6-1 IPv6 QoS Overview Explained
Key Concepts
IPv6 QoS (Quality of Service) Overview involves several key concepts:
- Classification
- Marking
- Queuing
- Policing and Shaping
- Congestion Management
1. Classification
Classification is the process of identifying and categorizing network traffic based on various criteria such as source and destination addresses, protocols, and ports. This helps in prioritizing different types of traffic.
Example: In a corporate network, VoIP traffic might be classified as high-priority, while file transfers are classified as low-priority. This ensures that critical communication is not disrupted by less important traffic.
2. Marking
Marking involves tagging packets with specific values that indicate their priority level. This tagging is done using Differentiated Services Code Point (DSCP) or Explicit Congestion Notification (ECN) bits in the IPv6 header.
Example: A VoIP packet might be marked with a DSCP value of 46 (EF - Expedited Forwarding), indicating that it should be given the highest priority in the network.
3. Queuing
Queuing is the process of managing the order in which packets are transmitted. Different queuing algorithms, such as Weighted Fair Queuing (WFQ) or Priority Queuing, are used to ensure that high-priority traffic is transmitted first.
Example: In a network with both video streaming and web browsing traffic, WFQ ensures that both types of traffic get a fair share of the bandwidth, while still prioritizing video streaming during congestion.
4. Policing and Shaping
Policing and shaping are techniques used to control the rate of traffic. Policing drops or marks packets that exceed a specified rate, while shaping delays packets to ensure they conform to the specified rate.
Example: A network might use policing to drop excess P2P traffic that exceeds a certain rate, while shaping ensures that critical business applications do not exceed their allocated bandwidth.
5. Congestion Management
Congestion management involves techniques to handle network congestion, such as Random Early Detection (RED) or Weighted RED (WRED). These techniques help in preventing congestion by dropping packets before the network becomes overloaded.
Example: WRED might be used to drop less important traffic (marked with lower DSCP values) before more important traffic, ensuring that critical applications remain unaffected during congestion.
Understanding these concepts is crucial for implementing effective IPv6 QoS. By mastering classification, marking, queuing, policing and shaping, and congestion management, you can ensure that your network provides the best possible service to critical applications and users.