Local area network uplink metropolitan area network and downlink multiple user terminals in a small area (such as the office building group of an enterprise), it has the characteristics of low distance requirement, large number of affiliated branches and diversified service access. The company's scheme has the following technical characteristics:

◆It has good scalability, the switching devices can achieve one-to-many, time-sharing connections between upstream sink links and downlink branch links or full-time interconnection of Arbitrary Two or Two in LAN, also can meet two-level switching cascade for more link switching.

◆Quantum key distribution duration of on-demand distribution link， and ensure the key supply of each user terminal.
Standardize application interface, do not affect the user's original business network architecture, support for encryption VPN and encryption router, support for multi - ◆service and multi - application terminal access, including the key filling of mobile application terminal.

◆Do not reduce connection rate and service quality, do not change users’ habits, do not degrade the user experience.  

The application scheme of local area network is shown in the following figure, which had been used for user access to multiple metropolitan area networks built by the company.