I read some portion of imc_isc_mod.c, specially isc_from_as function. In that function there is some function call that searching for some marks in the SIP message. Also I read section 5.7.3 from TS 24.229 but I didn't find the marking mechanism that used in isc_from_as function.

Would you please point me to the technical specification that implemented in IMS_ISC module?

Regards,

Ali