Hi Ashish,
Better read on MTP Layers and C7 Network Management by MTP3.
Th links are managed by MTP Layers.While CIC Informations goes through USER PART Layer-Upper Layer.
So ISUP Layer wont care about how MTP Transports the Message it gives the SIF to MTP which can send the message in a available SL or If you Have ATM/IP(New Trends ) as Physical Links MTP sends through them.
Rgds