Asymmetric vs. Symmetric Routing

Asymmetric Routing –  convenient but with limitations

In asymmetric routing, traffic to and from a network takes different paths. This is common in large-scale internet environments due to the complex nature of network routing. While this method is characterized by its simplicity and cost-effectiveness and can be efficient for normal operations, it poses significant challenges during DDoS attacks. The main issue is that only inbound traffic is typically monitored and scrubbed, which can lead to incomplete mitigation and potential security loopholes.

Advantages of Asymmetric Routing:

• Simplicity in Deployment – quick setup, often becoming operational within hours.
• Cost-Effectiveness – features lower subscription and operational costs.
• Flexibility in Traffic Management – allows clients to independently manage outgoing traffic, choosing routes that minimize delays.
• Reduced Latency – delivers traffic with minimal delay, enhancing performance.

Despite these benefits, asymmetric routing exhibits vulnerabilities, particularly against sophisticated DDoS attacks like TCP Reflection and Random UDP floods. These attacks exploit the stateless nature of this method, often bypassing the basic filters applied.

Disadvantages of Asymmetric Routing:

• Vulnerability to Complex Attacks – asymmetric routing struggles against multi-vector DDoS attacks that require analysis of both incoming and outgoing traffic patterns.
• Potential for False Positives – without analyzing outgoing traffic, distinguishing between legitimate requests and attack vectors becomes challenging, increasing the risk of blocking valid traffic.
• Limited Visibility – offers a partial view of traffic patterns, which might lead to inadequate threat detection and response.
• Regulatory Challenges – may not meet compliance requirements for industries mandating complete data inspection.

Symmetric Routing – comprehensive and secure

Symmetric routing ensures that traffic to and from a network travels the same path. This approach is advantageous during DDoS mitigation because it allows for comprehensive analysis of both inbound and outbound traffic. By examining the entire traffic flow, symmetric routing enables a more accurate differentiation between legitimate requests and malicious data, enhancing the overall security posture. Symmetric routing addresses the limitations of asymmetric methods enhancing the detection and mitigation of sophisticated DDoS attacks while not impacting the clean traffic.

Why Symmetric Routing is Essential for Effective DDoS Mitigation

At Path Network, we emphasize the importance of symmetric routing for several reasons:

• Enhanced Traffic Analysis – symmetric routing allows our DDoS mitigation systems to perform stateful inspections of all traffic. This means we can maintain the context of network sessions, which is crucial for identifying and mitigating complex attack patterns, such as TCP reflection attacks and sophisticated UDP floods.
• Accurate Anomaly Detection – by analyzing how traffic behaves both entering and leaving the network, we can identify discrepancies that may indicate a DDoS attack more reliably. This dual-point analysis reduces false positives and ensures that legitimate traffic is not mistakenly blocked.
• Global Stateful Synced Firewall – our global stateful firewall, enhanced by our patented hole-punching technology, benefits immensely from symmetric routing. This setup ensures that return traffic for outbound connections is efficiently managed, allowing for dynamic adjustment of firewall rules based on real-time traffic analysis.

CoreTech Implementation of Symmetric Routing

CoreTech infrastructure is designed to support robust symmetric routing capabilities across our 20 global Points of Presence (PoPs). This design allows us to disperse attack traffic geographically, mitigating the impact on any single location and providing redundancy and resilience across the network.

Our advanced traffic flow analytics further benefit from symmetric routing, allowing our network operations centers (NOCs) to monitor and respond to threats in real-time. This capability is crucial for maintaining the uptime and reliability that our clients expect.

Conclusion

The choice between asymmetric and symmetric routing has significant implications for DDoS mitigation effectiveness. At CoreTech, our commitment to symmetric routing reflects our dedication to providing the highest level of security and performance. By continuously advancing our technologies and methodologies, we ensure that our clients receive not only state-of-the-art protection but also a strategic advantage in their network operations.

For more insights into our network security solutions and how we can help safeguard your operations, visit our website or contact our expert team directly at [email protected] or [email protected]