Session establishment with a local serving network

A policy control function (PCF) configured to enable a terminal device to establish a communication session with a local serving network, the PCF comprising processing circuitry configured to cause the PCF to:

• select a first User Equipment Route Selection Policy (URSP) rule if the local serving network is a home network, or select a second URSP rule if the local serving network is a roaming network;
• obtain a modification to the selected URSP rule used by the terminal device for establishing a communication session with the local serving network for communicating traffic, the selected URSP rule being associated with a validity condition for the communication session, the validity condition pertaining to support for IP Multimedia Subsystem (IMS) in the local serving network, the validity condition requiring that IMS voice over PS is supported in the local serving network;
• and
• provide the modification of the selected URSP rule towards the terminal device.

A method performed by a terminal device for establishing a communication session with a local serving network, the method comprising:

• obtaining a modification of a User Equipment Route Selection Policy, USRP, rule and a validity condition, the validity condition requiring that IP Multimedia Subsystem (IMS) voice over PS is supported in the local serving network;
• obtaining an indication of traffic to be communicated, the traffic being associated with a traffic descriptor;
• select the first User Equipment Route Selection Policy (URSP) rule if the local serving network is a home network, or select a second URSP rule if the local serving network is a roaming network;
• the selected URSP rule for the traffic to be communicated in a communication session with the local serving network, the selected URSP rule being selected in accordance with the traffic descriptor and in accordance with the validity condition, the validity condition pertaining to support for IP IMS in the local serving network;
• and
• establishing a communication session with the local serving network for communicating the traffic according to the selected URSP rule.

A method performed by a policy control function (PCF) of a local serving network for enabling a terminal device to establish a communication session with the local serving network, the method comprising:

• selecting a first User Equipment Route Selection Policy (URSP) rule if the local serving network is a home network, or select a second URSP rule if the local serving network is a roaming network;
• obtaining a modification to the selected URSP rule used by the terminal device for establishing a communication session with the local serving network for communicating traffic, the selected URSP rule being associated with a validity condition for the communication session, the validity condition pertaining to support for IP Multimedia Subsystem (IMS) in the local serving network, the validity condition requiring that IMS voice over PS is supported in the local serving network;
• and
• providing the modification of the selected URSP rule towards the terminal device.