{"topic":{"id":"ng-ran-split","name":"NG-RAN Functional Split","summary":"gNB-CU-CP, gNB-CU-UP and gNB-DU architecture with F1 and E1 control relationships.","facets":["CU-CP","CU-UP","DU","F1","E1","User plane"],"provenance_type":"curated","review_state":"reviewed","source_url":"https://www.3gpp.org/dynareport/38401.htm","valid_from_release":"Rel-15","valid_to_release":null},"release":"Rel-7","release_state":{"applicable":false,"note":"reviewed mapping begins in Rel-15"},"specifications":[{"number":"38.401","type":"TS","title":"NG-RAN; Architecture description","status":"Under change control","initial_release":"Rel-15","primary_group":"R3","portal_url":"https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3219","dynareport_url":"https://www.3gpp.org/dynareport/38401.htm","classifications":[],"lineage_layer":{"id":"ran_realization","label":"RAN / radio realization","provenance_type":"inferred","review_state":"candidate","source_url":null,"note":"Orientation inferred from the 38-series; this is not an official 3GPP stage assignment."}},{"number":"38.473","type":"TS","title":"NG-RAN; F1 Application Protocol (F1AP)","status":"Under change control","initial_release":"Rel-15","primary_group":"R3","portal_url":"https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3260","dynareport_url":"https://www.3gpp.org/dynareport/38473.htm","classifications":[],"lineage_layer":{"id":"ran_realization","label":"RAN / radio realization","provenance_type":"inferred","review_state":"candidate","source_url":null,"note":"Orientation inferred from the 38-series; this is not an official 3GPP stage assignment."}},{"number":"38.463","type":"TS","title":"NG-RAN; E1 Application Protocol (E1AP)","status":"Under change control","initial_release":"Rel-15","primary_group":"R3","portal_url":"https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3431","dynareport_url":"https://www.3gpp.org/dynareport/38463.htm","classifications":[],"lineage_layer":{"id":"ran_realization","label":"RAN / radio realization","provenance_type":"inferred","review_state":"candidate","source_url":null,"note":"Orientation inferred from the 38-series; this is not an official 3GPP stage assignment."}},{"number":"29.281","type":"TS","title":"General Packet Radio System (GPRS) Tunnelling Protocol User Plane (GTPv1-U)","status":"Under change control","initial_release":"Rel-8","primary_group":"C4","portal_url":"https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1699","dynareport_url":"https://www.3gpp.org/dynareport/29281.htm","classifications":[],"lineage_layer":{"id":"core_protocol","label":"Core-network protocol & service realization","provenance_type":"inferred","review_state":"candidate","source_url":null,"note":"Orientation inferred from the 29-series; this is not an official 3GPP stage assignment."}}],"layers":[{"id":"core_protocol","label":"Core-network protocol & service realization","specifications":[{"number":"29.281","type":"TS","title":"General Packet Radio System (GPRS) Tunnelling Protocol User Plane (GTPv1-U)","status":"Under change control","initial_release":"Rel-8","primary_group":"C4","portal_url":"https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1699","dynareport_url":"https://www.3gpp.org/dynareport/29281.htm","classifications":[],"lineage_layer":{"id":"core_protocol","label":"Core-network protocol & service realization","provenance_type":"inferred","review_state":"candidate","source_url":null,"note":"Orientation inferred from the 29-series; this is not an official 3GPP stage assignment."}}]},{"id":"ran_realization","label":"RAN / radio realization","specifications":[{"number":"38.401","type":"TS","title":"NG-RAN; Architecture description","status":"Under change control","initial_release":"Rel-15","primary_group":"R3","portal_url":"https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3219","dynareport_url":"https://www.3gpp.org/dynareport/38401.htm","classifications":[],"lineage_layer":{"id":"ran_realization","label":"RAN / radio realization","provenance_type":"inferred","review_state":"candidate","source_url":null,"note":"Orientation inferred from the 38-series; this is not an official 3GPP stage assignment."}},{"number":"38.473","type":"TS","title":"NG-RAN; F1 Application Protocol (F1AP)","status":"Under change control","initial_release":"Rel-15","primary_group":"R3","portal_url":"https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3260","dynareport_url":"https://www.3gpp.org/dynareport/38473.htm","classifications":[],"lineage_layer":{"id":"ran_realization","label":"RAN / radio realization","provenance_type":"inferred","review_state":"candidate","source_url":null,"note":"Orientation inferred from the 38-series; this is not an official 3GPP stage assignment."}},{"number":"38.463","type":"TS","title":"NG-RAN; E1 Application Protocol (E1AP)","status":"Under change control","initial_release":"Rel-15","primary_group":"R3","portal_url":"https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3431","dynareport_url":"https://www.3gpp.org/dynareport/38463.htm","classifications":[],"lineage_layer":{"id":"ran_realization","label":"RAN / radio realization","provenance_type":"inferred","review_state":"candidate","source_url":null,"note":"Orientation inferred from the 38-series; this is not an official 3GPP stage assignment."}}]}],"primary_work_item":null,"connected_work_items":[{"database_id":250471,"uid":2544,"acronym":"MBMS","effective_acronym":"MBMS","title":"Multimedia Broadcast and Multicast Service","release":"Rel-6","status":"Awaiting approval","responsible_groups":["R2","R4","S1","S2","S3","S4","S5","R5"],"completion_rate":100.0,"latest_remark":"-","work_plan_synced_at":"2026-10-07T21:46:47.945228+00:00","source_url":"https://portal.3gpp.org/desktopmodules/WorkItem/WorkItemDetails.aspx?workitemId=2544","work_plan_source_url":"https://www.3gpp.org/ftp/Information/WORK_PLAN/Work_plan_3gpp_2026_09_28.xlsx","specifications":["29.281"],"specification_associations":[{"number":"29.281","association_sources":["portal-spec"],"association_status":"source_tracked"}],"lineage_scope":"connected_to_mapped_specification"}],"relationships":[{"id":7,"source_spec":"38.473","target_spec":"38.401","edge_type":"interface_specification","provenance_type":"curated","confidence":1.0,"review_state":"reviewed","source_url":"atlas://curated/dependency-edges","valid_from_release":null,"valid_to_release":null}],"change_requests":{"primary_work_item":[],"release_context":[]},"traceability_summary":{"mapped_specifications":4,"explicit_stage_classifications":0,"inferred_layer_orientations":4,"release_valid_relationships":1,"connected_work_items":1,"primary_work_item_crs":0,"release_context_crs":0},"limitations":["The reviewed topic-to-specification mapping is Atlas-curated and non-normative even when its source is an official 3GPP record.","When an explicit stage classification is unavailable, specification layers are inferred from the TS/TR series and are labelled inferred rather than presented as official 3GPP stage assignments.","Connected Work Items and release-context Change Requests share mapped specifications; only the topic source Work Item is treated as primary evidence for the reviewed topic mapping.","This is traceability evidence and navigation, not a clause-by-clause normative feature definition."]}