A Policy Control Function, PCF, apparatus comprising: a transceiver that is adapted to communicate with one or more functions in a mobile communication network; and a processor that is adapted to: receive, from a network Session Management Function, a policy request message in response to a remote unit requesting a multi-access data connection with the mobile communication network over a first access network (215, 120) and a second access network (220, 130), the policy request message indicating the remote unit supports access network performance measurements; derive at least one traffic steering rule that contains an access network performance "ANP" parameter, the traffic steering rule indicating to which of the first and second access networks data traffic of the multi-access data connection is to be routed according to a measured value of the ANP parameter; determine measurement assistance information for the remote unit in response to the at least one traffic steering rule that contains an ANP parameter; and return the at least one traffic steering rule that contains an ANP parameter and the measurement assistance information in response to the policy request message. a transceiver that is adapted to communicate with one or more functions in a mobile communication network; and a processor that is adapted to: receive, from a network Session Management Function, a policy request message in response to a remote unit requesting a multi-access data connection with the mobile communication network over a first access network (215, 120) and a second access network (220, 130), the policy request message indicating the remote unit supports access network performance measurements; derive at least one traffic steering rule that contains an access network performance "ANP" parameter, the traffic steering rule indicating to which of the first and second access networks data traffic of the multi-access data connection is to be routed according to a measured value of the ANP parameter; determine measurement assistance information for the remote unit in response to the at least one traffic steering rule that contains an ANP parameter; and return the at least one traffic steering rule that contains an ANP parameter and the measurement assistance information in response to the policy request message. receive, from a network Session Management Function, a policy request message in response to a remote unit requesting a multi-access data connection with the mobile communication network over a first access network (215, 120) and a second access network (220, 130), the policy request message indicating the remote unit supports access network performance measurements; derive at least one traffic steering rule that contains an access network performance "ANP" parameter, the traffic steering rule indicating to which of the first and second access networks data traffic of the multi-access data connection is to be routed according to a measured value of the ANP parameter; determine measurement assistance information for the remote unit in response to the at least one traffic steering rule that contains an ANP parameter; and return the at least one traffic steering rule that contains an ANP parameter and the measurement assistance information in response to the policy request message.