Passive aggregation-layer network device, network system, and working method therefor

A network system, wherein the network system comprises a core-layer network device, a passive aggregation-layer network device, a first access-layer network device, and a second access-layer network device, wherein the passive aggregation-layer network device comprises:

• a first multiplexer/demultiplexer comprising:
• a first optical interface connected to an optical module of the first access-layer network device, and
• a second optical interface connected to an optical module of the second access-layer network device;
• a second multiplexer/demultiplexer comprising:
• a third optical interface connected to a first optical module of the core-layer network device, and
• a fourth optical interface connected to a second optical module of the core-layer network device;
• and
• a first optical fiber connecting the first multiplexer/demultiplexer with the second multiplexer/demultiplexer;
• wherein the first multiplexer/demultiplexer is configured to receive a first optical signal sent by the optical module of the first access-layer network device and a second optical signal sent by the optical module of the second access-layer network device, couple the first optical signal and the second optical signal to obtain a first coupled optical signal, and send the first coupled optical signal to the second multiplexer/demultiplexer by using the first optical fiber;
• and
• the second multiplexer/demultiplexer is configured to decouple the first coupled optical signal to obtain the first optical signal and the second optical signal, send the first optical signal to the first optical module of the core-layer network device, and send the second optical signal to the second optical module of the core-layer network device.

A working method for a passive aggregation-layer network device, wherein the passive aggregation-layer network device comprises a first multiplexer/demultiplexer, a second multiplexer/demultiplexer, and a first optical fiber connecting the first multiplexer/demultiplexer with the second multiplexer/demultiplexer, the first multiplexer/demultiplexer is connected to an optical module of a first access-layer network device and an optical module of a second access-layer network device, the second multiplexer/demultiplexer is connected to a first optical module and a second optical module of a core-layer network device, and the working method for the passive aggregation-layer network device comprises:

• receiving, by the first multiplexer/demultiplexer, a first optical signal sent by the optical module of the first access-layer network device and a second optical signal sent by the optical module of the second access-layer network device, coupling the first optical signal and the second optical signal to obtain a first coupled optical signal, and sending the first coupled optical signal to the second multiplexer/demultiplexer by using the optical fiber;
• and
• decoupling, by the second multiplexer/demultiplexer, the first coupled optical signal to obtain the first optical signal and the second optical signal, sending the first optical signal to the first optical module of the core-layer network device, and sending the second optical signal to the second optical module of the core-layer network device.