7.3 Policing Explained
Key Concepts
- Policing
- Traffic Shaping
- Rate Limiting
- Match Criteria
- Action Types
1. Policing
Policing is a traffic management technique used to enforce predefined traffic policies on a network. It ensures that network traffic adheres to specified rate limits and quality of service (QoS) requirements. Policing helps in maintaining network performance and preventing congestion.
Example: Think of policing as a traffic officer directing cars to ensure they do not exceed the speed limit. Just as the officer controls traffic flow, policing controls network traffic to maintain performance.
2. Traffic Shaping
Traffic shaping is a method of controlling the rate of traffic sent or received on a network interface. It involves delaying packets to ensure that the traffic stays within the defined limits. Traffic shaping helps in smoothing out traffic bursts and improving overall network efficiency.
Example: Consider traffic shaping as a traffic light system. Just as traffic lights regulate the flow of cars to prevent congestion, traffic shaping regulates data flow to prevent network congestion.
3. Rate Limiting
Rate limiting is the process of controlling the amount of traffic that can be sent or received over a network within a specific time period. It is used to prevent network overload and ensure fair usage of network resources. Rate limiting can be applied to individual users, applications, or entire network segments.
Example: Think of rate limiting as a water tap that controls the flow of water. Just as a tap limits the amount of water that can flow, rate limiting controls the amount of data that can be transmitted over the network.
4. Match Criteria
Match criteria are the conditions used to identify which traffic should be policed. These criteria can include parameters such as source and destination IP addresses, protocol types, and port numbers. Matching the correct traffic ensures that the policing rules are applied accurately.
Example: Consider match criteria as a filter that selects specific types of mail. Just as a filter selects mail based on certain criteria, match criteria select specific network traffic for policing.
5. Action Types
Action types define what happens to the traffic that matches the policing criteria. Common actions include dropping packets, marking packets with a lower priority, or allowing packets to pass without modification. The choice of action depends on the network policy and the desired outcome.
Example: Think of action types as different responses to a traffic violation. Just as a traffic officer can issue a warning, fine, or tow a car, action types can drop packets, mark them, or allow them to pass based on the network policy.