Interaction between Control and Data Planes The widespread use of the Internet as well as its potential for disruptive effects on both business and society has made the Internet one of the most important communication infrastructures. All IP services (including domain name service or DNS, web hosting, and email) depend on connectivity that is built on the routing infrastructure. The Internet traffic has exhibit increasing variability in both data plane and control plane. In data plane, malicious attacks such as worm or virus scan can impact the dynamics of the traffic, while in control plane, both malicious attacks and unintentional misconfigurations can impact the stability and reliability of the Internet. Router performance under variable data and control traffic load is critical for understanding the robustness and performance of the Internet infrastructure. Variablity of data traffic: How does the variablity of data traffic impact the performance of routers? The variablity includes packet size, packet interarrival time, and packet type. Systematic studies of potential variablity can further facilitate the understanding of variablity of control plane as described below. Variablity of control plane traffic: The variablity of control plane traffic (generated by both interdomain and intradomain routing protocols) can be caused by attacks on either data plane or control plane. For example, evidences have shown that worm traffic has caused BGP session reset or router reboot, which in turn leads to large variablity on control plane. Further, unintentional human errors or intentional misconfigurations can lead to persistent variablity on control plane. Although large scale exploitation of routers has not been reported yet, the potential impact of these attacks can be so large that preventive measures must be taken in the near future. Interaction between control and data plane traffic: The instability of control plane can further impact the performance of data plane. Updating routing and forwarding tables consumes a large number of CPU cycles when there is a significant amount of routing update traffic. This might lead to significant performance degradation of data forwarding, in particular to low-end routers. Further, to what extent can the instability of control plane impacts delay, loss on data plane? Are loops caused by transit behavior of routing protocols or misconfiguration?