The recent decades have witnessed vast development in communication world; especially in internet technology that has played a vital role in moving forward the human communications, with such development user stress better communication services such as video conferencing. Video conferencing becomes more admired nowadays since it breaks the constraints on the communication ways of people who are probably exist in diverse geographical locations. SIP is preferred to be used as signaling protocol for video conferencing, but still using SIP for video conferencing is affected by delay. This work aimed to study the performance of SIP signaling for video conferencing and describing the causes of delay in SIP establishment and termination. There are two studies in this book, the first is carried out by using ns-2 to simulate transport protocols and study their effect. The second is carried out by using SIPp to achieve two objects. The first is to study the relationship between number of simultaneous calls on the session establishment and termination, while the second is to verify the result of changing transport modes of transport protocol for both session establishment and termination.