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Glossary

CSCF (Call Session Control Function) in 3GPP: meaning and where it is specified

Published 2026-10-16Updated 2026-10-16

At a glance

Term
CSCF
Stands for
Call Session Control Function
Defined in
3GPP TS 23.002 V19.0.0, clause 4a.7.1
TR 21.905 also lists
Call Server Control Function
Used in
TS 23.228, TS 24.229, TS 26.114

In plain words

For an IMS multimedia telephony call, CSCF mechanisms are used "to route control-plane signalling between the UEs involved in the call". TS 23.002 says CSCF can act as proxy, serving, emergency, or interrogating CSCF. 3GPP uses CSCF in TS 23.228 for S-CSCF session control, TS 24.229 for the UE interface, and TS 26.114 for IMS telephony signalling.

Source: 3GPP TS 26.114 V19.3.0, clause 4.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/26_series/26.114/26114-j30.zip

Sources

  1. 3GPP TS 26.114 V19.3.0, clause 4.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/26_series/26.114/26114-j30.zip
  2. 3GPP TS 23.002 V19.0.0, clause 4a.7.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/23_series/23.002/23002-j00.zip
  3. 3GPP TS 24.229 V20.1.0, clause 1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/24_series/24.229/24229-k10.zip
  4. 3GPP TS 23.228 V20.1.0, clause 4.6.3. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/23_series/23.228/23228-k10.zip

How this page was made

The facts box comes straight from the 3GPP TDoc list and specification archive as indexed by 3GPP Scout. An AI model (GPT-6 Luna) wrote the paragraph and named the source of each sentence. Code checked every quote word for word against the stored source text and every number against the cited source. A second AI model from another company (Claude Opus 5.5) reviewed the paragraph against the same sources. The 3GPP documents themselves govern.