อ้างอิง

OSI Model

http://osimode01.weebly.com/osi-model-7-layer.html

http://lakkycomputernetwork.blogspot.com/2010/06/osi-model-7-layer.html

http://goo.gl/VjEUrj

http://www.freewebs.com

http://www.ismed.or.th

Protocol 

http://goo.gl/vScZEt

http://goo.gl/QoLLkH

http://goo.gl/aLVZja

http://goo.gl/W3VuxP

http://dhcpserver.weebly.com/dhcp-36273617363436183606363835913629363236523619.html

http://cht-jomz.blogspot.com/2015/07/arp.html

http://sumatty.blogspot.com/

https://sites.google.com/site/icmp03/structure-icmp/hlak-kar-thangan