Many users have in common the same filter criteria. In
this case it is more efficient to transmit this as just
an id in the SAA in order to save space in the XML with
the service profile and also possibly on the S-CSCF
storage. 3GPP Rel.6/7 specifies such an optional
mechanism - Shared IFC Sets. The task is to
design/implement a method of provisioning on the HSS
and distribution towards the S-CSCFs of these sets.