Consistent and Fine-Grained Rule Update with In-Network Control for Distributed Rate Limiting

Coexisting applications contend for limited WAN bandwidth when communicating over distributed data centers in private clouds. Online service providers deploy distributed rate limiting systems to dynamically estimate each application instance’s bandwidth demand, and update rate limiting rules to provide performance isolation and bandwidth guarantees for applications with different priorities. However, the isolation violation caused by the inconsistent update of rate limiting rules among servers would eventually violate the Service Level Agreement requirements. Motivated by the observation that InNetwork Control can update rate limiting rules consistently with ultra-low latency for hundreds of thousands of end-hosts through in-band control messages, this paper presents DistRL, a dynamic distributed rate limiting system that can achieve fine-grained consistent updates. The main idea of DistRL is to replace the traditional controller with programmable switches to improve communication efficiency, thereby achieving finer-grained consistent updates. The evaluation shows that DistRL can support sub-second distributed updates of rate limiting rules without isolation violation for O(105) servers.