Packet Routing in Overlapping IPv4 Address Spaces
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Solution Overview
Problem
Current routing systems face challenges in correctly directing data packets between networks with overlapping IPv4 address spaces, leading to misrouting or packet drop, as they cannot distinguish between local and remote targets with identical addresses.
Innovation Solution
A method that analyzes outbound packets to determine whether the target address is local or remote, swapping an octet in the address if remote, and using address records and swapping rules to ensure correct routing through a gateway, with a swap-back mechanism for inbound packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard IP routing is used in overlapping address spaces, then routing simplicity is maintained, but packet misrouting and loss occur
Solution Approach 1:
The patent introduces a gateway as an intermediary device between networks with overlapping address spaces. The gateway performs address translation by swapping octets in IP addresses, acting as a mediator that resolves the ambiguity between local and remote targets with identical addresses. This intermediary mechanism enables reliable packet routing without requiring complex routing decisions at every network node.
Solution Approach 2:
The patent changes the parameter structure of IP addresses by swapping octets (e.g., transforming 10.2.3.4 to 2.10.3.4) when packets need to be routed to remote networks. This parameter transformation allows the routing system to distinguish between local and remote targets that would otherwise have identical addresses, resolving the routing ambiguity through modular address manipulation.
2Reliability
If address translation is performed for every packet, then routing accuracy in overlapping spaces is improved, but processing time increases
Solution Approach 1:
The patent implements preliminary action by pre-configuring routing tables with destination networks and corresponding octet swap rules before packet processing occurs. When a packet arrives, the system quickly matches the destination address against the pre-built routing table and applies the appropriate translation rule, avoiding the need for complex real-time analysis and reducing processing time while maintaining high routing accuracy.
3Adaptability or versatility
If octet swapping is applied to all packets, then remote packet routing is enabled, but local packets are incorrectly routed
Solution Approach 1:
The patent applies local quality by implementing different routing behaviors for local and remote packets based on their destination addresses. The system checks whether a packet's destination belongs to a local network or a remote network with overlapping addresses, and only applies octet swapping to packets destined for remote networks. Local packets are routed unchanged, ensuring that the gateway correctly distinguishes between the two cases and applies the appropriate translation only where needed.
Data Source
AI summary
At an outbound end of a tunnel from a first data network, a packet is analyzed to determine whether the packet is to be directed to a local target in the first data network or to be sent over the tunnel to a remote target in a second data network. A target address of the packet is present in both the first data network and the second data network. When the packet is to be directed to the remote target in the second data network, an octet in the target address of the packet is changed from a first value to a second value, the changing forming a modified packet. When the second value is stored in the octet, the modified packet is caused to be sent to the tunnel for delivery to the second data network.