Reverse Forwarding Information Base Enforcement for Overlapping IP Networks
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Solution Overview
Problem
Current Internet routing protocols struggle to route packets between private networks due to overlapping IP address spaces, leading to unroutable addresses, and fail to meet emerging requirements such as dynamic Quality of Service, unified IPv4 and IPv6 routing, and secure, encrypted routing.
Innovation Solution
A method and system for managing stateful routing sessions by analyzing candidate interfaces for suitability as return paths, establishing sessions using suitable interfaces, and dropping sessions if no suitable interface is found, utilizing a reverse forwarding information base to determine interface suitability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If current Internet routing protocols are used to forward packets between private networks, then routing simplicity is maintained, but routing capability between private networks is lost due to overlapping IP address spaces
Solution Approach 1:
The patent introduces a reverse forwarding information base (RFIB) as an intermediary structure that mediates between private network routing requirements and public Internet routing constraints. The RFIB stores reverse path information that enables routers to determine suitable return paths for packets traversing private networks with overlapping address spaces, effectively acting as a mediator that resolves the routing conflict without requiring complex protocol modifications.
Solution Approach 2:
The patent applies preliminary action by pre-populating the reverse forwarding information base with reverse path information before routing decisions are needed. This advance preparation allows routers to quickly determine suitable return paths when private network packets need to be routed, eliminating the need for complex real-time calculations and enabling private network routing capability without adding operational complexity.
2Reliability
If stateful routing sessions are established without analyzing return path suitability, then session establishment speed is improved, but session reliability deteriorates due to inability to ensure suitable return paths
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing suitable return paths in the reverse forwarding information base before session establishment is attempted. When a session needs to be established, the router can quickly query the pre-populated RFIB to determine return path suitability, maintaining fast session establishment while ensuring reliability through advance verification of return path capabilities.
Solution Approach 2:
The patent implements feedback by using the reverse forwarding information base to provide information about return path suitability back to the session establishment process. This feedback mechanism allows the router to make informed decisions about whether to establish sessions based on pre-analyzed return path characteristics, ensuring reliable session establishment without significant time loss.
3Measurement precision
If reverse forwarding information base is used to analyze candidate interfaces for return paths, then routing precision is improved, but processing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the routing information into separate forward forwarding information base (FFIB) and reverse forwarding information base (RFIB) structures. This segmentation allows the system to maintain high precision in return path determination through the specialized RFIB while managing complexity by keeping the reverse path information separate from the primary forwarding logic, enabling independent optimization of each component.
Data Source
AI summary
A router determines whether or not to establish a stateful routing session based on the suitability of one or more candidate return path interfaces. This determination is made when a first packet for a new session arrives at the router on a given ingress interface. For example, the router may be configured to require the ingress interface be used for the return path of the session, and the router may evaluate whether the ingress interface is suitable for the return path and may drop the session if the ingress interface is unsuitable for the return path. In other examples, the router may be configured to not require that the ingress interface be used for the return path, and the router may evaluate whether at least one interface is suitable for the return path and drop the session if no interface is suitable for the return path.