Note that this page shows only those active (i.e. not yet completed) WIs where C4 is the sole responsible group.
There may be other active WIs for which this group holds joint responsibility, particularly hierachically higher WIs which comprise WIs from several groups: such WIs are not shown on this page.
| Building Block: SS7 TCAP security Gateway | SEC7-NDS-TCAPsec | Rel-7 |
| Feature or Study Item: PS domain and IMS impacts for supporting IMS Emergency calls (EMC1) | EMC1 | Rel-7 |
| Building Block: Procedures description | Mp-PROCc4 | Rel-7 |
| Feature or Study Item: Mp (MRFC - MRFP) interface | Mp | Rel-7 |
| Building Block: CAMEL Trunk Originated Trigger Detection Points | CamelR7 | Rel-7 |
| Feature or Study Item: Study on Routeing of MT-SMS via the HPLMN | SMS7 | Rel-7 |
| Work task: CT4 aspects of FBI for TISPAN R1 | FBI-TIS1-st3-c4 | Rel-7 |
| Building Block: Stage 3 for Mp (MRFC - MRFP) interface | Mp-St3c4 | Rel-7 |
| Work task: CT4 aspects of EVGCS | EVGCS | Rel-7 |
| Work task: Deleted - CT4 aspects of IVGCS | IVGCS-St3-c4 | Rel-7 |
| Work task: Deleted - CT4 aspets for WLAN-PNA | WLANPNA-st3 | Rel-7 |
| Building Block: CT4 aspects for LCS UEPos-LBS | LCS3-UEPos-LBS | Rel-7 |
| Work task: CT4 PS domain aspects to support IMS Emergency sessions | EMC1-GPRSc4 | Rel-7 |
| Work task: CT4 aspects of Stage 3 for Voice Call Continuity between CS and IMS (incl. I-WLAN) | VCC-St3-c4 | Rel-7 |
| Building Block: Stage 3 CT4 on support of QoS over 3GPP/WLAN Interworking | WLANQOS | Rel-7 |
| Building Block: Emergency Call Enhancements for IP& PS Based Calls – stage 3 | EMC1 | Rel-7 |
| Feature or Study Item: Study on using M2PA in 3GPP network | FS-M2PA | Rel-7 |
| Feature or Study Item: Feasibility Study on the TCAPsec Gateway concept | FS_SEC7-TCAP | Rel-7 |
| Feature or Study Item: Interoperability between VGCS/VBS and A/Gb flexibility | VGCSFlex | Rel-7 |
| Building Block: CT4 aspects of VGCSFlex | VGCSFlex-c4 | Rel-7 |
| Feature or Study Item: Enhancements of VGCS for public authority officials | EVGCS | Rel-7 |
| Building Block: Architecture and protocol aspects | EVGCS | Rel-7 |
| Building Block: WLAN-PNA - Stage 3 | WLANPNA-st3 | Rel-7 |
| Building Block: TISPAN Rel 1 related aspects | FBI-TIS1 | Rel-7 |
| Feature or Study Item: Security enhancements | SEC7 | Rel-7 |
| Feature or Study Item: Multimedia interworking between IMS and CS networks | MIW-IMS | Rel-8 |
| Work task: CT4 part of Stage 3 for CS Fallback in EPS | SAES-CSFB | Rel-8 |
| Building Block: CAT Service in 3GPP CS domain | CAT-3G_CS | Rel-8 |
| Feature or Study Item: Home NodeB / eNodeB | HomeNB | Rel-8 |
| Building Block: Maintenance of TISPAN R2 | MAINT_R2 | Rel-8 |
| Building Block: CT4 part of Network Attachment Subsystem (NASS) Bundled Authentication | NBA-CT4 | Rel-8 |
| Feature or Study Item: Support of Overlap signalling | Overlap | Rel-8 |
| Building Block: Mn interface (MGCF – IM MGW) | MIW-IMS-St3C4 | Rel-8 |
| Feature or Study Item: Study on InterWorking Function between MAP based and Diameter based interfaces | FS_MAP2Diam | Rel-8 |
| Feature or Study Item: Conferencing enhancements for Mp interface | eMp | Rel-8 |
| Building Block: Stage 2 for eMp | eMp | Rel-8 |
| Building Block: Stage 3 for eMp | eMp | Rel-8 |
| Building Block: CT4 part of Enhancement of interworking between MTSI and CS networks | MTSI_eMHI | Rel-8 |
| Work task: CT4 part of Service Level Tracing in IMS | OAM8-Trace | Rel-8 |
| Building Block: Core Network Impacts for A-Interface User Plane over IP | AoIP-CN | Rel-8 |
| Building Block: IMS Restoration Procedures (CT4) | IMS_RP | Rel-8 |
| Feature or Study Item: Encoding formats, transport formats and media description signalling for interworking, QoE, and other enhancements to MTSI-MHI | MTSI_eMHI | Rel-8 |
| Feature or Study Item: Generic Bootstrapping Architecture Push Function | GBAPush | Rel-8 |
| Feature or Study Item: IMS System enhancements for corporate network access | IMS_Corp | Rel-8 |
| Feature or Study Item: Support of (G)MSC-S – (G)MSC-S Nc Interface based on the SIP-I protocol | SIP_Nc | Rel-8 |
| Building Block: SIP-I based circuit-switched core network; Stage 2 | SIP_Nc-St2 | Rel-8 |
| Building Block: Application of SIP-I Protocols to Circuit Switched (CS) core network architecture; Stage 3 | SIP_Nc-St3C4 | Rel-8 |
| Feature or Study Item: Study on IMS Application Server Service Data Descriptions for AS interoperability | FS_IMS_ASIO | Rel-8 |
| Feature or Study Item: Study on Customized Alerting Tone (CAT) solution for voice and video call in CS domain | FS_CAT_VVC_CS | Rel-8 |
| Work task: CT4 Stage 3 for GTP v2 protocol | SAES-SA-FP_LTE-GTP | Rel-8 |
| Work task: Stage 3 for EPC - GPRS | SAES-SA-FP_3GPP | Rel-8 |
| Work task: Stage 3 for Interfaces EPC - non-3GPP IP access | SAES-SA-FP_n3GPP | Rel-8 |
| Work task: Stage 3 for AAA/HSS related | SAES-SA-FP_n3GPP | Rel-8 |
| Work task: Stage 3 for EPC - AAA interface | SAES-SA-FP_n3GPP | Rel-8 |
| Work task: CT4 Stage 3 for protocol between EPCs | SAES-LTE | Rel-8 |
| Work task: Stage 3 for MME - SGSN signalling free protocol | SAES-SA-FP_3GPP | Rel-8 |
| Work task: Stage 3 (CT4) of SAE impact on existing capabilities | SAES | Rel-8 |
| Feature or Study Item: Rel-8 Operations, Administration, Maintenance and Provisioning (OAM&P) | OAM8 | Rel-8 |
| Building Block: Rel-8 Trace Management | OAM8-Trace | Rel-8 |
| Work task: Deleted - CT4 aspects of Stage 3 PNM | PNM | Rel-8 |
| Feature or Study Item: Multimedia Priority Service | PRIOR_EMR | Rel-8 |
| Building Block: IMS Enhancements for Security Requirements in Support of Cable Deployments | PktCbl-Sec | Rel-8 |
| Building Block: Deleted - CT aspects of SAES | SAES-St3 | Rel-8 |
| Feature or Study Item: AoIP (A-interface over IP) | AoIP | Rel-8 |
| Feature or Study Item: 3GPP System Architecture Evolution Specification - Evolved Packet System (non RAN aspects) | SAES | Rel-8 |
| Feature or Study Item: User Data Convergence (UDC) | UDC | Rel-9 |
| Feature or Study Item: IMS – Interconnection Border Control Function (IBCF) – Transition Gateway (TrGW); Ix Interface; Stage 3 | IMS_IBCF | Rel-9 |
| Feature or Study Item: IMS Application Level Gateway Control Function (ALGCF) – IMS Access Media Gateway (IMA-MGW); Iq Interface; Stage 2 and Stage 3 | IMS_AGCF | Rel-9 |
| Feature or Study Item: Public Warning System | PWS | Rel-9 |
| Building Block: CT4 part of IMS – Interconnection Border Control Function (IBCF) – Transition Gateway (TrGW); Ix Interface; Stage 3 | IMS_IBCF | Rel-9 |
| Work task: User Data Convergence (UDC) Technical Realization (Stage 2) | UDC-CN | Rel-9 |
| Feature or Study Item: LCS for LTE and EPS | LCS_LTE_EPS | Rel-9 |
| Building Block: Stage 2/3 for User Data Convergence (UDC) Technical Realization | UDC-CN | Rel-9 |
| Work task: CT4 part of CN aspects of Enabling Coder Selection and Rate Adaptation for UTRAN and E-UTRAN for Load Adaptive Applications | ECSRA_LAA-CN | Rel-10 |
| Work task: CT4 part on Stage 3 on enhancements for Multimedia Priority Service | eMPS-CN | Rel-10 |
| Work task: CT4 part of Stage 3 for S2b Mobility based on GTP | SMOG-St3 | Rel-10 |
| Building Block: CN aspects of Enabling Coder Selection and Rate Adaptation for UTRAN and E-UTRAN for Load Adaptive Applications | ECSRA_LAA-CN | Rel-10 |
| Building Block: Stage 3 on enhancements for Multimedia Priority Service | eMPS-CN | Rel-10 |
| Building Block: Stage 3 for S2b Mobility based on GTP | SMOG-St3 | Rel-10 |
| Building Block: Stage 2/3 for CN aspects of Local Call Local Switch | LCLS-CN | Rel-10 |
| Feature or Study Item: CN aspects of Local Call Local Switch | LCLS-CN | Rel-10 |
| Building Block: TR on CN aspects of Local Call Local Switch | LCLS-CN | Rel-10 |
| Feature or Study Item: Multi Access PDN Connectivity | MAPCON | Rel-10 |
| Feature or Study Item: Network Improvements for Machine-Type Communications | NIMTC | Rel-10 |
| Building Block: CN part of Stage 3 for Network Improvements for Machine-Type Communications | NIMTC-CN | Rel-10 |
| Work task: Stage 3 for SIPTO for macro networks | SIPTO | Rel-10 |
| Work task: Stage 3 for Local IP Access | LIPA | Rel-10 |
| Building Block: Stage 3 for Optimal Media Routing | OMR | Rel-10 |
| Feature or Study Item: Deleted - Study on Interworking Proxy between GTP based and PMIP based interfaces | FS_GTP-MIP-IW | Rel-10 |
| Feature or Study Item: Relays for LTE | LTE_Relay | Rel-10 |
| Feature or Study Item: Enhancements for Multimedia Priority Service | eMPS | Rel-10 |
| Feature or Study Item: Study on EPC Nodes Restoration | FS_EPC_NR | Rel-11 |
| Feature or Study Item: System Improvements to Machine-Type Communications | SIMTC | Rel-11 |
| Feature or Study Item: LOcation-Based Selection of gaTEways foR WLAN | LOBSTER | Rel-11 |
| Building Block: CT4 part of enhanced Nodes Restoration for EPC | eNR_EPC | Rel-11 |
| Building Block: CT4 part of Reference Location Information (Stage 3) | RLI | Rel-11 |
| Feature or Study Item: Service Identification for RRC Improvements in GERAN (Stage 2/3) | SIRIG | Rel-11 |
| Building Block: Stage 2/3 for CS aspects for SIMTC | SIMTC-CS | Rel-11 |
| Building Block: CT4 part of IMS Operator Determined Call Barring | IODB | Rel-11 |
| Building Block: CT4 part of Enhanced T.38 FAX support | MMTel_T.38_FAX | Rel-11 |
| Work task: CT4 part of CT aspects of Network-provided Location information for IMS | NWK-PL2IMS-CT | Rel-11 |
| Building Block: Stage 2/3 for SMS in MME architecture option and related PS-only service subscription | SIMTC-PS_Only | Rel-11 |
| Work task: TR on Stage 3 BB I for BBAI; Home (e)Node B – Security Gateway Interface | BBAI_BBI-CT | Rel-11 |
| Work task: CT4 part of CT aspects of LOcation-Based Selection of gaTEways foR WLAN | LOBSTER-CT | Rel-11 |
| Work task: CT4 part of CN aspects of Mobility based On GTP & PMIPv6 for WLAN access to EPC | SaMOG_WLAN-CN | Rel-11 |
| Work task: CT4 part of Core Network aspects of Anonymous Call Rejection in the CS domain (Stage 2/3) | ACR_CS-CN | Rel-11 |
| Work task: CT4 part of Stage 3 BB1: Reachability Aspects of SIMTC | SIMTC-ReachCSPS | Rel-11 |
| Work task: CT4 part of Stage 3 BB I: BBF interworking with home routed traffic for WLAN and H(e)NB | BBAI_BBI-CT | Rel-11 |
| Work task: CT4 part of Stage 3 BB II: BBF interworking with offload in access network for WLAN and for H(e)NB | BBAI_BBII-CT | Rel-11 |
| Work task: CT4 part for Single Radio Voice Call Continuity from UTRAN/GERAN to E-UTRAN/HSPA | rSRVCC-CT | Rel-11 |
| Building Block: CT aspects of WLAN/3GPP Radio Interworking (Stage 2/3) | UTRA_LTE_WLAN_interw-CT | Rel-12 |
| Building Block: CT aspects of Group Communication System Enablers for LTE | GCSE_LTE-CT | Rel-12 |
| Building Block: CT4 part of Diameter Overload Control Mechanisms | DOCME | Rel-12 |
| Work task: CT4 part of CT impacts of codec for Enhanced Voice Services | EVS_codec-CT | Rel-12 |
| Feature or Study Item: Enhanced S2a Mobility Over trusted WLAN access to EPC | eSaMOG | Rel-12 |
| Feature or Study Item: Network-provided Location information for IMS Trusted WLAN Access Network (TWAN) case | NETLOC_TWAN | Rel-12 |
| Work task: CT4 part of Common for HSS & PCRF solutions | PCSCF_RES | Rel-12 |
| Work task: Stage 3 for BB1: Small Data and Device Triggering Enhancements | MTCe-SDDTE-CT | Rel-12 |
| Feature or Study Item: Interactive Connectivity Establishment (ICE, IETF RFC 5245) impacts on IMS H.248 profiles | ICEH248 | Rel-12 |
| Building Block: CT aspects of Web Real Time Communication (WebRTC) Access to IMS | IMS_WebRTC-CT | Rel-12 |
| Building Block: CT aspects of Core Network Overload – User Location Information reporting improvements | CNO_ULI-CT | Rel-12 |
| Feature or Study Item: Support of ALT-C attribute | ALTC | Rel-12 |
| Work task: CT4 part of Network-provided Location information for IMS Trusted WLAN Access Network (TWAN) case | NETLOC_TWAN-CT | Rel-12 |
| Work task: CT4 part of CT aspects of Web Real Time Communication (WebRTC) Access to IMS | IMS_WebRTC-CT4 | Rel-12 |
| Work task: CT4 part of CT aspects of Core Network Overload – User Location Information reporting improvements | CNO_ULI-CT | Rel-12 |
| Work task: TR on Extended IMS media plane security features and TCP related NAT traversal support; IMS H.248 profiles aspects | eMEDIASEC-CT | Rel-12 |
| Work task: CT4 part of CT aspects of Coordination of Video Orientation | CVO-CT | Rel-12 |
| Building Block: CT4 part of Signalling of Image Size | SIS_CT | Rel-12 |
| Building Block: CT aspects of Coordination of Video Orientation | CVO-CT | Rel-12 |
| Building Block: CT aspects of End-to-End Multimedia Telephony Service for IMS (MTSI) extensions | E2EMTSI-CT | Rel-12 |
| Feature or Study Item: CT aspects of Signalling of Image Size (Stage 2/3) | SIS_CT | Rel-12 |
| Building Block: Deleted - CT aspects of IMS registration control | IMS_RegCon-CT | Rel-12 |
| Building Block: CT4 part of eMBMS restoration procedures | eMBMS_Rest | Rel-12 |
| Work task: CT4 part of Stage 3 for SMS submit and delivery without MSISDN in IMS | SMSMI-CT | Rel-12 |
| Feature or Study Item: Group Communication System Enablers for LTE | GCSE_LTE | Rel-12 |
| Feature or Study Item: Policy and Charging Control for supporting fixed broadband access networks | P4C | Rel-12 |
| Feature or Study Item: Coordination of Video Orientation | CVO | Rel-12 |
| Feature or Study Item: Extended IMS media plane security features | eMEDIASEC | Rel-12 |
| Work task: CT4 part of CT aspects of Extended IMS media plane security features | eMEDIASEC-CT | Rel-12 |
| Feature or Study Item: Reporting Enhancements in Warning Message Delivery (Stage 2/3) | REP_WMD | Rel-12 |
| Building Block: CT4 part of Reporting Enhancements in Warning Message Delivery (Stage 2/3) | REP_WMD-CT4 | Rel-12 |
| Feature or Study Item: IM-SSF Application Server Service Data Descriptions (Stage 2/3) | IMS_SSFDD | Rel-12 |
| Building Block: Stage 3 for IM-SSF Application Server Service Data Descriptions | IMS_SSFDD | Rel-12 |
| Feature or Study Item: Diameter based interface between SGSN and SMS central functions (Stage 2/3) | Dia_SGSN_SMS | Rel-12 |
| Feature or Study Item: Diameter based interface between SGSN-GMLC (Stage 3) | Dia_SGSN_GMLC | Rel-12 |
| Feature or Study Item: Study on Diameter Overload Control Mechanisms | FS_DOCME | Rel-12 |
| Building Block: Stage 3 for Diameter based interface between SGSN and SMS central functions | Dia_SGSN_SMS | Rel-12 |
| Feature or Study Item: LIPA Mobility and SIPTO at the Local Network | LIMONET | Rel-12 |
| Building Block: CT4 aspects of Mobile Equipment Identity signalling over WLAN | MEI_WLAN | Rel-13 |
| Building Block: CT4 aspects of Controlling IMS Media Plane with SDP Capability | SDPCN_IMS | Rel-13 |
| Feature or Study Item: User Plane Congestion management | UPCON | Rel-13 |
| Work task: CT4 aspects for Non-IP for Cellular Internet of Things for EC-EGPRS | NonIP_GPRS-CT | Rel-14 |
| Building Block: deleted -CT4 aspects of MTSI Extension on Multi-stream | MMCMH-CT | Rel-14 |
| Feature or Study Item: SCC AS Restoration | SCCAS_RES | Rel-14 |
| Work task: CT4 aspects of MMCMH_Enh | MMCMH_Enh-CT | Rel-14 |
| Work task: CT4 aspects of EWE | EWE-CT | Rel-14 |
| Feature or Study Item: Shared Subscription Data Update | eSDU | Rel-14 |
| Building Block: CT4 Aspect of H.248 Aspects of WebRTC Data Channel on IMS Access Gateway | WebRTCH248DC | Rel-13 |
| Building Block: CT aspects of EVS in 3G Circuit-Switched Networks | EVSoCS-CT | Rel-13 |
| Building Block: CT4 aspects of Enhanced P-CSCF discovery using signalling for access to EPC via WLAN | ePCSCF_WLAN | Rel-13 |
| Building Block: Study on Diameter Load Control Mechanisms | FS_DLoCME | Rel-13 |
| Feature or Study Item: Shared Data Update for Multiple Subscriber | SHARED_SubData_UPD | Rel-13 |
| Feature or Study Item: Study on EPC Signalling Improvement for Race Scenarios | FS_EPC_SIG_RACE | Rel-13 |
| Feature or Study Item: P-CSCF Restoration Enhancements with WLAN | PCSCF_RES_WLAN | Rel-13 |
| Building Block: CT4 aspects of Warning Status Report in EPS | WSR_EPS | Rel-13 |
| Work task: CT4 part of CT aspects of User Plane Congestion Management for BB1 | UPCON-DOTCON-CT | Rel-13 |
| Work task: CT4 part of CT aspects of voice over E-UTRAN Paging Policy Differentiation | voE_UTRAN_PPD-CT | Rel-13 |
| Building Block: CT aspects of voice over E-UTRAN Paging Policy Differentiation | voE_UTRAN_PPD-CT | Rel-13 |
| Feature or Study Item: Support of EVS in 3G Circuit-Switched networks | EVSoCS | Rel-13 |
| Feature or Study Item: QoS End-to-end Multimedia Telephony Service for IMS (MTSI) extensions (Stage 3) | QOSE2EMTSI | Rel-13 |
| Feature or Study Item: voice over E-UTRAN Paging Policy Differentiation | voE_UTRAN_PPD | Rel-13 |
| Work task: CT4 aspects of Enhancements for Mission Critical Push To Talk | MCImp-eMCPTT-CT | Rel-14 |
| Work task: CT4 aspects of MCData | MCImp-MCDATA-CT | Rel-14 |
| Work task: CT4 aspects 3 of MCVideo | MCImp-MCVIDEO-CT | Rel-14 |
| Work task: CT4 aspects of extended architecture enhancements for Cellular Internet of Things | CIoT_Ext-CT | Rel-14 |
| Feature or Study Item: EPC Signalling Improvements for race scenarios | EPC_SIG_RACE | Rel-13 |
| Feature or Study Item: Study on Impacts of the Diameter Base Protocol Specification Update | FS_DBPU | Rel-13 |
| Work task: CT4 aspects for Dedicated Core Networks CT aspects | DECOR-CT | Rel-13 |
| Work task: CT4 aspects for Enhancements to WebRTC interoperability | eWebRTCi-CT | Rel-13 |
| Work task: CT4 aspects for MCPTT protocol aspects | MCPTT-CT | Rel-13 |
| Work task: CT4 aspects of extended DRX cycle | eDRX-CT | Rel-13 |
| Work task: CT4 aspects of Support of Emergency services over WLAN – phase 1 | SEW1-CT | Rel-13 |
| Building Block: CT4 aspects for EPC Signalling Improvements for race scenarios | EPC_SIG_RACE | Rel-13 |
| Work task: CT4 aspects of MBMS enhancements | MBMS_enh-CT | Rel-13 |
| Feature or Study Item: Diameter Message Priority | DiaPri | Rel-13 |
| Building Block: CT4 aspects of DiaPri | DiaPri | Rel-13 |
| Building Block: CT aspects of Indoor Positionning | UTRA_LTE_iPos_enh-CT | Rel-13 |
| Work task: CT4 aspects of CIoT | CIoT-CT | Rel-13 |
| Work task: CT4 aspects of Indoor Positionning | UTRA_LTE_iPos_enh-CT | Rel-13 |
| Feature or Study Item: Support of Real-time Transport Protocol (RTP) / Real-time Transport Control Protocol (RTCP) multiplexing (signalling) in IMS | RTCP_MUX | Rel-13 |
| Building Block: CT4 part of Support of RTP / RTCP multiplexing (signalling) in IMS | RTCP_MUX | Rel-13 |
| Work task: CT4 aspects of system architecture enhancements for TV service | AE_enTV-CT | Rel-14 |
| Work task: CT4 aspects of Diameter Base Protocol Specification Update | DBPU | Rel-14 |
| Work task: Stage 3 CN aspects of SIPTO at the Local Network | LIMONET-SIPTO | Rel-12 |
| Work task: Deleted - Stage 3 CN aspects of LIPA Mobility | LIMONET-LIPA-del2 | Rel-12 |
| Feature or Study Item: Short Message Service (SMS) submit and delivery without MSISDN in IMS | SMSMI | Rel-12 |
| Building Block: CT4 aspects of P-CSCF Restoration Enhancements with WLAN | PCSCF_RES_WLAN | Rel-13 |
| Feature or Study Item: Warning Status Report in EPS | WSR_EPS | Rel-13 |
| Building Block: CT Aspects of QoS End-to-End MTSI Extensions | QOSE2EMTSI-CT | Rel-13 |
| Work task: CT4 Aspects of QoS End-to-End MTSI Extensions | QOSE2EMTSI-CT | Rel-13 |
| Feature or Study Item: Codec for Enhanced Voice Services | EVS_codec | Rel-12 |
| Work task: CT4 aspects of enhancements to Proximity-based | eProSe-Ext-CT | Rel-13 |
| Building Block: Monitoring Enhancements CT aspects | MONTE-CT | Rel-13 |
| Feature or Study Item: Mobile Equipment Identity signalling over WLAN | MEI_WLAN | Rel-13 |
| Feature or Study Item: Study on SCC AS Restoration | FS_SCCAS_RES | Rel-13 |
| Feature or Study Item: Controlling IMS Media Plane with SDP Capability | SDPCN_IMS | Rel-13 |
| Building Block: Stage 3 for Enhanced S2a Mobility Over trusted WLAN access to EPC | eSaMOG-St3 | Rel-12 |
| Work task: CT4 part of IMS Telepresence (Stage 2/3) | IMS_TELEP | Rel-12 |
| Work task: Stage 3 for BB1: Policy and Charging Control for supporting traffic from fixed terminals and NSWO traffic from 3GPP UEs in fixed broadband access networks | P4C-F-CT3 | Rel-12 |
| Building Block: CT aspects of Optimizations to Support High Latency | HLcom-CT | Rel-13 |
| Building Block: CT aspects of Group based Enhancements | GROUPE-CT | Rel-13 |
| Building Block: CT Aspects of Video Enhancements by Region-Of-Interest information signalling | ROI-CT | Rel-13 |
| Feature or Study Item: Study on S6a/S6d Shared Data Update | FS_eSDU | Rel-13 |
| Work task: CT4 aspects of IP Flow Mobility support for S2a and S2b Interfaces | NBIFOM-CT | Rel-13 |
| Work task: CT4 aspects of Architecture Enhancements for Service capability Exposure | AESE-CT | Rel-13 |
| Work task: CT4 aspects of Monitoring Enhancements | MONTE-CT | Rel-13 |
| Work task: CT4 aspects of Group based Enhancements | GROUPE-CT | Rel-13 |
| Work task: CT4 Aspects of Video Enhancements by Region-Of-Interest information signalling | ROI-CT | Rel-13 |
| Work task: CT4 aspects of EVS in 3G Circuit-Switched Networks | EVSoCS-CT | Rel-13 |
| Feature or Study Item: H.248 Aspects of WebRTC Data Channel on IMS Access Gateway | WebRTCH248DC | Rel-13 |
| Work task: Deleted - CT4 aspects of CT aspects of IMS registration control (Stage 3) | IMS_RegCon-CT4 | Rel-12 |
| Work task: CT4 part of CT aspects of End-to-End Multimedia Telephony Service for IMS (MTSI) extensions | E2EMTSI-CT | Rel-12 |
| Feature or Study Item: GPRS Tunnelling Protocol for the Control plane (GTP-C) Overload Control Mechanisms | GOCMe | Rel-12 |
| Building Block: CT aspects for LTE-HRPD (High Rate Packet Data in 3GPP2) inter-RAT SON (Stage 3) | LTE_HRPD_SON-CT | Rel-12 |
| Feature or Study Item: Proxy Call Session Control Function (P-CSCF) restoration enhancements (Stage 2/3) | PCSCF_RES | Rel-12 |
| Building Block: CT4 aspects of MCPTTProtoc1 | MCPTTProtoc1 | Rel-14 |
| Work task: CT4 aspects of eDecor | eDecor-CT | Rel-14 |
| Work task: CT4 aspects of SEW2 | SEW2-CT | Rel-14 |
| Work task: CT4 aspects of V2X Services | V2X-CT | Rel-14 |
| Work task: CT4 Aspect of AULC | AULC-CT | Rel-14 |
| Work task: CT4 aspects for CUPS | CUPS-CT | Rel-14 |
| Building Block: CT4 aspects of Diameter Load Control Mechanism | DLoCMe | Rel-14 |
| Work task: CT4 aspects of ERP | ERP-CT | Rel-14 |
| Feature or Study Item: LTE-HRPD (High Rate Packet Data in 3GPP2) inter-RAT SON | LTE_HRPD_SON | Rel-12 |
| Feature or Study Item: eMBMS restoration procedures | eMBMS_Rest | Rel-12 |
| Building Block: Stage 3 for SMS submit and delivery without MSISDN in IMS | SMSMI-CT | Rel-12 |
| Work task: Deleted - CT4 part of CN aspects of LIPA Mobility | LIMONET-LIPA-del4 | Rel-12 |
| Work task: CT4 part of Stage 3 CN aspects of SIPTO at the Local Network | LIMONET-SIPTO-CT4 | Rel-12 |
| Feature or Study Item: IMS-based Telepresence | IMS_TELEP | Rel-12 |
| Work task: CT4 part of CT aspects of Proximity-based Services | ProSe-CT | Rel-12 |
| Feature or Study Item: Diameter Overload Control Mechanisms | DOCME | Rel-12 |
| Work task: CT4 part of Group Communication System Enablers for LTE | GCSE_LTE-CT | Rel-12 |
| Building Block: HSS based solution | PCSCF_RES | Rel-12 |
| Building Block: Common for HSS & PCRF solutions | PCSCF_RES | Rel-12 |
| Work task: CT4 part of CT aspects of WLAN/3GPP Radio Interworking (Stage 2/3) | UTRA_LTE_WLAN_interw-CT | Rel-12 |
| Building Block: CT impacts of codec for Enhanced Voice Services | EVS_codec-CT | Rel-12 |
| Building Block: CT aspects of Dual connectivity for LTE | LTE_SC_enh_dualC-CT | Rel-12 |
| Work task: CT4 part of Stage 3 for Enhanced S2a Mobility Over trusted WLAN access to EPC | eSaMOG-St3 | Rel-12 |
| Work task: CT4 part of HSS based solution | PCSCF_RES | Rel-12 |
| Feature or Study Item: Dual connectivity for LTE | LTE_SC_enh_dualC | Rel-12 |
| Feature or Study Item: Deleted - IMS Registration Control | IMS_RegCon | Rel-12 |
| Feature or Study Item: Study on Shared Data Update for Multiple Subscribers | FS_SHARED_SubData_UPD | Rel-12 |
| Building Block: CT aspects of Network-provided Location information for IMS Trusted WLAN Access Network (TWAN) case (Stage 3) | NETLOC_TWAN-CT | Rel-12 |
| Work task: CT4 part of Stage 3 for BB1: Policy and Charging Control for supporting traffic from fixed terminals and NSWO traffic from 3GPP UEs in fixed broadband access networks | P4C-F-CT3 | Rel-12 |
| Feature or Study Item: WLAN/3GPP Radio Interworking | UTRA_LTE_WLAN_interw | Rel-12 |
| Work task: Deleted - CT4 part of Stage 3 for BB3: UE Power Consumptions Optimizations (UEPCOP) | MTCe-UEPCOP-CT4 | Rel-12 |
| Feature or Study Item: Anonymous Call Rejection in the CS domain | ACR_CS | Rel-11 |
| Work task: CT4 aspects of Single Radio Video Call Continuity for 3G-CS | vSRVCC-CT | Rel-11 |
| Feature or Study Item: Single Radio Voice Call Continuity from UTRAN/GERAN to E-UTRAN/HSPA | rSRVCC | Rel-11 |
| Building Block: CN Stage 3 for Full Support of Multi-Operator Core Network by GERAN | Full_MOCN-GERAN | Rel-11 |
| Building Block: BB1: Stage 3 (CS+PS) Reachability Aspects of SIMTC | SIMTC-ReachCSPS | Rel-11 |
| Building Block: Core Network aspects of Anonymous Call Rejection in the CS domain | ACR_CS-CN | Rel-11 |
| Building Block: Stage 3 BB I - Core Network impacts: BBF interworking with home routed traffic for WLAN and H(e)NB | BBAI_BBI-CT | Rel-11 |
| Building Block: Stage 3 BB II - Core Network impacts: BBF interworking with offload in access network for WLAN and for H(e)NB | BBAI_BBII-CT | Rel-11 |
| Work task: CT4 part of Stage 3 for BB1: Small Data and Device Triggering Enhancement | MTCe-SDDTE-CT | Rel-12 |
| Building Block: CT4 part of ICE impacts on IMS H.248 profiles (Stage 2/3) | ICEH248 | Rel-12 |
| Work task: CT4 part of CN Stage 3 for Full Support of Multi-Operator Core Network by GERAN | Full_MOCN-GERAN | Rel-11 |
| Feature or Study Item: PS Additional Number (Stage 3) | PSAN | Rel-11 |
| Feature or Study Item: Generic IMS User Group Over Sh | GenUG_Sh | Rel-11 |
| Work task: CT4 part of Stage 2/3 for SMS in MME architecture option and related PS-only service subscription | SIMTC-PS_Only | Rel-11 |
| Feature or Study Item: IMS Operator Determined Call Barring | IODB | Rel-11 |
| Feature or Study Item: Enhanced T.38 FAX support (Stage 3) | MMTel_T.38_FAX | Rel-11 |
| Building Block: CT aspects of Network-provided Location information for IMS (Stage 3) | NWK-PL2IMS-CT | Rel-11 |
| Building Block: TR on Proxy Call Session Control Function (P-CSCF) restoration enhancements | PCSCF_RES | Rel-12 |
| Feature or Study Item: Core Network Overload - User Location Information reporting improvement | CNO_ULI | Rel-12 |
| Building Block: Deleted - TR Study on enhancement of protocols for SMS service over SGs | PROTOC_SMS_SGs | Rel-11 |
| Building Block: CT4 part of Enhancements for Multimedia Priority Service (MPS) – Gateway Control Priority | eMPS_Gateway | Rel-11 |
| Work task: CT4 part of CN aspects of Service Identification for RRC Improvements in GERAN | SIRIG | Rel-11 |
| Building Block: Stage 3 for GBA extensions for re-use of SIP Digest credentials | GBA-ext-St3 | Rel-11 |
| Building Block: Deleted - CT4 part of Enhancement of the Protocols for SMS over SGs | PROTOC_SMS_SGs | Rel-11 |
| Work task: CT4 part of Stage 3 for GBA extensions for re-use of SIP Digest credentials | GBA-ext-St3 | Rel-11 |
| Feature or Study Item: S2a Mobility based On GTP and WLAN access to EPC | SaMOG_WLAN | Rel-11 |
| Building Block: CT aspects of VPLMN Autonomous CSG Roaming | VCSG-St3 | Rel-11 |
| Work task: Deleted - Stage 2 CS aspects for SIMTC | SIMTC-CS | Rel-11 |
| Work task: Management of UE based network performance measurements | OAM-PM-UE | Rel-10 |
| Building Block: CT4 part of Support of ALT-C attribute | ALTC | Rel-12 |
| Feature or Study Item: Local IP Access and Selected Internet IP Traffic Offload | LIPA_SIPTO | Rel-10 |
| Building Block: Stage 2/3 for SIPTO for macro networks | SIPTO | Rel-10 |
| Feature or Study Item: Enabling Coder Selection and Rate Adaptation for UTRAN and E-UTRAN for Load Adaptive Applications | ECSRA_LAA | Rel-10 |
| Building Block: Stage 2/3 for Local IP Access | LIPA | Rel-10 |
| Building Block: CT aspects of LOcation-Based Selection of gaTEways foR WLAN | LOBSTER-CT | Rel-11 |
| Building Block: CN aspects of Mobility based On GTP & PMIPv6 for WLAN access to EPC | SaMOG_WLAN-CN | Rel-11 |
| Feature or Study Item: Generic Bootstrapping Architecture (GBA) extensions for re-use of SIP Digest credentials | GBA-ext | Rel-11 |
| Feature or Study Item: Deleted - Enhancement of the Protocols for SMS over SGs (Stage 3) | PROTOC_SMS_SGs | Rel-11 |
| Feature or Study Item: Enhancements for Multimedia Priority Service (MPS) – Gateway Control Priority | eMPS_Gateway | Rel-11 |
| Building Block: CN aspects of Service Identification for RRC Improvements in GERAN | SIRIG | Rel-11 |
| Feature or Study Item: Support for BroadBand Forum Accesses Interworking | BBAI | Rel-11 |
| Feature or Study Item: User Data Convergence - Data Model | UDC_DM | Rel-11 |
| Building Block: CT aspects for Single Radio Voice Call Continuity from UTRAN/GERAN to E-UTRAN/HSPA (Stage 3) | rSRVCC-CT | Rel-11 |
| Building Block: Deleted - CT4 part of GCSMSC and GCR Redundancy for VGCS/VBS | RT_VGCS_Red | Rel-11 |
| Feature or Study Item: Single Radio Video Call Continuity for 3G-CS | vSRVCC | Rel-11 |
| Feature or Study Item: VPLMN Autonomous CSG Roaming | VCSG | Rel-11 |
| Building Block: User Data Convergence (UDC) Data Model | UDC_DM | Rel-11 |
| Building Block: CT4 aspects of Multiple PDN Connection to the Same APN for PMIP-based Interfaces | MUPSAP | Rel-9 |
| Work task: CT4 aspects of IMS Media Plane Security | MEDIASEC_CORE | Rel-9 |
| Building Block: CT4 aspects of VAS4SMS Interface and Signalling Flow | VAS4SMS | Rel-9 |
| Building Block: Single Radio Voice Call Continuity (SRVCC) support for IMS Emergency Calls | IMS_EMER_GPRS_EPS-SRVCC | Rel-9 |
| Building Block: BB1: Small Data and Device Triggering Enhancements (SDDTE) | MTCe-SDDTE | Rel-12 |
| Building Block: BB1: Policy and Charging Control for supporting traffic from fixed terminals and NSWO (Non Seamless WLAN Offload) traffic from 3GPP UEs in fixed broadband access networks (P4C-F) | P4C-F | Rel-12 |
| Building Block: CT part for IMS Telepresence (Stage 2/3) | IMS_TELEP | Rel-12 |
| Building Block: CT aspects of Extended IMS media plane security features (Stage 2/3) | eMEDIASEC-CT | Rel-12 |
| Feature or Study Item: Multiple PDN Connection to the Same APN for PMIP-based Interfaces | MUPSAP | Rel-9 |
| Feature or Study Item: IMS Media Plane Security | MEDIASEC | Rel-9 |
| Feature or Study Item: Completion of IMS Restoration Procedures | eIMS_RP | Rel-9 |
| Building Block: CT4 aspects of Completion of IMS Restoration Procedures | eIMS_RP | Rel-9 |
| Work task: CT4 aspects of Control Plane LCS in the EPC | LCS_EPS-CPS | Rel-9 |
| Building Block: CT4 aspects of MBMS support in EPS (Stage 3) | MBMS_EPS | Rel-9 |
| Work task: CT4 aspects of SRVCC support for IMS Emergency Calls | IMS_EMER_GPRS_EPS-SRVCC | Rel-9 |
| Building Block: Stage 3 for Public Warning System | PWS-St3 | Rel-9 |
| Work task: CT4 aspects of Stage 3 for Public Warning System | PWS-St3 | Rel-9 |
| Building Block: Stage 3 for IMS Emergency Calls over GPRS and EPS | IMS_EMER_GPRS_EPS | Rel-9 |
| Work task: CT4 aspects - Stage 3 for IMS Emergency Calls over GPRS and EPS | IMS_EMER_GPRS_EPSC4 | Rel-9 |
| Feature or Study Item: 128 bit encryption for GSM and GPRS | A5/4-GEA4 | Rel-9 |
| Building Block: Deleted - CT4 part of Network Domain Security (NDS) enhancements to support backhaul security | NDS_Backhaul | Rel-9 |
| Building Block: CT4 part of 128 bit encryption for GSM and GPRS | A5/4-GEA4 | Rel-9 |
| Building Block: TR on User Data Convergence (UDC) Data Model | UDC_DM | Rel-11 |
| Feature or Study Item: Network-provided Location information for IMS (NETLOC) | NWK-PL2IMS | Rel-11 |
| Feature or Study Item: EPC Node Restoration without Idle mode Signalling Reduction (ISR) activated | EPC_NR | Rel-10 |
| Feature or Study Item: Mobile Terminating Roaming Forwarding with pre-paging | MTRF | Rel-10 |
| Building Block: Core Network Impacts for Relay Nodes | LTE_Relay-CN | Rel-10 |
| Feature or Study Item: EPC Node Restoration with Idle mode Signalling Reduction (ISR) activated | EPC_NR_ISR | Rel-10 |
| Feature or Study Item: S2b Mobility based on GTP | SMOG | Rel-10 |
| Work task: CT4 part of Stage 3 for SIPTO for macro networks | SIPTO | Rel-10 |
| Work task: CT4 part of Stage 3 for Local IP Access | LIPA | Rel-10 |
| Feature or Study Item: Enhanced User Data Convergence (UDC) Model | eUDC | Rel-10 |
| Feature or Study Item: Study on User Data Convergence (UDC) evolution | FS_UDCe | Rel-10 |
| Building Block: CN aspects of Single Radio Video Call Continuity for 3G-CS | vSRVCC-CT | Rel-11 |
| Feature or Study Item: enhanced Nodes Restoration for EPC (Stage 2/3) | eNR_EPC | Rel-11 |
| Feature or Study Item: Reference Location Information (Stage 3) | RLI | Rel-11 |
| Work task: Stage 3 for EPC to UTRAN | SAES-SA-FP_3GPP | Rel-8 |
| Work task: Stage 3 for EPC to 3GPP2 | SAES-SA-FP_3GPP | Rel-8 |
| Building Block: Domain Name System Procedures for Evolved Packet System (DEPS) | SAES-DEPS | Rel-8 |
| Building Block: Stage 3 for ICSRA – Protocol, Addressing, Subscriber Data | ICSRA | Rel-8 |
| Work task: CT4 part of Core Network Impacts for A-Interface User Plane over IP | AoIP-CN | Rel-8 |
| Feature or Study Item: IMS Application Server Service Data Descriptions for AS interoperability | IMS_ASIO | Rel-8 |
| Work task: Mobile IPv4 (MIPv4) based Mobility protocols | SAES-SA-FP_LTE-IETF | Rel-8 |
| Work task: MME to MSC interface for SRVCC | SAES-SRVCC | Rel-8 |
| Building Block: InterWorking Function (IWF) between MAP based and Diameter based interfaces | SAES-MAP2Diam | Rel-8 |
| Work task: CT4 aspects - Stage 3 for ICSRA | ICSRA | Rel-8 |
| Building Block: Stage 3 CIMS_3GPP2 | REDOC_3GPP2 | Rel-8 |
| Building Block: CT4 part of Stage 3 for IMS-Sec | IMS-Sec | Rel-8 |
| Building Block: CT4 part of GBAPush | GBAPush | Rel-8 |
| Feature or Study Item: IMS Restoration Procedures | IMS_RP | Rel-8 |
| Work task: CT4 part of Stage 3 for Network Improvements for Machine-Type Communications | NIMTC-CN | Rel-10 |
| Work task: Deleted - CT4 part of Stage 3 for Optimal Media Routeing | OMR | Rel-10 |
| Feature or Study Item: Study on IMS Restoration Procedures | FS_IMS_RP | Rel-8 |
| Work task: Deleted - CT4 aspects of SAES | SAES | Rel-8 |
| Building Block: SAE for LTE access | SAES-LTE | Rel-8 |
| Building Block: SAE for Interoperation between LTE and legacy cellular PS accesses | SAES-SA-FP_3GPP | Rel-8 |
| Building Block: SAE for support for non-3GPP accesses | SAES-SA-FP_n3GPP | Rel-8 |
| Feature or Study Item: Earthquake and Tsunami Warning System | ETWS | Rel-8 |
| Feature or Study Item: IMS Multimedia Telephony and Supplementary Services | IMSTSS | Rel-8 |
| Building Block: General aspects of IMS Sup Services | IMSSS-Gal | Rel-8 |
| Feature or Study Item: Security Enhancements for IMS | IMS-Sec | Rel-8 |
| Building Block: CT aspects of Multi Access PDN Connectivity | MAPCON-St3 | Rel-10 |
| Feature or Study Item: Single Radio Voice Call Continuity (SRVCC) enhancements (Stage 3) | eSRVCC | Rel-10 |
| Feature or Study Item: PCRF failure and restoration | PCRF_FR | Rel-10 |
| Building Block: CT4 part of Stage 3 for SRVCC enhancements | eSRVCC | Rel-10 |
| Work task: CT4 aspects of Multi Access PDN Connectivity | MAPCON-St3 | Rel-10 |
| Building Block: CT4 part of PCRF failure and restoration | PCRF_FR | Rel-10 |
| Building Block: High level and common (for all accesses) functions | EPS-ComF | Rel-8 |
| Work task: Stage 3 for interfaces within EPC | SAES-SA-FP_n3GPP | Rel-8 |
| Work task: CT4 Stage 3 for PMIP protocol within EPC | SAES-SA-FP_LTE-IETF | Rel-8 |
| Building Block: CT4 part of Stage 3 for PRIOR | PRIOR_EMR | Rel-8 |
| Feature or Study Item: IMS Centralized Service control | ICSRA | Rel-8 |
| Feature or Study Item: IMS Enhancements for support of Packet Cable access | PktCbl | Rel-8 |
| Work task: CT4 aspects of PktCbl-Sec | PktCbl-Sec | Rel-8 |
| Building Block: Single Radio Voice Call Continuity for 3GPP (SRVCC) | SAES-SRVCC | Rel-8 |
| Building Block: Stage 3 for PNM | PNM | Rel-8 |
| Work task: SAES-SA-FP_LTE with GTP variant | SAES-SA-FP_LTE-GTP | Rel-8 |
| Work task: SAES-SA-FP_LTE with PMIP variant | SAES-SA-FP_LTE-IETF | Rel-8 |
| Work task: Stage 3 for EPC - HSS interface | SAES-LTE | Rel-8 |
| Work task: Deleted - User and Control plane protocols | SAES-St3-prot | Rel-8 |
| Work task: Stage 3 for SAE / LTE identities | SAES | Rel-8 |
| Feature or Study Item: Customized Alerting Tone (CAT) service | CAT | Rel-8 |
| Building Block: CT4 aspects of EVA | EVA | Rel-8 |
| Feature or Study Item: Enhancements for Voice Group Call Service (VGCS) Applications (EVA) | EVA | Rel-8 |
| Feature or Study Item: Voice Call Continuity between CS and IMS (incl. I-WLAN) | VCC | Rel-7 |
| Feature or Study Item: Enhancements to support QoS provisioning over 3GPP/WLAN Interworking | WLANQOS | Rel-7 |
| Feature or Study Item: WLAN Interworking – Private Network access from WLAN 3GPP IP Access | WLANPNA | Rel-7 |
| Feature or Study Item: System enhancements for Fixed Broadband access to IMS | FBI | Rel-7 |
| Feature or Study Item: Location Services enhancements | LCS3 | Rel-7 |
| Feature or Study Item: Support of SMS over generic 3GPP IP access | SMSIP | Rel-7 |
| Building Block: Stage 3 for SMSIP | SMSIP-St3 | Rel-7 |
| Work task: CT4 aspects for SMSIP | SMSIP-St3-c4 | Rel-7 |
| Work task: TCAPsec Gateway | SEC7-TCAP | Rel-7 |
| Feature or Study Item: CAMEL Trunk Triggers | TTCAMEL | Rel-7 |
| Feature or Study Item: Value-Added Services for Short Message Service | VAS4SMS | Rel-9 |
| Feature or Study Item: CS-IBCF and CS-TrGW definition in 3GPP specifications | CS-IBCF | Rel-9 |
| Building Block: CT4 aspects of CS-IBCF and CS-TrGW definition in 3GPP specifications | CS-IBCF | Rel-9 |
| Building Block: LCS Control Plane Solution for EPS | LCS_EPS-CPS | Rel-9 |
| Feature or Study Item: MBMS support in EPS | MBMS_EPS | Rel-9 |
| Feature or Study Item: Study on Support of (G)MSC-S - (G)MSC-S Nc Interface based on the SIP-I protocol | NcSIP | Rel-7 |
| Feature or Study Item: Routeing of MT-SMS via the HPLMN | SMSviaH | Rel-7 |
| Feature or Study Item: Mobile Termination whilst the MS is moving to another MSC | MTmovMS | Rel-7 |
| Building Block: Maintenance of TISPAN R1 | MAINT_R1 | Rel-7 |
| Feature or Study Item: Rel-10 Operations, Administration, Maintenance and Provisioning (OAM&P) | OAM10 | Rel-10 |
| Building Block: CT4 aspects of ETWS | ETWS | Rel-8 |
| Work task: CT4 part of CAT Service in 3GPP CS domain | CAT-3G_CS | Rel-8 |
| Building Block: Stage 3 Overlap (CT4) | Overlap | Rel-8 |
| Building Block: Deleted - Issues for CT4 TR 29.803 | SAES | Rel-8 |
| Building Block: CT4 aspects of IMS_Corp | IMS_Corp | Rel-8 |
| Work task: Stage 3 CIMS_3GPP2 (CT4) | REDOC_3GPP2 | Rel-8 |
| Feature or Study Item: 3GPP2 Input to Common IMS | CIMS_3GPP2 | Rel-8 |
| Building Block: CS Fallback in EPS | SAES-CSFB | Rel-8 |
| Feature or Study Item: Maintenance of TISPAN documentation | MAINTISP | Rel-8 |
| Work task: Documentation of TISPAN R1 and R2 in CT4 | REDOC_TIS-C4 | Rel-8 |
| Feature or Study Item: Support for IMS Emergency Calls over GPRS and EPS | IMS_EMER_GPRS_EPS | Rel-9 |
| Work task: CT aspects of SRVCC support for IMS Emergency Calls | IMS_EMER_GPRS_EPS-SRVCC | Rel-9 |
| Building Block: CN aspects of IMS Media Plane Security | MEDIASEC_CORE | Rel-9 |
| Work task: User Data Convergence (UDC) Protocol Description | UDC-CN | Rel-9 |
| Building Block: CT4 part of IMS Signalling Activated Trace | ISAT | Rel-14 |
| Work task: CT4 aspects of 5G Trace management | NETSLICE-5GTRACE-CT | Rel-15 |
| Work task: CT4 aspects of EvoLP | eVoLP-CT | Rel-15 |
| Work task: CT4 aspects of INOBEAR | INOBEAR-CT | Rel-15 |
| Work task: CT4 aspects of IMSo5G | 5GS_Ph1-IMSo5G | Rel-15 |
| Work task: CT4 aspects of EDCE5 | EDCE5-CT | Rel-15 |
| Building Block: Stage 3 of USOS | USOS-CT | Rel-15 |
| Work task: CT4 aspects of NAPS | NAPS-CT | Rel-15 |
| Work task: Stopped - CT4 aspects of LTE_LIGHT_CON | LTE_LIGHT_CON-CT | Rel-15 |
| Work task: CT4 aspects of 5G System - Phase 1 | 5GS_Ph1-CT | Rel-15 |
| Work task: CT4 aspects of VoWLAN | VoWLAN-CT | Rel-15 |
| Work task: CT4 aspects of ProSe_WLAN_DD | ProSe_WLAN_DD_Stage3 | Rel-15 |
| Work task: CT4 aspects of PS Data Off Phase 2 | PS_DATA_OFF2-CT | Rel-15 |
| Feature or Study Item: Study on User Plane Protocol in 5GC | FS_UPPS | Rel-16 |
| Feature or Study Item: 5GS Enhanced support of Over the air (OTA) mechanism for UICC configuration parameter update | 5GS_OTAF | Rel-16 |
| Feature or Study Item: Shared Data Handling on Nudm and Nudr | Shared_Data | Rel-16 |
| Work task: deleted- CT4 aspects of ePWS (Possible impacts) | ePWS | Rel-16 |
| Building Block: Study on Load and Overload Control of 5GC Service Based Interfaces | FS_LOLC | Rel-16 |
| Work task: CT4 aspects of 5WWC | 5WWC | Rel-16 |
| Building Block: CT aspects of UDICOM | UDICOM | Rel-16 |
| Work task: CT4 aspects of Vertical_LAN | Vertical_LAN | Rel-16 |
| Work task: CT4 aspects of 5G_CIoT | 5G_CIoT | Rel-16 |
| Work task: CT4 aspects of 5G_eLCS | 5G_eLCS | Rel-16 |
| Work task: CT4 aspects of eNA | eNA | Rel-16 |
| Work task: CT4 aspects of eNS | eNS | Rel-16 |
| Work task: CT4 aspects of ETSUN | ETSUN | Rel-16 |
| Work task: CT4 aspects of ATSSS | ATSSS | Rel-16 |
| Work task: CT4 aspects of 5G_eSBA | 5G_eSBA | Rel-16 |
| Work task: CT4 aspects of PARLOS | PARLOS | Rel-16 |
| Work task: CT4 Aspects of E2E_DELAY | E2E_DELAY | Rel-16 |
| Feature or Study Item: Nudsf Service Based Interface | NUDSF | Rel-16 |
| Feature or Study Item: Nsoraf Service Based Interface | NSORAF | Rel-16 |
| Work task: CT4 aspects of IABARC | IABARC | Rel-16 |
| Building Block: CT4 aspects of SBIProtoc16 | SBIProtoc16 | Rel-16 |
| Work task: CT4 aspects of RACS | RACS | Rel-16 |
| Work task: CT4 aspect of 5G_SRVCC | 5G_SRVCC | Rel-16 |
| Work task: CT4 Aspects of 5G_URLLC | 5G_URLLC | Rel-16 |
| Work task: CT4 aspects of eIMS5G_SBA | eIMS5G_SBA | Rel-16 |
| Work task: CT4 aspects of V2XAPP | V2XAPP | Rel-16 |
| Work task: CT4 aspects of eV2XARC | eV2XARC | Rel-16 |
| Feature or Study Item: Study on Nudsf Service Based Interface | FS_NUDSF | Rel-16 |
| Building Block: C4 aspects of 5GS_OTAF | 5GS_OTAF | Rel-16 |
| Building Block: C4 aspects of LOLC | LOLC | Rel-16 |
| Work task: CT4 aspects of xBDT | xBDT | Rel-16 |
| Building Block: CT4 aspects of eNAPIs | eNAPIs | Rel-16 |
| Building Block: CT4 aspects of ReP_UDR | ReP_UDR | Rel-17 |
| Work task: CT4 aspects for EDGEAPP | EDGEAPP | Rel-17 |
| Building Block: CT4 aspects on enhancement of RAN slicing for NR | NRslice | Rel-17 |
| Building Block: CT4 aspects of BEPoP | BEPoP | Rel-17 |
| Building Block: CT4 aspects of NB-IoT/eMTC Non-Terrestrial Networks in EPS | IoT_SAT_ARCH_EPS | Rel-17 |
| Building Block: CT4 aspects of NR_redcap | ARCH_NR_REDCAP | Rel-17 |
| Feature or Study Item: Repository for the 3GPP Allocated Port Numbers for New 3GPP Interfaces | PortAl | Rel-17 |
| Building Block: CT4 aspects of NSWO | NSWO_5G | Rel-17 |
| Building Block: Stage 3 CT4 for eCryptPr | eCryptPr | Rel-17 |
| Work task: CT4 aspects of N7 Interfaces Enhancements to Support GERAN and UTRAN | TEI17_NIESGU | Rel-17 |
| Building Block: CT4 aspects of NBI17 | NBI17 | Rel-17 |
| Work task: CT4 aspects of TEI17_SE_RPS | TEI17_SE_RPS | Rel-17 |
| Work task: CT4 aspects of MINT | MINT | Rel-17 |
| Feature or Study Item: Restoration of Profiles related to UDR | ReP_UDR | Rel-17 |
| Feature or Study Item: Enhancement on the GTP-U entity restart | EGTPUR | Rel-17 |
| Building Block: Stage 3 (CT4) of eCPSOR_CON | eCPSOR_CON | Rel-17 |
| Feature or Study Item: Enhancement of Inter-PLMN Roaming | EoIPR | Rel-17 |
| Work task: CT4 aspects of 5GC architecture for satellite networks | 5GSAT_ARCH-CT | Rel-17 |
| Building Block: CT4 aspects of FS_eIMS5G2 | FS_eIMS5G2 | Rel-17 |
| Work task: CT4 aspects of TEI17_N3SLICE | TEI17_N3SLICE | Rel-17 |
| Building Block: CT4 aspect of 5MBS | 5MBS | Rel-17 |
| Building Block: CT aspects of Integration of GBA into SBA | GBA_5G | Rel-17 |
| Feature or Study Item: Start of Pause of Charging via User Plane | SPOCUP | Rel-17 |
| Building Block: CT4 aspects of SMS_SBI | SMS_SBI | Rel-17 |
| Work task: CT4 aspects of AKMA | AKMA-CT | Rel-17 |
| Work task: CT4 aspects of eNS_Ph2 | eNS_Ph2 | Rel-17 |
| Work task: CT4 aspects on TEI17_SPSFAS | TEI17_SPSFAS | Rel-17 |
| Work task: CT4 aspects of 5G eEDGE | eEDGE_5GC | Rel-17 |
| Work task: CT4 aspects of 5G_eLCS_ph2 | 5G_eLCS_ph2 | Rel-17 |
| Work task: CT4 aspects of ATSSS_Ph2 | ATSSS_Ph2 | Rel-17 |
| Work task: CT4 aspects of support of enhanced Industrial IoT | IIoT | Rel-17 |
| Work task: CT4 aspects of Enabling Multi-USIM Devices | MUSIM | Rel-17 |
| Work task: CT4 aspects of eNPN | eNPN | Rel-17 |
| Work task: CT4 aspects for ID_UAS | ID_UAS | Rel-17 |
| Work task: CT4 aspects of 5G_ProSe | 5G_ProSe | Rel-17 |
| Work task: CT4 aspects on TEI17_DCAMP | TEI17_DCAMP | Rel-17 |
| Work task: CT4 aspects on TEI17_GEM | TEI17_GEM | Rel-17 |
| Work task: CT4 aspects of eNA_Ph2 | eNA_Ph2 | Rel-17 |
| Feature or Study Item: Study on Port Number Allocation Alternatives for New 3GPP Interfaces | FS_PortAl | Rel-17 |
| Work task: CT4 aspects of MPS2 | MPS2 | Rel-17 |
| Building Block: CT4 aspects of SBIProtoc17 | SBIProtoc17 | Rel-17 |
| Feature or Study Item: Study on restoration of profiles related to UDR | FS_ReP_UDR | Rel-17 |
| Feature or Study Item: Restoration of PDN Connections in PGW-C/SMF Set | RPCPSET | Rel-17 |
| Building Block: CT4 aspects of SBIProtoc18 | SBIProtoc18 | Rel-18 |
| Feature or Study Item: Study on NRF API enhancements to avoid signalling and storing of redundant data | FS_NRFe | Rel-18 |
| Feature or Study Item: Study on IETF QUIC Transport for Service Based Interfaces | FS_QUIC | Rel-18 |
| Feature or Study Item: NRF API enhancements to avoid signalling and storing of redundant data | NRFe | Rel-18 |
| Building Block: CT4 aspects of NSCALE | NSCALE | Rel-18 |
| Building Block: CT4 aspects on Dynamically Changing AM Policies in the 5GC Phase 2 | TEI18_DCAMP_Ph2 | Rel-18 |
| Building Block: CT4 aspects on TEI18_SLAMUP | TEI18_SLAMUP | Rel-18 |
| Building Block: CT4 aspects of IVAS_Codec | IVAS_Codec | Rel-18 |
| Building Block: CT aspects of home network triggered primary authentication | HN_Auth | Rel-18 |
| Building Block: Stopped – CT4 aspects of Slice-based PLMN Selection | PLMNsel_NS | Rel-18 |
| Building Block: CT4 aspects of MPS_WLAN | MPS_WLAN | Rel-18 |
| Building Block: CT4 aspects of PIN | PIN | Rel-18 |
| Building Block: CT4 aspects of UAS Ph2 | UAS_Ph2 | Rel-18 |
| Building Block: CT4 aspects of Ranging_SL | Ranging_SL | Rel-18 |
| Building Block: CT4 aspects of GMEC | GMEC | Rel-18 |
| Building Block: CT4 aspects of AIML | AIMLsys | Rel-18 |
| Building Block: CT4 aspects for 5MBS_Ph2 | 5MBS_Ph2 | Rel-18 |
| Building Block: CT4 aspects of Network Slicing Phase 3 | eNS_Ph3 | Rel-18 |
| Building Block: CT4 aspects of XRM | XRM | Rel-18 |
| Building Block: CT4 aspects of NG_RTC | NG_RTC | Rel-18 |
| Building Block: CT4 aspects of ATSSS_Ph3 | ATSSS_Ph3 | Rel-18 |
| Building Block: CT4 aspects of eUEPO | eUEPO | Rel-18 |
| Building Block: CT4 aspects of 5G AM Policy | AMP | Rel-18 |
| Building Block: CT4 aspects of VMR | VMR | Rel-18 |
| Building Block: CT4 aspects of eNA_Ph3 | eNA_Ph3 | Rel-18 |
| Building Block: CT4 aspects of UEP18 | UEP18 | Rel-18 |
| Building Block: 5GS support of NR RedCap UE with long eDRX for RRC_INACTIVE State | NR_REDCAP_Ph2 | Rel-18 |
| Building Block: CT4 aspects on TEI18_MLR | TEI18_MLR | Rel-18 |
| Building Block: CT aspects of 5G_eLCS_Ph3 | 5G_eLCS_Ph3 | Rel-18 |
| Feature or Study Item: Enhancement of Shared Data ID and Handling | ShDatID_H | Rel-18 |
| Building Block: CT aspects of eNSAC | eNSAC | Rel-18 |
| Building Block: CT4 aspects of UPF enhancement for exposure and SBA | UPEAS | Rel-18 |
| Feature or Study Item: Enhancements on Service-based support for SMS in 5GC | eSMS_SBI | Rel-18 |
| Building Block: CT4 aspects of 5GSATB | 5GSATB | Rel-18 |
| Building Block: CT4 aspects of 5G_eLCS_Ph3 | 5G_eLCS_Ph3 | Rel-18 |
| Building Block: CT4 aspects of 5G_ProSe_Ph2 | 5G_ProSe_Ph2 | Rel-18 |
| Building Block: CT4 aspects of NR_REDCAP_Ph2 | NR_REDCAP_Ph2 | Rel-18 |
| Building Block: deleted - CT4 aspects of eMCSMI_IRail | eMCSMI_IRail | Rel-18 |
| Building Block: CT4 aspects of EDGE_Ph2 | EDGE_Ph2 | Rel-18 |
| Building Block: CT4 aspects of eNPN_Ph2 | eNPN_Ph2 | Rel-18 |
| Building Block: CT4 aspects of 5WWC_Ph2 | 5WWC_Ph2 | Rel-18 |
| Building Block: CT4 aspects of eNSAC | eNSAC | Rel-18 |
| Building Block: CT4 aspects of Seamless UE context recovery | SUECR | Rel-18 |
| Building Block: CT4 aspects of SFC | SFC | Rel-18 |
| Building Block: CT4 aspects of Detnet | DetNet | Rel-18 |
| Building Block: CT4 aspects of TEI18_IPv6PD | TEI18_IPv6PD | Rel-18 |
| Building Block: CT4 aspects of TEI18_SDNAEPC | TEI18_SDNAEPC | Rel-18 |
| Building Block: CT4 aspects of TRS_URLLC | TRS_URLLC | Rel-18 |
| Building Block: CT4 aspects of MCProtoc18 | MCProtoc18 | Rel-18 |
| Feature or Study Item: Study on Reducing Information Exposure over SBI | FS_RedInfExp_SBI | Rel-19 |
| Feature or Study Item: Study on IMS Disaster Prevention and Restoration Enhancement | FS_IMS_RES | Rel-19 |
| Building Block: CT aspects of UPF enhancement for Exposure And SBA Phase 2 | UPEAS_Ph2 | Rel-19 |
| Building Block: CT aspects of Architecture support of roaming value-added services | TEI19_RVAS | Rel-19 |
| Building Block: CT aspects of On-demand broadcast of GNSS assistance data | TEI19_OBGAD | Rel-19 |
| Building Block: CT aspects of indirect network sharing | TEI19_NetShare | Rel-19 |
| Building Block: CT aspects of NF discovery and selection by target PLMN | TEI19_NFsel_by_tPLMN | Rel-19 |
| Building Block: CT aspects of Enhancement of support for Edge Computing in 5G Core network - Phase 3 | eEDGE_5GC_Ph3 | Rel-19 |
| Building Block: CT aspects of MPS for IMS Messaging and SMS services | MPS4msg | Rel-19 |
| Building Block: CT4 aspects of Service Based Interface Protocol Improvements Release 19 | SBIProtoc19 | Rel-19 |
| Work task: CT4 Aspects on Minimize the Number of Policy Associations | TEI19_MINPA | Rel-19 |
| Work task: CT4 aspects of Providing per-subscriber VLAN instructions from UDM and DN-AAA | TEI19_VLANSUB | Rel-19 |
| Work task: CT4 aspects of Enhancing Parameter Provisioning with static UE IP address and UP security policy | TEI19_IP_SP_EXP | Rel-19 |
| Building Block: CT4 aspects of Protocol enhancements for Mission Critical Services | MCProtoc19 | Rel-19 |
| Building Block: CT4 aspects of Enhancement of controlling RAT utilization | ECRATU | Rel-19 |
| Feature or Study Item: Subscriber Data Migration | SUBDMIG | Rel-19 |
| Building Block: CT Aspects on Minimize the Number of Policy Associations | TEI19_MINPA | Rel-19 |
| Feature or Study Item: Study on Protocol for AI Data Collection from UPF | FS_PAIDC_UPF | Rel-19 |
| Work task: CT4 aspects of Proximity-based Services in 5GS Phase 3 | 5G_ProSe_Ph3 | Rel-19 |
| Work task: CT4 aspects of integration of satellite components in the 5G architecture Phase 3 | 5GSAT_Ph3_ARCH | Rel-19 |
| Work task: CT4 aspects of Core Network Enhanced Support for Artificial Intelligence (AI)/Machine Learning (ML) | AIML_CN | Rel-19 |
| Work task: CT4 aspects of Enhancement of support for Edge Computing in 5G Core network - Phase 3 | eEDGE_5GC_Ph3 | Rel-19 |
| Work task: CT4 aspects of Multi-Access (ATSSS_Ph4) | MASSS | Rel-19 |
| Work task: CT4 aspects of Application enablement for mobile metaverse services | Metaverse_App | Rel-19 |
| Work task: CT4 aspects of MPS for IMS Messaging and SMS services | MPS4msg | Rel-19 |
| Work task: CT4 aspects of System architecture for Next Generation Real time Communication services Phase 2 | NG_RTC_Ph2 | Rel-19 |
| Work task: CT4 aspects of indirect network sharing | TEI19_NetShare | Rel-19 |
| Work task: CT4 aspects of NF discovery and selection by target PLMN | TEI19_NFsel_by_tPLMN | Rel-19 |
| Work task: CT4 aspects of On-demand broadcast of GNSS assistance data | TEI19_OBGAD | Rel-19 |
| Work task: CT4 aspects of ProSe support in NPN | TEI19_ProSe_NPN | Rel-19 |
| Work task: CT4 aspects of QoS monitoring enhancement | TEI19_QME | Rel-19 |
| Work task: CT4 aspects of Architecture support of roaming value-added services | TEI19_RVAS | Rel-19 |
| Work task: CT4 aspects of Identifying non-3GPP Devices Connecting behind a UE or 5G-RG | UIA_ARC | Rel-19 |
| Work task: CT4 aspects of UPF enhancement for Exposure And SBA Phase 2 | UPEAS_Ph2 | Rel-19 |
| Work task: CT4 aspects of Vehicle Mounted Relays Phase 2 | VMR_Ph2 | Rel-19 |
| Building Block: CT aspects of Identifying non-3GPP Devices Connecting behind a UE or 5G-RG | UIA_ARC | Rel-19 |
