A network device coordinates with other devices in a network to create a
distributed filtering system. The device detects an attack in the
network, such as a distributed denial of service attack, and forwards
attack information to the other devices. The devices may categorize data
into one or more groups and rate limit the amount of data being forwarded
based on rate limits for the particular categories. The rate limits may
also be updated based on the network conditions. The rate limits may
further be used to guarantee bandwidth for certain categories of data.