A network communication system comprising: a communication device configured to access a communication network by using an access ID, to retain a flow table on which at least one flow entry is registered, and to operate said flow table; and a controller communicatively connected to said communication device, wherein said controller is configured such that: when said flow entry includes a match condition and an action, said action designates packet processing that is performed with respect to a received packet belonging to said flow entry matching said match condition, and said communication device is configured to execute said action of said flow entry to said received packet, and to retain flow access ID information indicating a correspondence relationship between each flow of said flow table and access ID; and said controller is configured such that when initiating communication of a new flow, said communication device is configured to transmit an allocation request to said controller, wherein said allocation request is for determination of an access ID to be used; said controller is configured to determine, in response to said allocation request, an allocated access ID to be used regarding said new flow and to notify said communication device of allocation information indicating a correspondence relationship between said new flow and said allocated access ID; said communication device is configured to register, in accordance with said allocation information, the correspondence relationship between said new flow and said allocated access ID on said flow access ID information; said communication device is configured to refer to said flow access ID information and uses said allocated access ID corresponding to said new flow to access said communication network; and wherein said access ID is an SSID required for connecting to an access point of a wireless LAN. a communication device configured to access a communication network by using an access ID, to retain a flow table on which at least one flow entry is registered, and to operate said flow table; and a controller communicatively connected to said communication device, wherein said controller is configured such that: when said flow entry includes a match condition and an action, said action designates packet processing that is performed with respect to a received packet belonging to said flow entry matching said match condition, and said communication device is configured to execute said action of said flow entry to said received packet, and to retain flow access ID information indicating a correspondence relationship between each flow of said flow table and access ID; and said controller is configured such that when initiating communication of a new flow, said communication device is configured to transmit an allocation request to said controller, wherein said allocation request is for determination of an access ID to be used; when said flow entry includes a match condition and an action, said action designates packet processing that is performed with respect to a received packet belonging to said flow entry matching said match condition, and said communication device is configured to execute said action of said flow entry to said received packet, and to retain flow access ID information indicating a correspondence relationship between each flow of said flow table and access ID; and said controller is configured such that when initiating communication of a new flow, said communication device is configured to transmit an allocation request to said controller, wherein said allocation request is for determination of an access ID to be used; said controller is configured to determine, in response to said allocation request, an allocated access ID to be used regarding said new flow and to notify said communication device of allocation information indicating a correspondence relationship between said new flow and said allocated access ID; said communication device is configured to register, in accordance with said allocation information, the correspondence relationship between said new flow and said allocated access ID on said flow access ID information; said communication device is configured to refer to said flow access ID information and uses said allocated access ID corresponding to said new flow to access said communication network; and wherein said access ID is an SSID required for connecting to an access point of a wireless LAN.