An apparatus for and a method of integrating switching and transferring of synchronous optical network/synchronous digital hierarchy (SONET/SDH), plesiochronous digital hierarchy (PDH), and Ethernet signals, which integrate and provide connection of synchronous digital (SONET/SDH) signals, plesiochronous digital (PDH) signals, and Ethernet signals, mutually change the synchronous digital (SONET/SDH) signals, the plesiochronous digital (PDH) signals, and the Ethernet signals, packet switching, synchronous timeslot switching, and channel configuration management and control functions in one system. Thus, packet switching capacity, timeslot switching capacity, and packet/timeslot bridging capacity can be enlarged and configured according to corresponding application. Also, a distinctive service compared to a service provided by a separate Ethernet device or a SONET/SDH network device can be provided through a packet/timeslot bridge. In addition, varied and reliable communication service at a moderate price can be provided to service users, and decreased investment and maintenance fee can be provided to carrier service providers.