## 1 Introduction
TCP (Transport Control Protocol) [8] and UDP (User Datagram Protocol) [9] for real-time transportation of video have been shown to be ineffective. As is further reviewed in Section 2, TCP is best used for lossless data transfer as it ensures packet delivery by its support of packet retransmission. This poses a problem for real-time traffic, as there is no time for retransmission [10]. UDP is better for video traffic, but unfortunately still cannot guarantee real-time and loss performance. RTP (Real-Time TransportProtocol) [11] offers an alternative but has other shortcomings that need to be remedied, as is discussed later. Most of the aforementioned transport algorithms and the traffic control protocols below are built on top of TCP and have only been tested in wired networks. Quite often, packets in a wireless network are stored in a buffer waiting for proper bandwidth allocation before they can be delivered. In real-time communication, a poorer quality can be tolerated, but delay should be reduced to a minimum if not eliminated. Since a large volume of video traffic can easily consume the limited wireless bandwidth, there is a need to throttle the video traffic for better bandwidth utilization and avoid congestion. Traffic/Congestion control can provide smooth throughput and high link utilization for real-time data. Of the two main types of traffic congestion, control in computer networking (reviewed in Section 2), implicit congestion control does not provide smooth throughput for real-time and low link utilization. Also, the control is based on packet loss-events which are not a big concern for real-time traffic as mentioned earlier. Explicit congestion control of traffic from the router node becomes impractical in a high speed when the CPU cannot catch up with the updating of events arising from changing driving speeds. Consequently, a different protocol (desirably with a low complexity) should be considered. Finally, it is safer and more cost efficient to simulate possible solutions than actual field experimenting with highway driving. An effective VANET simulation platform/model has pertinent importance in research and industry to emulate a real world situation. One major challenge is the development of an effective platform that can bring all issues described earlier under one simulation model. A major issue is the integration of an effective mobility model that considers vehicle-to-vehicle interaction and vehicle-to-infrastructure interaction along with the full functionalities of a communication device capable of effective receiving, processing and transmitting capabilities. Although there has been work on creating a similar platform, e.g., [12, 13, 14], little work has been done on certain issues related to video streaming from vehicle camera such as the characterization of the data traffic (e.g., its unique packet size distribution) and the behavior under different driving conditions (e.g., highway _vs._ local). In view of the above and others reviewed in the related work in the next section, we seek to create a robust platform for effective VANET simulation, one that can provide an environment to test, develop and deploy effective communication protocols that would enhance real-time communication of video information from vehicle camera. As forerunners, in this paper, we would like to:  
1. create a real-time camera video model under VANET conditions;
2. integrate a realistic VANET mobility model to test the testbed at various speeds;
3. integrate a practical algorithm to survive network congestion;
4. demonstrate the capability of such a platform. To achieve the above objectives, we first adopt the protocol architecture of our simulation platform as shown in Figure 1. We need to adopt appropriate protocols for the lower layers consisting of the Data Link Layer and the Physical Layer, and the upper layers for the remainder.