OpenTrafficShaper is an opensource traffic shaping platform for Linux. Features include user, group and IP based shaping, traffic classes and radius integration.
Its designed to be extremely lightweight and bring a truly enterprise featureset to the Linux operating system. It is able to operate in under 40Mb RAM with 3,000 shaping classes configured. The underlying code has minimal external dependencies and highly optimized codepaths.
The hierarchy class-based shaping design and traffic classification is cleverly designed to allow for minimal recursion and quick matching of traffic flows for classification. The methods of shaping used have further been researched over the past 10 years and are based on thousands of deployments of similar solutions.