A communication system includes at least one node that processes a packet, and a control device that receives a request for a transmission of a first processing rule from said node, the first processing rule including a matching rule and a second processing rule that conforms to the matching rule, the matching rule being for comparing with information included in the packet. The control device retrieves a first processing rule which corresponds to an identifier from a database if the identifier for identifying the first processing rule is included in the request.