路由和交换机知识，收藏

https://blog.csdn.net/qq_38265137/article/category/7126126

vlan基础知识：https://blog.csdn.net/qq_38265137/article/details/80390759

接入层、汇聚层和核心层交换机的特点：https://blog.csdn.net/Linux7985/article/details/78838132