A method of determining whether access points of a non-cellular wireless communications network are capable of providing network mobility to data sessions of a wireless communication device, the wireless communication device having a cellular wireless network interface and a non-cellular wireless network interface, and being connected to a cellular wireless network, the method being performed by a system comprising a virtual bonding interface, and an Access Network Discovery and Selection Function,ANDSF, server, the virtual bonding interface forming part of the wireless communication device and being responsible for controlling the cellular wireless network interface and the non-cellular wireless network interface, the method comprising, at the virtual bonding interface, the steps of: determining whether Proxy Mobile IP, PMIP, is required for the data sessions, based on current requirements of existing data sessions; if PMIP is required, the method being characterised in that it further comprises the steps of: detecting, using the non-cellular wireless network interface, surrounding access points of the non-cellular wireless network; sending, via the cellular wireless network interface, a list of the detected surrounding access points to a Access Network Discovery and Selection Function (ANDSF)server; receiving a response from the ANDSF server, via the cellular wireless network interface, containing information relating to whether the wireless communication device is allowed to have PMIP access and whether the detected access points are PMIP enabled (s21, s23, s25); processing the received response to select one of the detected access points that are PMIP enabled, thereby to cause the wireless communication device to connect to the selected access point of the non-cellular wireless network. determining whether Proxy Mobile IP, PMIP, is required for the data sessions, based on current requirements of existing data sessions; if PMIP is required, the method being characterised in that it further comprises the steps of: detecting, using the non-cellular wireless network interface, surrounding access points of the non-cellular wireless network; sending, via the cellular wireless network interface, a list of the detected surrounding access points to a Access Network Discovery and Selection Function (ANDSF)server; receiving a response from the ANDSF server, via the cellular wireless network interface, containing information relating to whether the wireless communication device is allowed to have PMIP access and whether the detected access points are PMIP enabled (s21, s23, s25); processing the received response to select one of the detected access points that are PMIP enabled, thereby to cause the wireless communication device to connect to the selected access point of the non-cellular wireless network. detecting, using the non-cellular wireless network interface, surrounding access points of the non-cellular wireless network; sending, via the cellular wireless network interface, a list of the detected surrounding access points to a Access Network Discovery and Selection Function (ANDSF)server; receiving a response from the ANDSF server, via the cellular wireless network interface, containing information relating to whether the wireless communication device is allowed to have PMIP access and whether the detected access points are PMIP enabled (s21, s23, s25); processing the received response to select one of the detected access points that are PMIP enabled, thereby to cause the wireless communication device to connect to the selected access point of the non-cellular wireless network.