Wired/wireless convergence network packet relay device and packet timestamp assigning method thereof

A timestamp assignment method of a packet of a network packet broker comprising:

• a software defined network (SDN) controller configured to acquire information on a plurality of OpenFlow edge switches being connected to a plurality of legacy networks as a wireless access network or a wired access network and belonging to a switch group;
• a legacy router container configured to consider a switch group including at least some of the plurality of switches as a virtual router and to generate routing information of a packet input to any one switch of the switch group;
• and
• a network application module configured to perform a function of controlling manipulation and flow of a packet in response to a request through the controller,
• wherein:
• the legacy router container maps a plurality of network devices connected to the plurality of OpenFlow edge switches for generating legacy routing information of a flow processing query message of the controller based on information on the at least one virtual router, to information of an external network connected directly to the virtual router;
• the network application module includes a time synchronization module configured to synchronize a packet time using a timestamp value of a network device;
• the network packet broker further includes a processor;
• the switch further includes a processor;
• the processor of the network packet broker includes a clock for replying with a time value;
• the processor of the switch includes a register configured to store a time parameter corresponding to a time that elapses from a reference time in the processor;
• and
• when the switch receives a request for assignment of a timestamp of a packet, the time synchronization module corrects overflow of the time parameter from the register of the processor of the switch of the reference time and stores the timestamp in the packet.