A communication system includes a programmable switch configured to perform packet transfer and queuing, a plurality of VNFs configured to execute network functions on packets, and a controller configured to control the programmable switch including a queue distribution unit configured to distribute input packets to any of the plurality of VNFs according to an instruction of the controller with respect to a queue group, the plurality of VNFs each include a load measurement unit configured to measure an amount of consumption of server resources and notify the controller of a load status, and the controller includes a load analysis unit configured to analyze a load of each of the plurality of VNFs based on a certain rule, and a queue control unit configured to change a queue distribution rule.