3GPP Scout / Glossary

Glossary

AAL2 (ATM Adaptation Layer type 2) in 3GPP: meaning and where it is specified

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

At a glance

Term
AAL2
Stands for
ATM Adaptation Layer type 2
Defined in
3GPP TR 21.905 V19.2.0, clause 4
Used in
TS 25.414, TS 25.426, TS 25.434

In plain words

AAL2 means ATM Adaptation Layer type 2, as defined in TR 21.905. TS 25.426 mentions "ATM Adaptation Layer type 2 (AAL2)" in its ATM Transport Option section, and TS 25.414 has a section on the AAL2 Signalling Protocol (Q.2630.2). For Iub, TS 25.434 says Q.2630.2 is selected as the standard AAL2 signalling protocol.

Source: 3GPP TS 25.426 V19.0.0, clause 5.2. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/25_series/25.426/25426-j00.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 25.426 V19.0.0, clause 5.2. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/25_series/25.426/25426-j00.zip
  3. 3GPP TS 25.414 V17.0.0, clause 5.2.2.1.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/25_series/25.414/25414-h00.zip
  4. 3GPP TS 25.434 V17.0.0, clause 6.2. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/25_series/25.434/25434-h00.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.