This Supplement to the Q series of ITU-T Recommendations specifies the general aspects of AAL type 2 signalling requirements for the development of AAL type 2 signalling Capability Set 2 . It should be read in conjunction with ITU-T Q-Series Supplement 8 realise the full set of requirements. This Supplement identifies what can be viewed as the capabilities for AAL type 2 Signalling. In addition, it describes the essential features and models useful for the development of functional entity actions in support of AAL type 2 Signalling.