What model does the city library (Ningbo) core switch need? How many access points are there? Do you need to make redundant backups?
If there are about 48 access switches for so many points, then if they are all fully connected, 27 to 28 switches are enough. If each switch has spare space, it is necessary to plan how many access switches need to be connected according to the actual situation. The network can consider three-layer architecture, namely, access layer, convergence layer layer and core layer. Considering the cost, you can also choose two-layer structure to connect Huawei's 9700/ 12800, or choose H3C's 10500 and 12500 series.