An apparatus for handling communications in a second network, comprising: means for receiving, as part of a call setup related signalling from a first network, an indication indicating a type of a network interface between the first network and the second network with respect to the call setup signalling, wherein the indication is received during set up of a communication session through the first network and the second network, wherein the indication of the type of network interface, indicates one of: a) call setup over interface from a visited network (V-PLMN A) of a calling user to a home network (H-PLMN A) of the calling user, b) call setup over interface from a home network (H-PLMN A) of a calling user to a visited network (V-PLMN A) of the calling user, with loopback, c) call setup over interface from a home network (H-PLMN A) of a calling user to a home network (H-PLMN B) of a called user, d) call setup over interface from a visited network (V-PLMN A) of a calling user to a home network (H-PLMN B) of a called user, e) call setup over interface from a home network (H-PLMN B) of a called user to a visited network (V-PLMN B) of the called user, f) call setup over interface from a session control node (S-CSCF A / AS A) controlling a calling user to a media resource function (MRF A), and, g) setup over interface from a media resource function (MRF A) to a session control node (S-CSCF A / AS A), and, means for processing the communication session based on the type of the network interface. means for receiving, as part of a call setup related signalling from a first network, an indication indicating a type of a network interface between the first network and the second network with respect to the call setup signalling, wherein the indication is received during set up of a communication session through the first network and the second network, wherein the indication of the type of network interface, indicates one of: a) call setup over interface from a visited network (V-PLMN A) of a calling user to a home network (H-PLMN A) of the calling user, b) call setup over interface from a home network (H-PLMN A) of a calling user to a visited network (V-PLMN A) of the calling user, with loopback, c) call setup over interface from a home network (H-PLMN A) of a calling user to a home network (H-PLMN B) of a called user, d) call setup over interface from a visited network (V-PLMN A) of a calling user to a home network (H-PLMN B) of a called user, e) call setup over interface from a home network (H-PLMN B) of a called user to a visited network (V-PLMN B) of the called user, f) call setup over interface from a session control node (S-CSCF A / AS A) controlling a calling user to a media resource function (MRF A), and, g) setup over interface from a media resource function (MRF A) to a session control node (S-CSCF A / AS A), and, means for processing the communication session based on the type of the network interface. a) call setup over interface from a visited network (V-PLMN A) of a calling user to a home network (H-PLMN A) of the calling user, b) call setup over interface from a home network (H-PLMN A) of a calling user to a visited network (V-PLMN A) of the calling user, with loopback, c) call setup over interface from a home network (H-PLMN A) of a calling user to a home network (H-PLMN B) of a called user, d) call setup over interface from a visited network (V-PLMN A) of a calling user to a home network (H-PLMN B) of a called user, e) call setup over interface from a home network (H-PLMN B) of a called user to a visited network (V-PLMN B) of the called user, f) call setup over interface from a session control node (S-CSCF A / AS A) controlling a calling user to a media resource function (MRF A), and, g) setup over interface from a media resource function (MRF A) to a session control node (S-CSCF A / AS A), and, means for processing the communication session based on the type of the network interface.