trafficshaping

Traffic shaping is a network traffic management technique that regulates the flow of data packets to conform to a specified bandwidth profile. By delaying excess packets within short time windows, shaping smooths traffic bursts and prevents sudden congestion. It is part of broader quality of service (QoS) strategies and is distinct from traffic policing, which typically drops or marks packets that exceed a limit rather than delaying them.

In practice, shaping operates by placing traffic into queues and enforcing rate limits using mechanisms such as token bucket or leaky bucket algorithms. Routers, switches, and dedicated devices implement shaping for both ingress (incoming) and egress (outgoing) traffic. Policy can define per-user, per-application, or per-destination rules, prioritizing latency-sensitive applications (such as voice and video) and deprioritizing bulk transfers.

Common scheduling disciplines include class-based queuing (CBWFQ), priority queuing, weighted fair queuing (WFQ), and round-robin variants. Shaping can create predictable bandwidth and reduced jitter, aiding service level agreements and user experience on networks with variable demand. However, it can introduce additional latency, may be circumvented by traffic bursts, and requires careful monitoring to avoid unintentional starvation of other traffic.

In regulated environments, traffic shaping is used by Internet service providers and enterprises to manage limited capacity, enforce fair usage, and meet performance targets. Its use intersects with policy considerations such as net neutrality and acceptable use policies, which vary by jurisdiction and organization.