Patent ID: 7995463

Claim:
A transmission device comprising: a synchronous transmission network interface section; a switch section connected to said synchronous transmission network interface section; and first and second LAN interface sections respectively connected to said switch section, wherein said first LAN interface section includes: a de-mapping section for de-mapping a signal which is inputted from said switch section and in which packets are mapped and thereby obtaining packets from the signal; a distribution section for distributing the packets obtained in said de-mapping section to first and second paths; a transmission and reception section that transmits and receives packets to and from a packet network and includes a first transmission and reception port for transmitting the packets arriving through said first path to a packet network; and a mapping section that maps into said signal both of the packets received from said packet network through said first transmission and reception port and the packets distributed to said second path, and then sends the signal to said switch section, wherein said second LAN interface section includes: a de-mapping section that de-maps said signal which is inputted from said switch and in which the packets from said packet network are mapped and said signal in which the packets distributed to said second path are mapped, then sends to a third path the packets distributed to said second path and sends to a fourth path the packets from said packet network; a transmission and reception section that transmits and receives packets to and from said packet network and includes a second transmission and reception port for transmitting the packets arriving through said third path to said packet network; a collection section for collecting the packets received from said packet network through said second transmission and reception port and the packets sent to said fourth path; and a mapping section for mapping into said signal the packets collected by said collection section and then sending the signal to said switch section, and wherein when no failure is present in both of said first and second LAN interface sections, said switch section transfers said signal received from a synchronous transmission network by said synchronous transmission network interface section to the de-mapping section of said first LAN interface section, transfers both of said signal which is inputted from the mapping section of said first LAN interface section and in which the packets from said packet network are mapped and said signal in which the packets distributed to said second path are mapped to the de-mapping section of said second LAN interface section, and transfers said signal inputted from the mapping section of said first LAN interface section to said synchronous transmission network interface section.