An arbitrary index that uniquely identifies one or a group
of DS0s to be connected to an AAL1 trunking connection.
When catmtAal1Nx64Enable is set to 'false', the AAL1
trunking connection can only be a mapping of one single DS0
to one AAL1 ATM connection.
This object is mandatory when adding an AAL1 entry. Once
an AAL1 entry is added, this object can not be modified.