Abstract: A communication system includes: a first forwarding apparatus located at an end point of a network, a second forwarding apparatus located at an end point of the network, and a control apparatus that constructs a virtual network by controlling the first and second forwarding apparatuses. The control apparatus sets in the first forwarding apparatus, a first processing rule such that, when the first forwarding apparatus receives a packet into which is inserted a first tag including an identifier for identifying the virtual network, the first forwarding apparatus inserts a second tag into the received packet and sends the received packet from a prescribed port. The control apparatus sets, in the second forwarding apparatus, a second processing rule such that, when the second forwarding apparatus receives the packet into which is inserted the second tag, the second forwarding apparatus removes the second tag and sends from a prescribed port.

Abstract: A flow processing apparatus in a Q-in-Q model may receive frames having different IVIDs but the same sender MAC address, in which case a MAC duplication problem occurs in the flow processing apparatus. A communication system according to an embodiment of the present invention includes: a flow processing apparatus that transmits a MAC duplication notification indicating an occurrence of MAC duplication in a case in which a plurality of frames received from different ports and belonging to a predetermined virtual network have the same sender MAC address; and a flow control apparatus that changes the configuration of the predetermined virtual network in a case in which the MAC duplication notification has been received from the flow processing apparatus.

Abstract: A communication system includes: a first forwarding apparatus located at an end point of a network, a second forwarding apparatus located at an end point of the network, and a control apparatus that constructs a virtual network by controlling the first and second forwarding apparatuses. The control apparatus sets in the first forwarding apparatus, a first processing rule such that, when the first forwarding apparatus receives a packet into which is inserted a first tag including an identifier for identifying the virtual network, the first forwarding apparatus inserts a second tag into the received packet and sends the received packet from a prescribed port. The control apparatus sets, in the second forwarding apparatus, a second processing rule such that, when the second forwarding apparatus receives the packet into which is inserted the second tag, the second forwarding apparatus removes the second tag and sends from a prescribed port.