网络链接

集线器、交换机、路由器、中继器及网关、网桥之间的区别

http://blog.csdn.net/lx85416281/article/details/53234154

点到点通信和端到端通信

https://www.zhihu.com/question/49245486

http://bestkuan.blog.51cto.com/939332/212008/

减脂运动

https://www.zhihu.com/question/27987054