ciscoAtmVplCrossVpi 1.3.6.1.4.1.9.10.13.1.1.1.1.15

This specifies the VPI value of the VPL to which this VPL is cross-connected. For point to multi-point connection, this is the root VPL's VPI for the leaf entry. Similarly it is the 1st leaf's VPI value for the root entry.