Difference between Traffic Policing and Traffic Shaping

Traffic Policing and Traffic Shaping are two fundamental network traffic management techniques used to control bandwidth utilization and ensure Quality of Service (QoS) in computer networks. Both methods help regulate data flow but use different approaches to handle excess traffic.

Traffic Policing

Traffic Policing is a network monitoring technique that enforces traffic rate limits by taking immediate action against packets that exceed predetermined rates. It uses a token bucket mechanism where tokens represent bytes of data that can be transmitted.

When traffic exceeds the configured rate, policing drops or marks the excess packets rather than queuing them. This approach provides strict enforcement of bandwidth contracts but can result in packet loss during traffic bursts.

Traffic Shaping

Traffic Shaping is a bandwidth management technique that controls traffic flow by buffering and delaying packets to conform to a specified traffic profile. Unlike policing, shaping queues excess packets and releases them at a controlled rate.

This method smooths traffic bursts and reduces packet loss by temporarily storing excess packets in buffers. Traffic shaping only controls outbound traffic and introduces controlled delay to maintain consistent data flow rates.

Key Differences

Common Use Cases

Traffic Policing is commonly used at network edges for service provider interfaces, rate limiting, and enforcing SLA agreements. Traffic Shaping is typically deployed on WAN interfaces, where bandwidth is limited and smooth traffic flow is crucial for optimal performance.

Conclusion

Traffic Policing enforces strict rate limits by dropping excess packets, while Traffic Shaping smooths traffic flow by buffering and delaying packets. The choice between them depends on whether packet loss or delay is more acceptable for your network requirements.