F.2 PS to CS SRVCC
24.2373GPPIP Multimedia (IM) Core Network (CN) subsystem IP Multimedia Subsystem (IMS) service continuityRelease 17Stage 3TS
F.2.1 Key to interpret PS to CS SRVCC access transfer scenarios
The key to interpret the PS to CS SRVCC access transfer scenarios given in tables F.2. 2-1, F.2.2-2 and F.2.3-1 is specified below:
– "MAM" represents support of MSC server assisted mid-call feature
– "ALP" represents support of PS to CS SRVCC for calls in alerting phase
– "PAP" represents support of PS to CS SRVCC for originating calls in pre-alerting phase
– "CAS" represents a session with active speech media component, which is a confirmed dialog
– "CIS" represents a session with inactive speech media component, which is a confirmed dialog
– "EAS" represents a session with active speech media component in alerting phase
– "EAST" represents a terminating session with active speech media component in alerting phase
– "EASO" represents an originating session with active speech media component in alerting phase
– "EPS" represents a session with active speech media component in pre-alerting phase
– "EPST" represents a terminating session with active speech media component in pre-alerting phase
– "EPSO" represents an originating session with active speech media component in pre-alerting phase
– "CACS" represents a session with active speech media component and with conference control, which is a confirmed dialog
– "CICS" represents a session with inactive speech media component and with conference control, which is a confirmed dialog
– "Transfer CACS as CAS" refers to the behaviour of the SCC AS to transfer CACS, but without conference control
– "Transfer CICS as CIS" refers to the behaviour of the SCC AS to transfer CICS, but without conference control
– When "Result in network" is to transfer a session, the Transaction Identifier (TI) assigned to the call is shown in brackets, e.g. Transfer CAS (TI=0) refers to a TI of zero assigned to this call that is transferred.
F.2.2 PS to CS SRVCC access transfer scenarios
Table F.2.2-1 describes PS to CS SRVCC access transfer scenarios considering only cases when only one session in an early phase exists.
Table F.2.2-1: PS to CS SRVCC access transfer scenarios, single early session
UE and Network Support Combination |
Access Transfer Scenario |
Result in network |
UE supports at least MAM and Network supports MAM only or UE supports MAM only and Network supports at least MAM |
CAS only |
Transfer CAS (TI=0) |
CIS only |
Transfer CIS (TI=0) |
|
EAS only |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
EPS only |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
CAS + CIS |
Transfer CAS (TI=0) and transfer CIS (TI=1) |
|
CAS + EAST |
Transfer CAS (TI=0) and release EAST |
|
CAS + EPST |
Transfer CAS (TI=0) and release EPST |
|
CIS + EASO |
Transfer CIS (TI=0) and release EASO |
|
CIS + EAST |
Transfer CIS (TI=0) and release EAST |
|
CIS + EPSO |
Transfer CIS (TI=0) and release EPSO |
|
CAS + CIS + EAST |
Transfer CAS (TI=0), transfer CIS (TI=1) and release EAST |
|
CAS + CIS + EPST |
Transfer CAS (TI=0), transfer CIS (TI=1) and release EPST |
|
UE supports ALP only and Network supports at least ALP or UE supports at least ALP and network supports ALP only |
CAS only |
Transfer CAS (TI=0) |
CIS only |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
EAS only |
Transfer EAS (TI=0) |
|
EPS only |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
CAS + CIS |
Transfer CAS (TI=0) and release CIS |
|
CAS + EAST |
Transfer CAS (TI=0) and transfer EAST (TI=1) |
|
CAS + EPST |
Transfer CAS (TI=0) and release EPST |
|
CIS + EASO |
Transfer EASO (TI=0) and release CIS |
|
CIS + EAST |
Transfer EAST (TI=0) and release CIS |
|
CIS + EPSO |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
CAS + CIS + EAST |
Transfer CAS (TI=0), transfer EAST (TI=1) and release CIS |
|
CAS + CIS + EPST |
Transfer CAS (TI=0), release CIS, release EPST |
|
UE supports ALP+PAP only and Network supports at least ALP+PAP or UE supports at least ALP+PAP and Network supports ALP+PAP only |
CAS only |
Transfer CAS (TI=0) |
CIS only |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
EAS only |
Transfer EAS (TI=0) |
|
EPSO only |
Transfer EPSO (TI=0) |
|
EPST only |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
CAS + CIS |
Transfer CAS (TI=0) and release CIS |
|
CAS + EAST |
Transfer CAS (TI=0) and transfer EAST (TI=1) |
|
CAS + EPST |
Transfer CAS (TI=0) and release EPST |
|
CIS + EASO |
Transfer EASO (TI=0) and release CIS |
|
CIS + EAST |
Transfer EAST (TI=0) and release CIS |
|
CIS + EPSO |
Transfer EPSO (TI=0) and release CIS |
|
CAS + CIS + EAST |
Transfer CAS (TI=0), transfer EAST (TI=1) and release CIS |
|
CAS + CIS + EPST |
Transfer CAS (TI=0), release CIS, release EPST |
|
UE and Network support MAM+ALP+PAP |
CAS only |
Transfer CAS (TI=0) |
CIS only |
Transfer CIS (TI=0) |
|
EAS only |
Transfer EAS (TI=0) |
|
EPSO only |
Transfer EPSO (TI=0) |
|
EPST only |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
CAS + CIS |
Transfer CAS (TI=0) and transfer CIS (TI=1) |
|
CAS + EAST |
Transfer CAS (TI=0) and transfer EAST (TI=1) |
|
CAS + EPST |
Transfer CAS (TI=0) and release EPST |
|
CIS + EASO |
Transfer CIS (TI=0) and transfer EASO (TI=1) |
|
CIS + EAST |
Transfer CIS (TI=0) and transfer EAST (TI=1) |
|
CIS + EPSO |
Transfer CIS (TI=0) and transfer EPSO (TI=1) |
|
CAS + CIS + EAST |
Transfer CAS (TI=0), transfer CIS (TI=1) and release EAST NOTE 1: Even though the UE and network can support the transfer of EAST, the network will only transfer CAS and CIS and will release EAST. |
|
CAS + CIS + EPST |
Transfer CAS (TI=0), transfer CIS (TI=1) and release EPST |
|
UE supports MAM+ ALP only and Network supports at least MAM+ALP or UE supports at least MAM+ ALP and Network supports MAM+ALP only |
CAS only |
Transfer CAS (TI=0) |
CIS only |
Transfer CIS (TI=0) |
|
EAS only |
Transfer EAS (TI=0) |
|
EPS only |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
CAS + CIS |
Transfer CAS (TI=0) and transfer CIS (TI=1) |
|
CAS + EAST |
Transfer CAS (TI=0) and transfer EAST (TI=1) |
|
CAS + EPST |
Transfer CAS (TI=0) and release EPST |
|
CIS + EASO |
Transfer CIS (TI=0) and transfer EASO (TI=1) |
|
CIS + EAST |
Transfer CIS (TI=0) and transfer EAST (TI=1) |
|
CIS + EPSO |
Transfer CIS (TI=0) and release EPSO |
|
CAS + CIS + EAST |
Transfer CAS (TI=0), transfer CIS (TI=1) and release EAST NOTE 2: Even though the UE and network can support the transfer of EAST, the network will only transfer CAS and CIS and will release EAST. |
|
CAS + CIS + EPST |
Transfer CAS (TI=0), Transfer CIS (TI=1), release EPST |
|
UE has no MAM support and Network supports MAM only or UE supports MAM only and Network has no MAM support |
CAS only |
Transfer CAS (TI=0) |
CIS only |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
EAS only |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
EPS only |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
CAS + CIS |
Transfer CAS (TI=0) and release CIS |
|
CAS + EAST |
Transfer CAS (TI=0) and release EAST |
|
CAS + EPST |
Transfer CAS (TI=0) and release EPST |
|
CIS + EASO |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
CIS + EAST |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
CIS + EPSO |
Send SIP 480 (Temporary Unavailable) to reject SIP INVITE request due to STN-SR |
|
CAS + CIS + EAST |
Transfer CAS (TI=0), release CIS and release EAST |
|
CAS + CIS + EPST |
Transfer CAS (TI=0), release CIS and release EPST |
Table F.2.2-2 below describes PS to CS SRVCC access transfer scenarios when more than one session in an early phase exists and when the UE and the network supports SRVCC access transfer for calls in an early phase.
Table F.2.2-2: PS to CS SRVCC access transfer scenarios, multiple early sessions
UE and Network Support Combination |
Access Transfer Scenario |
Result in network |
UE supports ALP only and Network supports at least ALP or UE supports at least ALP and network supports ALP only |
EASO + EAST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
EPSO + EPST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
EAS + EPS |
Transfer EAS (TI=0) and release EPS |
|
CAS + EAS + EPS |
Transfer CAS (TI=0), transfer EAS (TEI=1) and release EPS |
|
CAS + EASO + EAST |
Transfer CAS (TI=0), release EASO and release EAST |
|
CIS + EAS + EPS |
Transfer EAS (TI=0), release CIS and release EPS |
|
CIS + EASO + EAST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
CIS + EPSO + EPST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
UE supports ALP+PAP only and Network supports at least ALP+PAP or UE supports at least ALP+PAP and Network supports ALP+PAP only |
EASO + EAST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
EPSO + EPST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
EAS + EPS |
Transfer EAS (TI=0) and release EPS |
|
CAS + EAS + EPS |
Transfer CAS (TI=0), transfer EAS (TI=1) and release EPS |
|
CAS + EASO + EAST |
Transfer CAS (TI=0), release EASO and release EAST |
|
CIS + EAS + EPS |
Transfer EAS (TI=0), release CIS and release EPS |
|
CIS + EASO + EAST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
CIS + EPSO + EPST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
UE and Network support MAM+ALP+PAP |
EASO + EAST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
EPSO + EPST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
EAS + EPS |
Transfer EAS (TI=0) and release EPS |
|
CAS + EAS + EPS |
Transfer CAS (TI=0), transfer EAS (TI=1) and release EPS |
|
CAS + EASO + EAST |
Transfer CAS (TI=0), release EASO and release EAST |
|
CIS + EAS + EPS |
Transfer CIS (TI=0), transfer EAS (TI=1) and release EPS |
|
CIS + EASO + EAST |
Transfer CIS (TI=0), release EASO and release EAST |
|
CIS + EPSO + EPST |
Transfer CIS (TI=0), release EPSO and release EPST |
|
UE supports MAM+ ALP only and Network supports at least MAM+ALP or UE supports at least MAM+ ALP and Network supports MAM+ALP only |
EASO + EAST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
EPSO + EPST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
EAS + EPS |
Transfer EAS (TI=0) and release EPS |
|
CAS + EAS + EPS |
Transfer CAS (TI=0), transfer EAS (TI=1) and release EPS |
|
CAS + EASO + EAST |
Transfer CAS (TI=0), release EASO and release EAST |
|
CIS + EAS + EPS |
Transfer CIS (TI=0), transfer EAS (TI=1) and release EPS |
|
CIS + EASO + EAST |
Transfer CIS (TI=0), release EASO and release EAST |
|
CIS + EPSO + EPST |
Transfer CIS (TI=0), release EPSO and release EPST |
F.2.3 PS to CS SRVCC access transfer scenarios with conference control
Table F.2.3-1: PS to CS SRVCC access transfer scenarios with conference control
UE and Network Support Combination |
Access Transfer Scenario |
Result in network |
UE supports at least MAM and Network supports MAM only or UE supports MAM only and Network supports at least MAM |
CACS only |
Transfer CACS (NOTE 1) |
CICS only |
Transfer CICS (NOTE 1) |
|
CACS + CIS |
Transfer CACS (NOTE 1) and transfer CIS (TI=1) |
|
CAS + CICS |
Transfer CAS (TI=0) and transfer CICS (NOTE 2) |
|
CACS + EAST |
Transfer CACS (NOTE 1) and release EAST |
|
CACS + EPST |
Transfer CACS (NOTE 1) and release EPST |
|
CICS + EASO |
Transfer CICS (NOTE 1) and release EASO |
|
CICS + EAST |
Transfer CICS (NOTE 1) and release EAST |
|
CICS + EPSO |
Transfer CICS (NOTE 1) and release EPSO |
|
CACS + CIS + EAST |
Transfer CACS (NOTE 1), transfer CIS (TI=1) and release EAST |
|
CAS + CICS + EAST |
Transfer CAS (TI=0), transfer CICS (NOTE 2) and release EAST |
|
CACS + CIS + EPST |
Transfer CACS (NOTE 1), transfer CIS (TI=1) and release EPST |
|
CAS + CICS + EPST |
Transfer CAS (TI=0), transfer CICS (NOTE 2) and release EPST |
|
CACS + CICS |
Transfer CACS (NOTE 1) and transfer CICS as CIS (TI=1) |
|
CACS + CICS + EAST |
Transfer CACS (NOTE 1), transfer CICS as CIS (TI=1) and release EAST |
|
CACS + CICS + EPST |
Transfer CACS (NOTE 1), transfer CICS as CIS (TI=1) and release EPST |
|
UE supports ALP only and Network supports at least ALP or UE supports at least ALP and network supports ALP only |
CACS only |
Transfer CACS as CAS (TI=0) |
CICS only |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
CACS + CIS |
Transfer CACS as CAS (TI=0) and release CIS |
|
CAS + CICS |
Transfer CAS (TI=0) and release CICS |
|
CACS + EAST |
Transfer CACS as CAS (TI=0) and transfer EAST (TI=1) |
|
CACS + EPST |
Transfer CACS as CAS (TI=0) and release EPST |
|
CICS + EASO |
Transfer EASO (TI=0) and release CICS |
|
CICS + EAST |
Transfer EAST (TI=0) and release CICS |
|
CICS + EPSO |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
CACS + CIS + EAST |
Transfer CACS as CAS (TI=0), transfer EAST (TI=1) and release CIS |
|
CAS + CICS + EAST |
Transfer CAS (TI=0), transfer EAST (TI=1) and release CICS |
|
CACS + CIS + EPST |
Transfer CACS as CAS (TI=0), release CIS and release EPST |
|
CAS + CICS + EPST |
Transfer CAS (TI=0), release CICS and release EPST |
|
CACS + CICS |
Transfer CACS as CAS (TI=0) and release CICS |
|
CACS + CICS + EAST |
Transfer CACS as CAS (TI=0), transfer EAST (TI=1) and release CICS |
|
CACS + CICS + EPST |
Transfer CACS as CAS (TI=0), release CICS and release EPST |
|
UE supports ALP+PAP only and Network supports at least ALP+PAP or UE supports at least ALP+PAP and Network supports ALP+PAP only |
CACS only |
Transfer CACS as CAS (TI=0) |
CICS only |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
CACS + CIS |
Transfer CACS as CAS (TI=0) and release CIS |
|
CAS + CICS |
Transfer CAS (TI=0) and release CICS |
|
CACS + EAST |
Transfer CACS as CAS (TI=0) and transfer EAST (TI=1) |
|
CACS + EPST |
Transfer CACS as CAS (TI=0) and release EPST |
|
CICS + EASO |
Transfer EASO (TI=0) and release CICS |
|
CICS + EAST |
Transfer EAST (TI=0) and release CICS |
|
CICS + EPSO |
Transfer EPSO (TI=0) and release CICS |
|
CACS + CIS + EAST |
Transfer CACS as CAS (TI=0), transfer EAST (TI=1) and release CIS |
|
CAS + CICS + EAST |
Transfer CAS (TI=0), transfer EAST (TI=1) and release CICS |
|
CACS + CIS + EPST |
Transfer CACS as CAS (TI=0), release CIS and release EPST |
|
CAS + CICS + EPST |
Transfer CAS (TI=0), release CICS and release EPST |
|
CACS + CICS |
Transfer CACS as CAS (TI=0) and release CICS |
|
CACS + CICS + EAST |
Transfer CACS as CAS (TI=0), transfer EAST (TI=1) and release CICS |
|
CACS + CICS + EPST |
Transfer CACS as CAS (TI=0), release CICS and release EPST |
|
UE and Network support MAM+ALP+PAP |
CACS only |
Transfer CACS (NOTE 1) |
CICS only |
Transfer CICS (NOTE 1) |
|
CACS + CIS |
Transfer CACS (NOTE 1) and transfer CIS (TI=1) |
|
CAS + CICS |
Transfer CAS (TI=0) and transfer CICS (NOTE 2) |
|
CACS + EAST |
Transfer CACS (NOTE 1) and transfer EAST (TI=1) |
|
CACS + EPST |
Transfer CACS (NOTE 1) and release EPST |
|
CICS + EASO |
Transfer CICS (NOTE 1) and transfer EASO (TI=1) |
|
CICS + EAST |
Transfer CICS (NOTE 1) and transfer EAST (TI=1) |
|
CICS + EPSO |
Transfer CICS (NOTE 1) and transfer EPSO (TI=1) |
|
CACS + CIS + EAST |
Transfer CACS (NOTE 1), transfer CIS (TI=1), release EAST |
|
CAS + CICS + EAST |
Transfer CAS (TI=0), transfer CICS (NOTE 2), release EAST |
|
CACS + CIS + EPST |
Transfer CACS (NOTE 1), transfer CIS (TI=1), release EPST |
|
CAS + CICS + EPST |
Transfer CAS (TI=0), transfer CICS (NOTE 2), release EAST |
|
CACS + CICS |
Transfer CACS (NOTE 1) transfer CICS as CIS (TI=1) |
|
CACS + CICS + EAST |
Transfer CACS (NOTE 1), transfer CICS as CIS (TI=1) and release EAST |
|
CACS + CICS + EPST |
Transfer CACS (NOTE 1), transfer CICS as CIS (TI=1) and release EPST |
|
UE supports MAM+ ALP only and Network supports at least MAM+ALP or UE supports at least MAM+ ALP and Network supports MAM+ALP only |
CACS only |
Transfer CACS (NOTE 1) |
CICS only |
Transfer CICS (NOTE 1) |
|
CACS + CIS |
Transfer CACS (NOTE 1) and transfer CIS (TI=1) |
|
CAS + CICS |
Transfer CAS (TI=0) and transfer CICS (NOTE 2) |
|
CACS + EAST |
Transfer CACS (NOTE 1) and transfer EAST (TI=1) |
|
CACS + EPST |
Transfer CACS (NOTE 1) and release EPST |
|
CICS + EASO |
Transfer CICS (NOTE 1) and transfer EASO (TI=1) |
|
CICS + EAST |
Transfer CICS (NOTE 1) and transfer EAST (TI=1) |
|
CICS + EPSO |
Transfer CICS (NOTE 1) and release EPSO |
|
CACS + CIS + EAST |
Transfer CACS (NOTE 1), transfer CIS (TI=1), release EAST |
|
CAS + CICS + EAST |
Transfer CAS (TI=0), transfer CICS (NOTE 2), release EAST |
|
CACS + CIS + EPST |
Transfer CACS (NOTE 1), transfer CIS (TI=1), release EPST |
|
CAS + CICS + EPST |
Transfer CAS (TI=0), transfer CICS (NOTE 2), release EAST |
|
CACS + CICS |
Transfer CACS (NOTE 1) and transfer CICS as CIS (TI=1) |
|
CACS + CICS + EAST |
Transfer CACS (NOTE 1), transfer CICS as CIS (TI=1) and release EAST |
|
CACS + CICS + EPST |
Transfer CACS (NOTE 1), transfer CICS as CIS (TI=1) and release EPST |
|
UE has no MAM support and Network supports MAM only or UE supports MAM only and Network has no MAM support |
CACS only |
Transfer CACS as CAS (TI=0) |
CICS only |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
CACS + CIS |
Transfer CACS as CAS (TI=0) and release CIS |
|
CAS + CICS |
Transfer CAS (TI=0) and release CICS |
|
CACS + EAST |
Transfer CACS as CAS (TI=0) and release EAST |
|
CACS + EPST |
||
CICS + EASO |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
CICS + EAST |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
CICS + EPSO |
Send SIP 480 (Temporarily Unavailable) to reject SIP INVITE request due to STN-SR |
|
CACS + CIS + EAST |
Transfer CACS as CAS (TI=0), release CIS and release EAST |
|
CAS + CICS + EAST |
Transfer CAS (TI=0), release CICS and release EAST |
|
CACS + CIS + EPST |
Transfer CACS as CAS (TI=0), release CIS and release EPST |
|
CAS + CICS + EPST |
Transfer CAS (TI=0), release CICS and release EAST |
|
CACS + CICS |
Transfer CACS as CAS (TI=0) and release CICS |
|
CACS + CICS + EAST |
Transfer CACS as CAS (TI=0), release CICS and release EAST |
|
CACS + CICS + EPST |
Transfer CACS as CAS (TI=0), release CICS and release EPST |
|
NOTE 1: TIs are calculated as in the table 9.2.1A-2 with the offsets 0, 2, 3, 4, 5 assigned to the participants in their order in the list of the extracted participants. NOTE 2: TIs are calculated as in the table 9.2.1A-2 with the offsets 0, 1, 2, 3, 4 assigned to the participants in their order in the list of the extracted participants |