(http://pic.dhe.ibm.com/infocenter/zos/v1r12/topic/com.ibm.zos.r12.halu101/dwgl0004.gif)
http://www.cs.northwestern.edu/~agupta/cs340/project2/TCPIP_State_Transition_Diagram.pdf (http://www.cs.northwestern.edu/~agupta/cs340/project2/TCPIP_State_Transition_Diagram.pdf)