Delay Control with Programmable Data Planes

This thesis looks into the topic of "Delay Control with Programmable Data Planes". The primary focus is on exploring the potential of programmable switches, specifically BMv2 switches programmed with the P4 language. By investigating the operations that can be performed inside switch pipelines, the thesis aims to provide a deeper understanding of how to control the delay of packets in the network. Through our attempts, we observed that recirculation within the programmable switch is a potential method for controlling packet delays across the network. In the following, I developed packet recirculation within programmable switches. Based on the development of packet recirculation, this study investigates the effect of different recirculation iterations on packet delay. Additionally, we explore the broader consequences of this packet recirculation approach on network throughput. Initially, we conducted experiments in a controlled virtual environment. To enhance the depth of our insights, we extend our experimentation to real scenarios, employing a Linux server. This dual approach enables us to figure out the variations in outcomes between experiments in virtual and real Linux environments. The research employs Mininet, a network emulator, within the virtual Linux environment (Ubuntu) and the real Linux server to emulate a simple network topology. The topology consists of a source host, a destination host, and one or a chain of BMv2 switches. Programmable switches offer flexibility and programmability in their data plane, which consists of forwarding tables, flow tables, and packet processing capabilities. These switches enable customized forwarding decisions based on defined rules and match fields such as addresses, ports, or protocol types. The control plane, managed by a controller, plays a vital role in configuring and orchestrating the behavior of the programmable switches. By leveraging the flexibility and programmability of these switches, we can manage forwarding decisions or do other actions, adapt to dynamic network conditions, and achieve our goal. To evaluate the delay of packets and the performance of the network, experiments are conducted considering variations in the link parameters and configurations. For changing link parameters, a traffic controller tool within the Mininet is utilized. Throughput measurements are performed using the widely used IPERF tool, which supports both UDP and TCP protocols. Network delay is measured using the ping utility, which calculates round-trip times between the source and a specified destination. These measurements, along with the utilization of tcpdump, which is a packet analyzer, provide valuable insights into the effects of packet recirculation on network performance. The findings from this research contribute to enhancing the understanding of data plane programmability, how we can use recirculation in it to control the delay of packets, and the impacts of this on network performance, specifically throughput.