With the deep deployment of 4G network all over the world, 5G network has been started. Compared with 4G, 5G network needs to support multiple services and application scenarios ：

1） eMBB （Enhanced Mobile Broadband）

2） mMTC（Massive Machine-Type Communication）

3） uRLLC（Ultra Reliable & Low Latency Communication）

These application scenarios bring new challenges to the reliability, real-time and capacity of wireless networks. C-RAN（Centralized, Cooperative, Cloud and clean RAN）is a new access network supporting centralized wireless signal processing in the cloud. It further divides BBU functions into CU (central unit) and DU(distributed unit). In this way, it can effectively reduce the cost of network construction, reduce the demand for supporting wireless station location, facilitate the rapid deployment of stations, and maintain the competitive advantage of the network.

In the construction of C-RAN, the centralized deployment of CU causes the high consumption of transmission resources in the fronthaul network, which leads to the high cost of laying a large number of optical cables and the long construction period. Therefore, it is urgent to find a more effective fronthaul solution.

SONT provides two solutions to this problem:
(1）Bidi:bidirectional (bidi) technology can save 50% fiber resources and provide performance guarantee for high-precision synchronous transmission. Sont 25G SFP28 BIDI optical transceivers include SR，LR industrial-temperature series with features of using LC Receptacles, IEEE802.3by and SFF-8472 Compliant, Low Power Consumption, Small Size, High-speed and Wide Temperature Range.

(2）WDM：Using color optical transceivers on BBU / DU and AAU with WDM (CWDM / DWDM / LAN WDM) ODU/OMU device, can greatly save the consumption of optical fiber resources. . Sont WDM provide 6λ/12λ/18λ/24λ ODU/OMU with Low Power Consumption, Small Size, Waterproof and Dust-proof ;25G SFP28 optical transceivers include CWDM/DWDM/Lan-WDM industrial-temperature series with features of using LC Receptacles, IEEE802.3by and SFF-8472 Compliant, Low Power, Small Size, Wide Temperature Range.