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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