(The network design of small and medium-sized enterprises meets the requirements of the group's informatization, and provides convenient and fast information paths for various systems; it has good performance and can support various uses of large capacity and real-time; it can operate reliably and has a low Failure rates and maintenance requirements. Provide a network security mechanism to meet the requirements of the group's information security, with high cost performance, easy future upgrades and expansions, and protect user investment; users are simple to use, easy to maintain, and provide users with good after-sales service.)