A method of operation of a network node (14, 24) in a cellular communications network that comprises a radio access network and a core network, the method comprising: selecting a user plane function (16, 20) for a protocol data unit session for a wireless device based on information related to application server selection such that the protocol data unit session for the wireless device utilizes the selected user plane function (16, 20), receiving, from another network node, a message comprising a list of candidate Packet Processing Function, PPF, pools for the protocol data unit session for the wireless device, each candidate PPF pool in the list of candidate PPF pools comprising one or more PPFs wherein a PPF is a user plane function in the radio access network; selecting a list of candidate User Plane Function, UPF, pools for the protocol data unit session for the wireless device, each candidate UPF pool in the list of candidate UPF pools comprising one or more UPFs wherein a UPF is a user plane function in the core network; providing, to an Application Function, AF,, information comprising: (a) the list of candidate PPF pools and the list of candidate UPF pools or (b) combined information obtained by combining the list of candidate PPF pools and the list of candidate UPF pools; and receiving, from the AF, Application Server, AS, related information comprising: (a) information that indicates an AS selected for the wireless device and/or (b) information that indicates at least one UPF pool from the list of candidate UPF pools and/or (c) information that indicates at least one PPF pool from the list of candidate PPF pools; wherein: selecting the user plane function (16, 20) comprises selecting a UPF for the protocol data unit session for the wireless device based on the AS related information; and the method further comprises sending a message comprising an indication of the selected UPF to another network node, and wherein the network node (14, 24) is a Session Management Function, SMF,, the SMF being in the core network. selecting a user plane function (16, 20) for a protocol data unit session for a wireless device based on information related to application server selection such that the protocol data unit session for the wireless device utilizes the selected user plane function (16, 20), receiving, from another network node, a message comprising a list of candidate Packet Processing Function, PPF, pools for the protocol data unit session for the wireless device, each candidate PPF pool in the list of candidate PPF pools comprising one or more PPFs wherein a PPF is a user plane function in the radio access network; selecting a list of candidate User Plane Function, UPF, pools for the protocol data unit session for the wireless device, each candidate UPF pool in the list of candidate UPF pools comprising one or more UPFs wherein a UPF is a user plane function in the core network; providing, to an Application Function, AF,, information comprising: (a) the list of candidate PPF pools and the list of candidate UPF pools or (b) combined information obtained by combining the list of candidate PPF pools and the list of candidate UPF pools; and receiving, from the AF, Application Server, AS, related information comprising: (a) information that indicates an AS selected for the wireless device and/or (b) information that indicates at least one UPF pool from the list of candidate UPF pools and/or (c) information that indicates at least one PPF pool from the list of candidate PPF pools; selecting the user plane function (16, 20) comprises selecting a UPF for the protocol data unit session for the wireless device based on the AS related information; and the method further comprises sending a message comprising an indication of the selected UPF to another network node, and wherein the network node (14, 24) is a Session Management Function, SMF,, the SMF being in the core network.