SDN-Based DDoS Defense via Dynamic IP Assignment

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Solution Overview

Problem

Conventional DDoS defense systems are flawed as they allow attackers to bypass protection by revealing the protected host's IP address, leading to black hole routing that discards legitimate user access traffic along with attack traffic, rendering services inaccessible to intended users.

Innovation Solution

Implementing a Software Defined Network (SDN) with separate control and data planes to dynamically assign multiple public network addresses for protected hosts, ensuring legitimate traffic is routed through a different address than the targeted by attackers, thereby preventing black hole routing from affecting legitimate user access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If black hole routing is used to filter DDoS attack traffic, then attack traffic is blocked, but legitimate user traffic is also discarded

Engineering Contradiction:
ImproveDDoS attack traffic blockingVSAvoidservice availability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system segments traffic into attack traffic and legitimate traffic using SDN-based flow classification, allowing differential routing where attack traffic is blocked and legitimate traffic is forwarded to the protected host

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The SDN controller acts as an intermediary between the routing device and the protected host, dynamically assigning alternative public network addresses and generating forwarding paths to redirect legitimate traffic around the black hole routing

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If a single public network address is assigned to a protected host, then traffic management is simple, but the host becomes vulnerable to DDoS attacks

Engineering Contradiction:
Improvenetwork address managementVSAvoidDDoS attack vulnerability
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically assigns multiple public network addresses to the protected host based on attack detection, switching between addresses to evade DDoS attacks while maintaining simple address management through automated SDN control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the network address parameter dynamically by assigning alternative public network addresses when attacks are detected, allowing the protected host to escape attack traffic while maintaining service availability

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If dynamic multiple public network addresses are assigned, then DDoS attack resilience is improved, but network address management complexity increases

Engineering Contradiction:
ImproveDDoS attack resilienceVSAvoidnetwork address management
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system provides self-service through automated SDN controller management that dynamically assigns and manages multiple public network addresses without requiring manual intervention, reducing the perceived complexity for network administrators

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3485613B1Processing network traffic to defend against attacks
Publication Date: 2021.08.25 ALIBABA GROUP HOLDING LTD
  • EP3485613B1 patent drawingFigure 1
  • EP3485613B1 patent drawingFigure 2
  • EP3485613B1 patent drawingFigure 3

AI summary

Network traffic processing includes: determining whether one or more packets of network traffic associated with a first public network address have been dropped, the first public network address being associated with a target host; in response to the determination that the one or more packets associated with the first public network address have been dropped, assigning a second public network address to the network traffic and generating a forwarding path corresponding to the second public network address, wherein the second public network address is configured to receive the network traffic, and wherein the forwarding path is configured to forward the network traffic received at the second public network address to the target host; and notifying a filtering device to transmit the network traffic to the second public network address and cause the network traffic to be forwarded to the target host according to the forwarding path.