This paper proposes mechanisms for detecting and controlling high bandwidth aggregates in the network, which are subsets of traffic that cause congestion. The current Internet infrastructure lacks built-in protection mechanisms against such congestion, which can result from denial of service (DoS) attacks or flash crowds. The paper introduces two mechanisms: Local Aggregate-Based Congestion Control (Local ACC) and Pushback. Local ACC identifies and limits the throughput of high-bandwidth aggregates to protect other traffic. Pushback allows routers to request upstream routers to rate-limit traffic corresponding to the specified aggregates, preventing upstream bandwidth from being wasted on packets that will be dropped downstream. The paper discusses the challenges of detecting and identifying high-bandwidth aggregates, which can be composed of numerous low-bandwidth flows. It also addresses the issue of determining the appropriate rate limit for aggregates, ensuring that other traffic on the link is protected. Pushback is particularly useful in DDoS attacks, where the attack traffic is concentrated at a few upstream links, and can protect other traffic within the aggregate from the attack traffic. The paper also discusses the limitations of these mechanisms, including the potential for overcompensation when pushback is invoked for non-malicious events such as flash crowds. It emphasizes that these mechanisms are not substitutes for adequately provisioning links or for end-to-end congestion control. The paper concludes that aggregate-based congestion control (ACC) could provide important protection against flash crowds, DDoS attacks, and other forms of aggregate-based congestion.This paper proposes mechanisms for detecting and controlling high bandwidth aggregates in the network, which are subsets of traffic that cause congestion. The current Internet infrastructure lacks built-in protection mechanisms against such congestion, which can result from denial of service (DoS) attacks or flash crowds. The paper introduces two mechanisms: Local Aggregate-Based Congestion Control (Local ACC) and Pushback. Local ACC identifies and limits the throughput of high-bandwidth aggregates to protect other traffic. Pushback allows routers to request upstream routers to rate-limit traffic corresponding to the specified aggregates, preventing upstream bandwidth from being wasted on packets that will be dropped downstream. The paper discusses the challenges of detecting and identifying high-bandwidth aggregates, which can be composed of numerous low-bandwidth flows. It also addresses the issue of determining the appropriate rate limit for aggregates, ensuring that other traffic on the link is protected. Pushback is particularly useful in DDoS attacks, where the attack traffic is concentrated at a few upstream links, and can protect other traffic within the aggregate from the attack traffic. The paper also discusses the limitations of these mechanisms, including the potential for overcompensation when pushback is invoked for non-malicious events such as flash crowds. It emphasizes that these mechanisms are not substitutes for adequately provisioning links or for end-to-end congestion control. The paper concludes that aggregate-based congestion control (ACC) could provide important protection against flash crowds, DDoS attacks, and other forms of aggregate-based congestion.