spanning-tree portfast 可以讓終端設備快速連上網路 出處:http://smalleaf.blogspot.com/2011/10/switch-bpdu-guard.html https://dotblogs.com.tw/box5068/2011/01/19/20892
http://admitlove2.pixnet.net/blog/post/81195293-%E8%B7%A8vlan%E5%9F%BA%E7%A4%8E%E8%A8%AD%E5%AE%9A
