A distributed software defined network, SDN, packet core system comprising: at least one cloud-based centralized SDN infrastructure instance including a subscriber module for authenticating client devices communicating with the SDN packet core system; and a plurality of interconnected local SDN infrastructure instances, each local SDN infrastructure instance including a plurality of computer devices arranged geographically in proximity, and communicatively coupled, to a respective plurality of radio access points associated with at least two radio access technologies, RATs, the computer devices for each local SDN infrastructure instance being configured to execute software modules for processing control messages and data packets of communication flows associated with the respective radio access points, the software modules include: for each local SDN infrastructure instance, a plurality of RAT-specific control-plane modules associated with the at least two radio access technologies, RATs, each RAT-specific control-plane module configured to execute signaling and control operations for communication flows associated with a respective RAT; and for each local SDN infrastructure instance, a plurality of data-plane instances separated from the plurality of RAT-specific control-plane modules, the plurality of data plane instances configured to process data packets associated with communication flows served by the local SDN infrastructure instance, wherein each of the plurality of data plane instances includes a collection of packet processing engines, at least one collection of packet processing engines includes respective protocol-specific processing elements configured to perform RAT-specific network functions associated with at least two RATs. at least one cloud-based centralized SDN infrastructure instance including a subscriber module for authenticating client devices communicating with the SDN packet core system; and a plurality of interconnected local SDN infrastructure instances, each local SDN infrastructure instance including a plurality of computer devices arranged geographically in proximity, and communicatively coupled, to a respective plurality of radio access points associated with at least two radio access technologies, RATs, the computer devices for each local SDN infrastructure instance being configured to execute software modules for processing control messages and data packets of communication flows associated with the respective radio access points, the software modules include: for each local SDN infrastructure instance, a plurality of RAT-specific control-plane modules associated with the at least two radio access technologies, RATs, each RAT-specific control-plane module configured to execute signaling and control operations for communication flows associated with a respective RAT; and for each local SDN infrastructure instance, a plurality of data-plane instances separated from the plurality of RAT-specific control-plane modules, the plurality of data plane instances configured to process data packets associated with communication flows served by the local SDN infrastructure instance, wherein each of the plurality of data plane instances includes a collection of packet processing engines, at least one collection of packet processing engines includes respective protocol-specific processing elements configured to perform RAT-specific network functions associated with at least two RATs. for each local SDN infrastructure instance, a plurality of RAT-specific control-plane modules associated with the at least two radio access technologies, RATs, each RAT-specific control-plane module configured to execute signaling and control operations for communication flows associated with a respective RAT; and for each local SDN infrastructure instance, a plurality of data-plane instances separated from the plurality of RAT-specific control-plane modules, the plurality of data plane instances configured to process data packets associated with communication flows served by the local SDN infrastructure instance, wherein each of the plurality of data plane instances includes a collection of packet processing engines, at least one collection of packet processing engines includes respective protocol-specific processing elements configured to perform RAT-specific network functions associated with at least two RATs.