A communication network system including a hybrid network, said hybrid network including a network formed of a packet network which aggregates packets from a user and a wavelength network which cuts through traffic between packet switches, and a communication device, said communication device being connected to said packet network and said wavelength network, said communication device comprising: an optical switching unit which executes switching on a wavelength basis, said optical switching unit configured to transfer in-band control information to be exchanged on an in-band of said packet network with other communication device through a virtual control link which is an out-of-band IP control line generated on an IP control network for controlling said wavelength network and exchange said in-band control information with other communication device; a packet switching unit which executes switching on a packet basis, said packet switching unit configured to determine whether to generate a new connection, said new connection being a connection through said wavelength network between the communication device and said other communication device, for said wavelength network based on said in-band control information to be exchanged; and an IP control unit which controls said optical switching unit and said packet switching unit, said IP control unit configured to generate a new connection for said wavelength network in response to an instruction from said packet switching unit, wherein said packet switching unit, when receiving said in-band control information including an ACK returned from said other communication device having received said in-band control information, refers to an IP address of said other communication device to determine to generate the new connection for said wavelength network between said communication device and said other communication device. an optical switching unit which executes switching on a wavelength basis, said optical switching unit configured to transfer in-band control information to be exchanged on an in-band of said packet network with other communication device through a virtual control link which is an out-of-band IP control line generated on an IP control network for controlling said wavelength network and exchange said in-band control information with other communication device; a packet switching unit which executes switching on a packet basis, said packet switching unit configured to determine whether to generate a new connection, said new connection being a connection through said wavelength network between the communication device and said other communication device, for said wavelength network based on said in-band control information to be exchanged; and an IP control unit which controls said optical switching unit and said packet switching unit, said IP control unit configured to generate a new connection for said wavelength network in response to an instruction from said packet switching unit, wherein said packet switching unit, when receiving said in-band control information including an ACK returned from said other communication device having received said in-band control information, refers to an IP address of said other communication device to determine to generate the new connection for said wavelength network between said communication device and said other communication device.