The transmission network is an important part of the communication network used for data communication between different network devices and provides support and service for the business network. The design of the transmission network structure is highly flexible, according to different application scenarios it can be designed in different structures. The structure of a typical 2G mobile communication network is shown in the figure below. The transmission network is divided into the backbone layer, convergence layer and access layer. Each level mainly uses a mesh topology.
The development of optical transmission networks has experienced the innovation and growth of Pseudo-synchronous Digital Hierarchy (PDH), Synchronous Digital Hierarchy (SDH), Multi-Service Transmission Platform (MSTP), Wavelength Division Multiplexing (WDM), Automatic Switching Optical Network (ASON) and Packet Transmission Network (PTN).
Data communication in the transmission network mainly uses optical fiber as the medium, and the connection between optical fiber and equipment requires different types of optical transceivers. According to different application scenarios, GrenTech provides 1.25G SFP 550m and 10km transceiver, 10G SFP+ 10km to 40km transceiver, 25G SFP28 10km transceiver and 100G QSFP28 CWDM4 and LR4 transceiver.