A method of establishing a Voice over Internet Protocol, VoIP, call between a calling User Equipment, UE, and a called UE, wherein said calling UE is served by a packet switched, PS, core network via a radio access network, RAN, and wherein a bearer is to be established between said calling UE and a gateway node in said PS core network, over said RAN, for obtaining access to an Internet Protocol, IP, multimedia subsystem, IMS, network, wherein said method is characterized by the steps of: - receiving, by an IMS Call Session Control Function, CSCF, node a notification message thereby notifying said IMS node that said VoIP call establishment is in progress; - enabling, by said IMS CSCF, retry of said establishment of said bearer between said calling UE and said gateway node, over said RAN, in case said establishment of said bearer has failed due to a temporary failure, wherein said step of enabling comprises any one of: i) providing, by said IMS CSCF, to said gateway node, a list of failure cause codes for which said gateway node is allowed to retry establishment of said bearer, and, when the gateway node determines that a detected cause for failure matches an entry said list of failure cause codes received from the IMS CSCF, the gateway node retries to establish that same bearer; or ii) receiving, by said IMS CSCF, a failure message thereby indicating that said bearer establishment between said calling UE and said gateway node has failed, determining, by said IMS CSCF, that said failure message comprises an indication that said failure is temporary based on a predetermined list of failure cause codes, and requesting, by said IMS CSCF, said gateway node, to retry to establish said bearer between said calling UE and said gateway node, or iii) receiving, by said IMS CSCF, a failure message thereby indicating that said bearer establishment between said calling UE and said gateway node has failed, determining, by said IMS CSCF, that said failure message comprises an indication that said failure is temporary based on a predetermined list of failure cause codes, and requesting, by said IMS CSCF, said calling UE to either retry to establish said Voice over Internet Protocol, VoIP, call between a calling User Equipment, UE, and said called UE via said radio access network, RAN, or to request said calling UE to re-register to said IMS network. - receiving, by an IMS Call Session Control Function, CSCF, node a notification message thereby notifying said IMS node that said VoIP call establishment is in progress; - enabling, by said IMS CSCF, retry of said establishment of said bearer between said calling UE and said gateway node, over said RAN, in case said establishment of said bearer has failed due to a temporary failure, wherein said step of enabling comprises any one of: i) providing, by said IMS CSCF, to said gateway node, a list of failure cause codes for which said gateway node is allowed to retry establishment of said bearer, and, when the gateway node determines that a detected cause for failure matches an entry said list of failure cause codes received from the IMS CSCF, the gateway node retries to establish that same bearer; or ii) receiving, by said IMS CSCF, a failure message thereby indicating that said bearer establishment between said calling UE and said gateway node has failed, determining, by said IMS CSCF, that said failure message comprises an indication that said failure is temporary based on a predetermined list of failure cause codes, and requesting, by said IMS CSCF, said gateway node, to retry to establish said bearer between said calling UE and said gateway node, or iii) receiving, by said IMS CSCF, a failure message thereby indicating that said bearer establishment between said calling UE and said gateway node has failed, determining, by said IMS CSCF, that said failure message comprises an indication that said failure is temporary based on a predetermined list of failure cause codes, and requesting, by said IMS CSCF, said calling UE to either retry to establish said Voice over Internet Protocol, VoIP, call between a calling User Equipment, UE, and said called UE via said radio access network, RAN, or to request said calling UE to re-register to said IMS network. i) providing, by said IMS CSCF, to said gateway node, a list of failure cause codes for which said gateway node is allowed to retry establishment of said bearer, and, when the gateway node determines that a detected cause for failure matches an entry said list of failure cause codes received from the IMS CSCF, the gateway node retries to establish that same bearer; or ii) receiving, by said IMS CSCF, a failure message thereby indicating that said bearer establishment between said calling UE and said gateway node has failed, determining, by said IMS CSCF, that said failure message comprises an indication that said failure is temporary based on a predetermined list of failure cause codes, and requesting, by said IMS CSCF, said gateway node, to retry to establish said bearer between said calling UE and said gateway node, or iii) receiving, by said IMS CSCF, a failure message thereby indicating that said bearer establishment between said calling UE and said gateway node has failed, determining, by said IMS CSCF, that said failure message comprises an indication that said failure is temporary based on a predetermined list of failure cause codes, and requesting, by said IMS CSCF, said calling UE to either retry to establish said Voice over Internet Protocol, VoIP, call between a calling User Equipment, UE, and said called UE via said radio access network, RAN, or to request said calling UE to re-register to said IMS network.