A mobile core network including a mobile core network entity providing access and mobility management functions and a mobile core network entity providing gateway control plane functions, wherein: - the mobile core network entity providing access and mobility management functions is configured to send a request to initiate the release of an established connectivity for a user equipment when no service that is interrupted at internet protocol address change of the user equipment, referred to as sensitive service, is on-going on said established connectivity, wherein said request is sent upon detection of a need for gateway relocation optimization, said gateway relocation optimization including said initiation of the release of said established connectivity when no sensitive service is on-going, - the mobile core network entity providing gateway control plane functions is configured to receive said request, - the mobile core network entity providing gateway control plane functions is configured to, after receiving said request, monitor the user plane traffic over said established connectivity to detect the absence of on-going sensitive service, and to initiate the release of said established connectivity before re-establishing a connectivity, for the user equipment, when absence of on-going sensitive service is detected, wherein the established connectivity is a PDN connection, the mobility core network entity providing access and mobility management functions is an MME/SGSN and the mobility core network entity providing gateway control plane functions is a PGW, or wherein the established connectivity is a PDU session, the mobility core network entity providing access and mobility management functions is an AMF and the mobility core network entity providing gateway control plane functions is an SMF. - the mobile core network entity providing access and mobility management functions is configured to send a request to initiate the release of an established connectivity for a user equipment when no service that is interrupted at internet protocol address change of the user equipment, referred to as sensitive service, is on-going on said established connectivity, wherein said request is sent upon detection of a need for gateway relocation optimization, said gateway relocation optimization including said initiation of the release of said established connectivity when no sensitive service is on-going, - the mobile core network entity providing gateway control plane functions is configured to receive said request, - the mobile core network entity providing gateway control plane functions is configured to, after receiving said request, monitor the user plane traffic over said established connectivity to detect the absence of on-going sensitive service, and to initiate the release of said established connectivity before re-establishing a connectivity, for the user equipment, when absence of on-going sensitive service is detected, wherein the established connectivity is a PDN connection, the mobility core network entity providing access and mobility management functions is an MME/SGSN and the mobility core network entity providing gateway control plane functions is a PGW, or wherein the established connectivity is a PDU session, the mobility core network entity providing access and mobility management functions is an AMF and the mobility core network entity providing gateway control plane functions is an SMF.