IMS

 

 

 

Early Media

'Early Media' ? Sounds easy, but what does it realy mean ? Why it is called 'Early' media ?

Early Media is a mechanism to enable two users (UAs) to communicate (mainly exchange 'media') BEFORE a call is really established. The keyword is 'media exchange Before call setup'. That is where the word 'EARLY' came from.

Why we need this kind of 'EARLY' stuff ? One of the most important motivation/application is 'Ringback Tone'.

As you know, Ring tone comes before you pick up the phone (i.e, before call setup). Therefore, Early Media can be a good option for Ring tone.

How Early it should be to be early ?

Overall SIP signaling process for Early Media is as follows. In Early Media, a Media is streamed to UA right after 180 Ringing but before 200 OK for INVITE. It means the media is being played before the completion of the VoLTE INVITE session. It means the media plays EARLIER than the normal VoLTE stream and this is why it is called Early Media.

Example 1 : Mode = NRBT, NRBT Model = Forking Mode

Following is an example protocol sequence (SIP sequence and Radio Sequence Consolidated). I would look much more complicated than the illustration above. This is because some of the signaling shown here would show up in a specific condition (so don't be panic if you don't see some of the message not showing up in your log) and some of the steps in the above illustration got expanded into multiple steps in the following sequence.  Just try to understand overall logic and pay special attention to those items that is highlighed in blue or red color.

Step

Direction

Message

Description

1

UA1 -> CSCF

INVITE/SDP

2

UA1 <- CSCF

100 Trying

3

CSCF -> GW/AS

INVITE

4

CSCF <- GW/AS

100 Trying

5

GW/AS -> UA2

INVITE

6

GW/AS <- UA2

100 Trying

7

GW/AS <- UA2

180 Ringing

8

CSCF <- GW/AS

180 Ringing

9

GW/AS -> UA2

PRACK

 

10

CSCF -> GW/AS

PRACK

 

11

GW/AS <- UA2

200 OK

 

12

GW/AS <- UA2

200 OK

 

13

CSCF <- GW/AS

183 Session Progress/SDP

14

UA1 <- CSCF

183 Session Progress/SDP

15

CSCF -> GW/AS

PRACK

16

UA1 -> CSCF

PRACK

17

CSCF <- GW/AS

200 OK

18

UA1 <- CSCF

200 OK

19

UA1 <- NW

RRC CONNECTION RECONFIGURATION

20

UA1 -> NW

RRC CONNECTION RECONFIGURATION COMPLETE

21

UA1 -> NW

ESM: ACTIVATE DEDICATED EPS BEARER CONTEXT ACCEPT

22

UA1 -> CSCF

UPDATE/SDP

23

CSCF ->  UA2

UPDATE/SDP

24

CSCF <-  UA2

200 OK/SDP

25

UA1 <- CSCF

200 OK/SDP

26

UA1 <- NW

ESM: MODIFY EPS BEARER CONTEXT REQUEST

27

UA1 -> NW

ESM: MODIFY EPS BEARER CONTEXT ACCEPT

28

 

< Early Media Streaming >

29

 

< UA 2 Pick Up the Phone (Answering the phone) >

 

30

CSCF <-  UA2

180 Rining

You may or may not see this sequence depending on specific situations

31

CSCF ->  UA2

180 Rining

32

CSCF <-  UA2

PRACK

33

CSCF <-  UA2

183 Session Progress

34

CSCF ->  UA2

183 Session Progress

35

CSCF ->  UA2

PRACK

36

CSCF <-  UA2

200 OK

37

CSCF ->  UA2

200 OK

38

CSCF <-  UA2

200 OK / SDP

This is to INVITE

39

CSCF ->  UA2

200 OK / SDP

40

CSCF <-  UA2

200 OK / SDP

41

UA1 <- CSCF

200 OK / SDP

42

UA1 -> CSCF

ACK

43

UA1 <- CSCF

ACK

44

UA1 <- NW

ESM: MODIFY EPS BEARER CONTEXT REQUEST

45

UA1 -> NW

ESM: MODIFY EPS BEARER CONTEXT ACCEPT

46

 

< VoLTE Streaming >

INVITE>

    INVITE sip:0123456789@msg.sharetechnote.com;user=phone SIP/2.0

    Max-Forwards: 70

    Route: <sip:[2001:0:0:1::2]:50543;lr>

    Via: SIP/2.0/TCP [2001::1:34ee:998c:afe:656f]:39013;branch=z9hG4bK090078f6d-6d3f9587

    Call-ID: 090078e51-6865ba59@2001::1:34ee:998c:afe:656f

    CSeq: 1 INVITE

    From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=54467090078e83-099de555

    To: <sip:0123456789@msg.sharetechnote.com;user=phone>

    Contact: <sip:001010123456789@[2001::1:34ee:998c:afe:656f]:39013;ob>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";video;+g.3gpp.srvcc-alerting;+sip.instance="<urn:gsma:imei:35910506-000422-0>"

    Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";video

    Allow: INVITE,BYE,CANCEL,ACK,PRACK,UPDATE,INFO,REFER,NOTIFY,MESSAGE

    P-Preferred-Identity: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>

    P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=0010100010000000

    Security-Verify: ipsec-3gpp;q=0.1;alg=hmac-md5-96;prot=esp;mod=trans;ealg=null;spi-c=1168670468;spi-s=2529630210;port-c=50542;port-s=50543

    Require: sec-agree

    Supported: 100rel,precondition,timer

    P-Early-Media: supported

    Privacy: none

    Accept: application/sdp,application/3gpp-ims+xml

    Session-Expires: 1800

    User-Agent: Test-client/4.0.0 H81110t

    Proxy-Require: sec-agree

    Content-Length: 758

    Content-Type: application/sdp

     

    v=0

    o=sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org 3677677740 3677677740 IN IP6 2001:0:0:1::11

    s=-

    c=IN IP6 2001:0:0:1::11

    t=0 0

    m=audio 50010 RTP/AVP 97 98 99 100 101 102

    b=AS:49 // RTP Bandwidth

    b=RS:0   // RTCP Send Frequency

    b=RR:1200 // RTCP Report Frequency

    a=rtpmap:97 AMR-WB/16000/1

    a=fmtp:97 mode-change-capability=2

    a=rtpmap:98 AMR-WB/16000/1

    a=fmtp:98 octet-align=1; mode-change-capability=2

    a=rtpmap:99 telephone-event/16000

    a=fmtp:99 0-15

    a=rtpmap:100 AMR/8000/1

    a=fmtp:100 mode-change-capability=2

    a=rtpmap:101 AMR/8000/1

    a=fmtp:101 octet-align=1; mode-change-capability=2

    a=rtpmap:102 telephone-event/8000

    a=fmtp:102 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

 

180 Ringing

    SIP/2.0 180 Ringing

    Max-Forwards: 70

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51411;branch=z9hG4bK4e08ed70d45b4a15ab70d543018f0bc7131;rport;transport=tcp

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51370;branch=z9hG4bKf7c824a224824132a3b9eb00817e4031a8b27ff14d5246;transport=tcp

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51410;branch=z9hG4bK4e08ed70d45b4a15ab70d543018f0bc712f;rport;transport=tcp

    Via: SIP/2.0/TCP [2001::1:1d38:5367:b2a1:e712]:39025;branch=z9hG4bK41312f44a-3ae4266a

    From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=5446741312f3fd-5cd2bed0

    To: <sip:0123456789@msg.sharetechnote.com;user=phone>;tag=1111111111

    Call-ID: 41312f3d6-335e20ae@2001::1:1d38:5367:b2a1:e712

    CSeq: 1 INVITE

    Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";require;explicit

    Record-Route: <sip:[2001:0:0:1::2]:28101;lr>

    Require: 100rel    // require PRACK

    Supported: 100rel

    RSeq: 1

    Privacy: none

    User-Agent: TestUA2/43e5624

    Feature-Caps: +g.3gpp.srvcc-alerting;+g.3gpp.mid-call  

    Content-Length: 0

    Contact: <sip:0123456789@[2001:0:0:1::2]:51364;transport=tcp>;+g.3gpp.icsi-ref="urn:urn-7:3gpp-service.ims.icsi.mmtel";video;+g.3gpp.srvcc-alerting;+g.3gpp.mid-call  

 

183 Session Progress

    SIP/2.0 183 Session Progress

    Max-Forwards: 70

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51410;branch=z9hG4bK4e08ed70d45b4a15ab70d543018f0bc712f;rport;transport=tcp

    Via: SIP/2.0/TCP [2001::1:1d38:5367:b2a1:e712]:39025;branch=z9hG4bK41312f44a-3ae4266a

    From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=5446741312f3fd-5cd2bed0

    To: <sip:0123456789@msg.sharetechnote.com;user=phone>;tag=3333333333

    Call-ID: 41312f3d6-335e20ae@2001::1:1d38:5367:b2a1:e712

    CSeq: 1 INVITE

    P-Early-Media: sendrecv

    RSeq: 1

    Require: 100rel    // require PRACK

    Supported: 100rel

    Require: precondition

    Contact: <sip:0123456789@[2001:0:0:1::2]:51364;transport=tcp>;+g.3gpp.icsi-ref="urn:urn-7:3gpp-service.ims.icsi.mmtel";video;+g.3gpp.srvcc-alerting;+g.3gpp.mid-call

    Record-Route: <sip:[2001:0:0:1::2]:51410;lr>

    User-Agent: sharetechnote-VirtualUA/43e5624

    Content-Type: application/sdp

    Content-Length: 482

     

    v=0

    o=sharetechnote 756 102758 IN IP6 2001:0:0:1::2

    s=-

    i=Early Dialog Session

    c=IN IP6 2001:0:0:1::2

    t=0 0

    m=audio 60000 RTP/AVP 107

    b=AS:38

    b=RS:0

    b=RR:0

    a=fmtp:107 octet-align=1;mode-set=2;mode-change-capability=2;max-red=0

    a=maxptime:20

    a=ptime:20

    a=rtpmap:107 AMR-WB/16000

    a=rtcp:60001

    a=curr:qos local none

    a=curr:qos remote none

    a=des:qos mandatory remote sendrecv

    a=des:qos mandatory local sendrecv

    a=conf:qos remote sendrecv

    a=content:g.3gpp.cat

    a=inactive

 

PRACK

    PRACK sip:0123456789@[2001:0:0:1::2]:51364;transport=tcp SIP/2.0

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51411;branch=z9hG4bK4e08ed70d45b4a15ab70d543018f0bc7133;rport;transport=tcp

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51370; branch=z9hG4bKf7c824a224824132a3b9eb00817e4031533ebe244d5246;transport=tcp

    Max-Forwards: 69

    Call-ID: 41312f3d6-335e20ae@2001::1:1d38:5367:b2a1:e712

    CSeq: 2 PRACK

    To: <sip:0123456789@msg.sharetechnote.com;user=phone>;tag=1111111111

    From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=5446741312f3fd-5cd2bed0

    RAck: 1 1 INVITE

    Require: 100rel

    Supported: precondition

    Supported: 100rel

    Privacy: none

    User-Agent: TestUA2/43e5624

    Content-Length: 0

    Record-Route: <sip:[2001:0:0:1::2]:28101;lr>

 

RRC Connection Reconfiguration

In this step, a dedicated EPS bearer for playing the early media is established and TFT(Traffic Flow Template) for flowing RTP stream. Blue Parts is what you may pay attention to but may vary depending on UE / NW configuration. The Red part is what would the most important parts for the flow to go through.

    rrcConnectionReconfiguration-r8

        dedicatedInfoNASList: 1 item

            Item 0

                DedicatedInfoNAS: 271fc34b39057200c506050126312631172230100840c35a...

                    Non-Access-Stratum (NAS)PDU

                        ...

                        EPS quality of service

                            Length: 5

                            Quality of Service Class Identifier (QCI): QCI 1 (1)

                            Maximum bit rate for uplink : 38 kbps

                            Maximum bit rate for downlink : 49 kbps

                            Guaranteed bit rate for uplink : 38 kbps

                            Guaranteed bit rate for downlink : 49 kbps

                        Traffic Flow Template

                            Length: 23

                            001. .... = TFT operation code: Create new TFT (1)

                            ...0 .... = E bit: Parameters list is not included

                            .... 0010 = Number of packet filters: 2

                            Packet filter 0

                                00.. .... = Spare bit(s): 0

                                ..11 .... = Packet filter direction: Bidirectional (3)

                                .... 0000 = Packet filter identifier: 1 (0)

                                Packet evaluation precedence: 0x10 (16)

                                Packet filter length: 0x08 (8)

                                Packet filter component type identifier: Single local port type(64)

                                    Port:50010 //Port Number for RTP

                                Packet filter component type identifier: Single remote port type(80)

                                    Port: 60000 // Port Number for RTP

                                Packet filter component type identifier: Protocol identifier

                                                                          /Next header type (48)

                                    Protocol/header: UDP (0x11)

                            Packet filter 1

                                00.. .... = Spare bit(s): 0

                                ..11 .... = Packet filter direction: Bidirectional (3)

                                .... 0001 = Packet filter identifier: 2 (1)

                                Packet evaluation precedence: 0x11 (17)

                                Packet filter length: 0x08 (8)

                                Packet filter component type identifier: Single local port type (64)

                                    Port: 50011 // Port Number for RTCP

                                Packet filter component type identifier: Single remote port type (80)

                                    Port: 60001 // Port Number for RTCP

                                Packet filter component type identifier: Protocol identifier

                                                                         /Next header type (48)

                                    Protocol/header: UDP (0x11)

        radioResourceConfigDedicated

            drb-ToAddModList: 1 item

                Item 0

                    DRB-ToAddMod

                        eps-BearerIdentity: 7

                        drb-Identity: 3

                        pdcp-Config

                            discardTimer: ms100 (1)

                            rlc-UM

                        rlc-Config: um-Bi-Directional (1)

                        logicalChannelIdentity: 5

                        logicalChannelConfig

                            ul-SpecificParameters

                                priority: 6

                                prioritisedBitRate: kBps8 (1)

                                bucketSizeDuration: ms100 (1)

                                logicalChannelGroup: 1

            mac-MainConfig: explicitValue (0)

                explicitValue

                    ul-SCH-Config

                    drx-Config: setup (1)

                    timeAlignmentTimerDedicated: infinity (7)

                    phr-Config: setup (1)

                    mac-MainConfig-v1020

            physicalConfigDedicated

                tpc-PDCCH-ConfigPUCCH: setup (1)

                tpc-PDCCH-ConfigPUSCH: setup (1)

                antennaInfo: defaultValue (1)

                    defaultValue: NULL

 

UPDATE/SDP

    UPDATE sip:0123456789@[2001:0:0:1::2]:51364;transport=tcp SIP/2.0

    Max-Forwards: 70

    Route: <sip:[2001:0:0:1::2]:62933;lr>

    Via: SIP/2.0/TCP [2001::1:1d38:5367:b2a1:e712]:39025;branch=z9hG4bK4131d902e-3d63d9ef

    Call-ID: 41312f3d6-335e20ae@2001::1:1d38:5367:b2a1:e712

    CSeq: 3 UPDATE

    From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=5446741312f3fd-5cd2bed0

    To: <sip:0123456789@msg.sharetechnote.com;user=phone>;tag=3333333333

    Contact: <sip:001010123456789@[2001::1:1d38:5367:b2a1:e712]:39025;ob>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";video;+g.3gpp.srvcc-alerting;+sip.instance="<urn:gsma:imei:35910506-000422-0>"

    Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";video

    Allow: INVITE, BYE, CANCEL, ACK, PRACK, UPDATE, INFO, REFER, NOTIFY, MESSAGE

    P-Preferred-Identity: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>

    P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=0010100010000000

    Security-Verify: ipsec-3gpp;q=0.1;alg=hmac-md5-96;prot=esp;mod=trans;ealg=null;spi-c=3971908422;spi-s=1501624932;port-c=62932;port-s=62933

    Require: precondition, sec-agree

    Supported: precondition

    User-Agent: SHARETECH TEST-IMS-client/4.0.0 H81110t

    Proxy-Require: sec-agree

    Content-Length: 462

    Content-Type: application/sdp

     

    v=0

    o=sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org 3677690491 3677690492 IN IP6 2001:0:0:1::11

    s=-

    c=IN IP6 2001:0:0:1::11

    t=0 0

    m=audio50010 RTP/AVP 107

    b=AS:38 // RTP Bandwidth. This is different from AS in INVITE/SDP,

                // so it will trigger ESM: MODIFY EPS BEARER CONTEXT REQUEST in Radio Access Network

    b=RS:0 // RTCP Send Frequency

    b=RR:900 // RTCP Report Frequency

    a=rtpmap:107 AMR-WB/16000

    a=fmtp:107 mode-set=2; octet-align=1; mode-change-capability=2; max-red=0

    a=curr:qos local sendrecv

    a=curr:qos remote none

    a=des:qos mandatory local sendrecv

    a=des:qos mandatory remote sendrecv

    a=sendrecv

    a=ptime:20

    a=maxptime:240

 

200 OK/SDP

    SIP/2.0 200 OK

    Max-Forwards: 70

    Via: SIP/2.0/TCP [2001::1:1d38:5367:b2a1:e712]:39025;branch=z9hG4bK4131d902e-3d63d9ef

    From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=5446741312f3fd-5cd2bed0

    To: <sip:0123456789@msg.sharetechnote.com;user=phone>;tag=3333333333

    Call-ID: 41312f3d6-335e20ae@2001::1:1d38:5367:b2a1:e712

    CSeq: 3 UPDATE

    Allow: INVITE, UPDATE, BYE, CANCEL, ACK, PRACK

    Contact: <sip:[2001:0:0:1::2]:51370;transport=tcp>

    Record-Route: <sip:[2001:0:0:1::2]:62933;lr>

    Require: precondition

    User-Agent: sharetechnote-VirtualUA/43e5624

    Content-Type: application/sdp

    Content-Length: 490

    Privacy: none

     

    v=0

    o=sharetechnote 756 102759 IN IP6 2001:0:0:1::2

    s=-

    i=Early Dialog Session

    c=IN IP6 2001:0:0:1::2

    t=0 0

    m=audio60000 RTP/AVP 107

    b=AS:38 // RTP Bandwidth. This is different from AS in INVITE/SDP,

                 /// so it will trigger ESM: MODIFY EPS BEARER CONTEXT REQUEST in Radio Access Network

    b=RS:0  // RTCP Send Frequency

    b=RR:0  // RTCP Report Frequency

    a=fmtp:107 octet-align=1;mode-set=2;mode-change-capability=2;max-red=0

    a=maxptime:20

    a=ptime:20

    a=rtpmap:107 AMR-WB/16000

    a=rtcp:60001

    a=curr:qos local sendrecv

    a=curr:qos remote sendrecv

    a=des:qos mandatory remote sendrecv

    a=des:qos mandatory local sendrecv

    a=conf:qos remote sendrecv

    a=content:g.3gpp.cat

    a=sendrecv

 

ESM: MODIFY EPS BEARER CONTEXT REQUEST

This is to Adjust the NAS layer throughput according the the specified bandwidth in SIP:UPDATE/SDP

    dlInformationTransfer-r8

         dedicatedInfoType: dedicatedInfoNAS (0)

             dedicatedInfoNAS: 27399eeab8067200c95b050126262626

                 Non-Access-Stratum (NAS)PDU

                     0010 .... = Security header type: Integrity protected and ciphered (2)

                     .... 0111 = Protocol discriminator: EPS mobility management messages (0x07)

                     Message authentication code: 0x399eeab8

                     Sequence number: 6

                     0111 .... = EPS bearer identity: EPS bearer identity value 7 (7)

                     .... 0010 = Protocol discriminator: EPS session management messages (0x02)

                     Procedure transaction identity: 0

                     NAS EPS session management messages: Modify EPS bearer context request (0xc9)

                     EPS quality of service - New EPS QoS

                         Element ID: 0x5b

                         Length: 5

                         Quality of Service Class Identifier (QCI): QCI 1 (1)

                         Maximum bit rate for uplink : 38 kbps

                         Maximum bit rate for downlink : 38 kbps

                         Guaranteed bit rate for uplink : 38 kbps

                         Guaranteed bit rate for downlink : 38 kbps

 

200 OK / SDP

    SIP/2.0 200 OK

    Max-Forwards: 70

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51411;branch=z9hG4bK4e08ed70d45b4a15ab70d543018f0bc7131;rport;transport=tcp

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51370;branch=z9hG4bKf7c824a224824132a3b9eb00817e4031a8b27ff14d5246;transport=tcp

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51410;branch=z9hG4bK4e08ed70d45b4a15ab70d543018f0bc712f;rport;transport=tcp

    Via: SIP/2.0/TCP [2001::1:1d38:5367:b2a1:e712]:39025;branch=z9hG4bK41312f44a-3ae4266a

    From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=5446741312f3fd-5cd2bed0

    To: <sip:0123456789@msg.sharetechnote.com;user=phone>;tag=1111111111

    Call-ID: 41312f3d6-335e20ae@2001::1:1d38:5367:b2a1:e712

    CSeq: 1 INVITE

    Allow: ACK, BYE, CANCEL, INVITE, PRACK, UPDATE

    Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";require;explicit

    Record-Route: <sip:[2001:0:0:1::2]:28101;lr>

    User-Agent: sharetechnote-VirtualUA/43e5624

    Content-Type: application/sdp

    Content-Length: 732

    Contact: <sip:0123456789@[2001:0:0:1::2]:51364;transport=tcp>;+g.3gpp.icsi-ref="urn:urn-7:3gpp-service.ims.icsi.mmtel";video;+g.3gpp.srvcc-alerting;+g.3gpp.mid-call

     

    v=0

    o=sharetechnote 784 552784 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 60002 RTP/AVP 97 98 99 100 101 102

    b=AS:49 // RTP Bandwidth. This is different from AS in Previous SDP (UPDATE/SDP),

                 // so it will trigger ESM: MODIFY EPS BEARER CONTEXT REQUEST in Radio Access Network

    b=RS:0

    b=RR:1200

    a=rtpmap:97 AMR-WB/16000/1

    a=fmtp:97 mode-change-capability=2

    a=rtpmap:98 AMR-WB/16000/1

    a=fmtp:98 octet-align=1; mode-change-capability=2

    a=rtpmap:99 telephone-event/16000

    a=fmtp:99 0-15

    a=rtpmap:100 AMR/8000/1

    a=fmtp:100 mode-change-capability=2

    a=rtpmap:101 AMR/8000/1

    a=fmtp:101 octet-align=1; mode-change-capability=2

    a=rtpmap:102 telephone-event/8000

    a=fmtp:102 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=ptime:20

    a=maxptime:240

    a=sendrecv

    a=rtcp:60003

 

200 OK / SDP

    SIP/2.0 200 OK

    Max-Forwards: 70

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51370;branch=z9hG4bKf7c824a224824132a3b9eb00817e4031a8b27ff14d5246;transport=tcp

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51410;branch=z9hG4bK4e08ed70d45b4a15ab70d543018f0bc712f;rport;transport=tcp

    Via: SIP/2.0/TCP [2001::1:1d38:5367:b2a1:e712]:39025;branch=z9hG4bK41312f44a-3ae4266a

    From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=5446741312f3fd-5cd2bed0

    To: <sip:0123456789@msg.sharetechnote.com;user=phone>;tag=1111111111

    Call-ID: 41312f3d6-335e20ae@2001::1:1d38:5367:b2a1:e712

    CSeq: 1 INVITE

    Allow: ACK, BYE, CANCEL, INVITE, PRACK, UPDATE

    Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";require;explicit

    Record-Route: <sip:[2001:0:0:1::2]:51410;lr>

    User-Agent: sharetechnote-VirtualUA/43e5624

    Content-Type: application/sdp

    Content-Length: 732

    Contact: <sip:0123456789@[2001:0:0:1::2]:51364;transport=tcp>;+g.3gpp.icsi-ref="urn:urn-7:3gpp-service.ims.icsi.mmtel";video;+g.3gpp.srvcc-alerting;+g.3gpp.mid-call

    Privacy: none

    P-Asserted-Identity: <sip:0123456789@msg.sharetechnote.com;user=phone>

     

    v=0

    o=sharetechnote 784 552784 IN IP6 2001:0:0:1::2

    s=-

    i=A VOIP Session

    c=IN IP6 2001:0:0:1::2

    t=0 0

    m=audio60002 RTP/AVP 97 98 99 100 101 102

    b=AS:49  // RTP Bandwidth. This is different from AS in Previous SDP (UPDATE/SDP),

                 // so it will trigger ESM: MODIFY EPS BEARER CONTEXT REQUEST in Radio Access Network

    b=RS:0

    b=RR:1200

    a=rtpmap:97 AMR-WB/16000/1

    a=fmtp:97 mode-change-capability=2

    a=rtpmap:98 AMR-WB/16000/1

    a=fmtp:98 octet-align=1; mode-change-capability=2

    a=rtpmap:99 telephone-event/16000

    a=fmtp:99 0-15

    a=rtpmap:100 AMR/8000/1

    a=fmtp:100 mode-change-capability=2

    a=rtpmap:101 AMR/8000/1

    a=fmtp:101 octet-align=1; mode-change-capability=2

    a=rtpmap:102 telephone-event/8000

    a=fmtp:102 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=ptime:20

    a=maxptime:240

    a=sendrecv

    a=rtcp:60003

 

200 OK / SDP

    SIP/2.0 200 OK

    Max-Forwards: 70

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51410;branch=z9hG4bK4e08ed70d45b4a15ab70d543018f0bc712f;rport;transport=tcp

    Via: SIP/2.0/TCP [2001::1:1d38:5367:b2a1:e712]:39025;branch=z9hG4bK41312f44a-3ae4266a

    From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=5446741312f3fd-5cd2bed0

    To: <sip:0123456789@msg.sharetechnote.com;user=phone>;tag=1111111111

    Call-ID: 41312f3d6-335e20ae@2001::1:1d38:5367:b2a1:e712

    CSeq: 1 INVITE

    Allow: ACK, BYE, CANCEL, INVITE, PRACK, UPDATE

    Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";require;explicit

    Record-Route: <sip:[2001:0:0:1::2]:51410;lr>

    User-Agent: sharetechnote-VirtualUA/43e5624

    Content-Type: application/sdp

    Content-Length: 732

    Contact: <sip:0123456789@[2001:0:0:1::2]:51364;transport=tcp>;+g.3gpp.icsi-ref="urn:urn-7:3gpp-service.ims.icsi.mmtel";video;+g.3gpp.srvcc-alerting;+g.3gpp.mid-call

    Privacy: none

    P-Asserted-Identity: <sip:0123456789@msg.sharetechnote.com;user=phone>

     

    v=0

    o=sharetechnote 784 552784 IN IP6 2001:0:0:1::2

    s=-

    i=A VOIP Session

    c=IN IP6 2001:0:0:1::2

    t=0 0

    m=audio60002 RTP/AVP 97 98 99 100 101 102

    b=AS:49

    b=RS:0

    b=RR:1200

    a=rtpmap:97 AMR-WB/16000/1

    a=fmtp:97 mode-change-capability=2

    a=rtpmap:98 AMR-WB/16000/1

    a=fmtp:98 octet-align=1; mode-change-capability=2

    a=rtpmap:99 telephone-event/16000

    a=fmtp:99 0-15

    a=rtpmap:100 AMR/8000/1

    a=fmtp:100 mode-change-capability=2

    a=rtpmap:101 AMR/8000/1

    a=fmtp:101 octet-align=1; mode-change-capability=2

    a=rtpmap:102 telephone-event/8000

    a=fmtp:102 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=ptime:20

    a=maxptime:240

    a=sendrecv

    a=rtcp:60003

 

200 OK / SDP

    SIP/2.0 200 OK

    Max-Forwards: 70

    Via: SIP/2.0/TCP [2001::1:1d38:5367:b2a1:e712]:39025;branch=z9hG4bK41312f44a-3ae4266a

    From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=5446741312f3fd-5cd2bed0

    To: <sip:0123456789@msg.sharetechnote.com;user=phone>;tag=1111111111

    Call-ID: 41312f3d6-335e20ae@2001::1:1d38:5367:b2a1:e712

    CSeq: 1 INVITE

    Allow: ACK, BYE, CANCEL, INVITE, PRACK, UPDATE

    Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";require;explicit

    Record-Route: <sip:[2001:0:0:1::2]:62933;lr>

    User-Agent: sharetechnote-VirtualUA/43e5624

    Content-Type: application/sdp

    Content-Length: 732

    Contact: <sip:0123456789@[2001:0:0:1::2]:51364;transport=tcp>;+g.3gpp.icsi-ref="urn:urn-7:3gpp-service.ims.icsi.mmtel";video;+g.3gpp.srvcc-alerting;+g.3gpp.mid-call

    P-Asserted-Identity: <sip:0123456789@msg.sharetechnote.com;user=phone>

    Privacy: none

     

    v=0

    o=sharetechnote 784 552784 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 60002 RTP/AVP 97 98 99 100 101 102

    b=AS:49

    b=RS:0

    b=RR:1200

    a=rtpmap:97 AMR-WB/16000/1

    a=fmtp:97 mode-change-capability=2

    a=rtpmap:98 AMR-WB/16000/1

    a=fmtp:98 octet-align=1; mode-change-capability=2

    a=rtpmap:99 telephone-event/16000

    a=fmtp:99 0-15

    a=rtpmap:100 AMR/8000/1

    a=fmtp:100 mode-change-capability=2

    a=rtpmap:101 AMR/8000/1

    a=fmtp:101 octet-align=1; mode-change-capability=2

    a=rtpmap:102 telephone-event/8000

    a=fmtp:102 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=ptime:20

    a=maxptime:240

    a=sendrecv

    a=rtcp:60003

 

ACK

    ACK sip:0123456789@[2001:0:0:1::2]:51364;transport=tcp SIP/2.0

    Max-Forwards: 70

    Route: <sip:[2001:0:0:1::2]:62933;lr>

    Via: SIP/2.0/UDP [2001::1:1d38:5367:b2a1:e712]:39025;branch=z9hG4bK4238bb47b-3b6ff5e5

    Call-ID: 41312f3d6-335e20ae@2001::1:1d38:5367:b2a1:e712

    CSeq: 1 ACK

    From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=5446741312f3fd-5cd2bed0

    To: <sip:0123456789@msg.sharetechnote.com;user=phone>;tag=1111111111

    Allow: INVITE, BYE, CANCEL, ACK, PRACK, UPDATE, INFO, REFER, NOTIFY, MESSAGE

    Require: sec-agree

    User-Agent: SHARETECH TEST-IMS-client/4.0.0 H81110t

    Proxy-Require: sec-agree

    Content-Length: 0

 

ACK

    ACK sip:0123456789@[2001:0:0:1::2]:51364;transport=tcp SIP/2.0

    Via: SIP/2.0/TCP [2001:0:0:1::2]:51411;branch=z9hG4bK4e08ed70d45b4a15ab70d543018f0bc7138;rport;transport=tcp

    Max-Forwards: 69

    Via: SIP/2.0/UDP [2001::1:1d38:5367:b2a1:e712]:39025;branch=z9hG4bK4238bb47b-3b6ff5e5

    Call-ID: 41312f3d6-335e20ae@2001::1:1d38:5367:b2a1:e712

    CSeq: 1 ACK

    From: <sip:001010123456789@ims.mnc01.mcc001.3gppnetwork.org>;tag=5446741312f3fd-5cd2bed0

    To: <sip:0123456789@msg.sharetechnote.com;user=phone>;tag=1111111111

    Allow: INVITE, BYE, CANCEL, ACK, PRACK, UPDATE, INFO, REFER, NOTIFY, MESSAGE

    User-Agent: SHARETECH TEST-IMS-client/4.0.0 H81110t

    Content-Length: 0

 

ESM : MODIFY EPS BEARER CONTEXT REQUEST

    dlInformationTransfer-r8

        dedicatedInfoType: dedicatedInfoNAS (0)

            dedicatedInfoNAS: 27f7fbaafa077200c95b05013131313136178230100840c3...

                Non-Access-Stratum (NAS)PDU

                    0010 .... = Security header type: Integrity protected and ciphered (2)

                    .... 0111 = Protocol discriminator: EPS mobility management messages (0x07)

                    Message authentication code: 0xf7fbaafa

                    Sequence number: 7

                    0111 .... = EPS bearer identity: EPS bearer identity value 7 (7)

                    .... 0010 = Protocol discriminator: EPS session management messages (0x02)

                    Procedure transaction identity: 0

                    NAS EPS session management messages: Modify EPS bearer context request (0xc9)

                    EPS quality of service - New EPS QoS

                        Element ID: 0x5b

                        Length: 5

                        Quality of Service Class Identifier (QCI): QCI 1 (1)

                        Maximum bit rate for uplink : 49 kbps

                        Maximum bit rate for downlink : 49 kbps

                        Guaranteed bit rate for uplink : 49 kbps

                        Guaranteed bit rate for downlink : 49 kbps

                    Traffic Flow Template

                        Element ID: 0x36

                        Length: 23

                        100. .... = TFT operation code: Replace packet filters in existing TFT (4)

                        ...0 .... = E bit: Parameters list is not included

                        .... 0010 = Number of packet filters: 2

                        Packet filter 0

                            00.. .... = Spare bit(s): 0

                            ..11 .... = Packet filter direction: Bidirectional (3)

                            .... 0000 = Packet filter identifier: 1 (0)

                            Packet evaluation precedence: 0x10 (16)

                            Packet filter length: 0x08 (8)

                            Packet filter component type identifier: Single local port type (64)

                                Port: 50010

                            Packet filter component type identifier: Single remote port type (80)

                                Port: 60002

                            Packet filter component type identifier: Protocol identifier

                                                                     /Next header type (48)

                                Protocol/header: UDP (0x11)

                        Packet filter 1

                            00.. .... = Spare bit(s): 0

                            ..11 .... = Packet filter direction: Bidirectional (3)

                            .... 0001 = Packet filter identifier: 2 (1)

                            Packet evaluation precedence: 0x11 (17)

                            Packet filter length: 0x08 (8)

                            Packet filter component type identifier: Single local port type (64)

                                Port: 50011

                            Packet filter component type identifier: Single remote port type (80)

                                Port: 60003

                            Packet filter component type identifier: Protocol identifier

                                                                     /Next header type (48)

                                Protocol/header: UDP (0x11)

Further Reading :

[1] SIP Media Management: Early Offer vs. Late Offer

[2] SIP Media Management: Early Media vs. Late Media

[3] RFC 3960 Early Media and Ringing Tone Generation in SIP  

[3] RFC 5009 - 8.The P-Early-Media Header Field

[3] 3GPP 24.229

[4] 3GPP 24.268

    A.5 Providing announcements to a terminating user just after the call is answered and before establishing direct communication session between end users