and hardware. Virtualized data centers may also apply rate limiting at the hypervisor layer. Two important performance metrics of rate limiters in data centers are resource footprint (memory and CPU usage) which determines scalability, and precision. There usually exists a trade-off, that is, higher precision can be achieved by dedicating more resources to the rate limiters. A considerable body of research with focus on improving performance of rate limiting in data centers. See also Bandwidth management Bandwidth throttling Project Shield Algorithms Token bucket Leaky bucket Fixed window counter Sliding window log Sliding window counter Libraries ASP.NET Web API rate limiter ASP.NET Core rate limiting middleware Rate limiting for .NET (PCL Library) Rate limiting for Node.JS References Network performance