Proper noun
AAL2
(electronics) Asynchronous Transfer Mode Adaption Layer Type 2, ATM Adaption Layer Type 2.
AAL2 through AAL4 are used for variable bitrate (VBR) services, and AAL5 for data. Source: Internet
Standardized AALs include AAL1, AAL2, and AAL5, and the rarely used AAL3 and AAL4. Source: Internet