CoBit: A Cooperative Bit-Based Layer-4 Load Balancer for Mobile Edge Computing

Offloading computation tasks to Mobile Edge Computing (MEC) is a common practice for service providers, which requires Load Balancers (LB) to route packets to different devices. Current load balancers face significant scalability challenges due to increasing traffic loads in MEC environments, as well as limited and costly resources. In this paper, we propose CoBit(<bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Co</b>operative <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Bit</b>-based), a scalable layer-4 load balancer that reuses existing mid or low-end switches to achieve higher performance cooperatively. CoBit leverages a bit-based cooperative scheme to achieve routing with checking different partial bits of five-tuples in packet headers. CoBit can dramatically reduce the load on any single device and improve robustness against rapid changes in rules. For balanced load distribution with CoBit, we formulate the bit allocation across switches. We then propose dynamic programming-based algorithms for two MEC network scenarios: a linear topology and a multi-edge topology. We also address the challenge of limited SRAM in switches by developing a heuristic algorithm that optimally partitions bits of rules while ensuring that storage constraints are met. Finally, we conduct extensive evaluations with real-world MEC topologies and traffic datasets, demonstrating that CoBit performs much better than the previous rule-based LB scheme.