
Max-Forwards: 70
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK2797533188smg;transport=UDP;rport=5060
From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=2746515092
To: <sip:2345@ims.mnc01.mcc001.3gppnetwork.org;phone-context=ims.mnc01.mcc001.3gppnetwork.org;user=phone>;tag=0000000013
Call-ID: 2214042697@2001:0:0:1::1
CSeq: 6 REFER
Allow: ACK, BYE, CANCEL, INVITE, NOTIFY, PRACK, REFER, UPDATE
Contact: <sip:2345@[2001:0:0:1::2]:49376;transport=tcp>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";video
Record-Route: <sip:[2001:0:0:1::2]:5060;lr>
User-Agent: Test-Conference/24ad3b0
Content-Length: 0