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Glossary

SAPI (Service Access Point Identifier) in 3GPP: meaning and where it is specified

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

At a glance

Term
SAPI
Stands for
Service Access Point Identifier
Defined in
3GPP TR 21.905 V19.2.0, clause 4
Used in
TS 23.110, TS 24.008, TS 48.056

In plain words

SAPI means Service Access Point Identifier, and TS 23.110 states "SAPs are identified by a SAPI at the AS boundary." TS 48.056 has a clause titled Service Access Point Identifier (SAPI), showing where the term appears in that specification. TS 24.008 uses the label LLC service access point identifier and includes the value LLC SAPI not assigned.

Source: 3GPP TS 23.110 V18.0.0, clause 6.1.3. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/23_series/23.110/23110-i00.zip

Sources

  1. 3GPP TR 21.905 V19.2.0, clause 4. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/21_series/21.905/21905-j20.zip
  2. 3GPP TS 23.110 V18.0.0, clause 6.1.3. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/23_series/23.110/23110-i00.zip
  3. 3GPP TS 48.056 V18.0.0, clause 6.1.3. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/48_series/48.056/48056-i00.zip
  4. 3GPP TS 24.008 V19.5.0, clause 10.5.6.9. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/24_series/24.008/24008-j50.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.