AFTR Flow Label Extraction for Overlapping IPv6 NAT
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Solution Overview
Problem
In the IPv6 evolution, when multiple links between a gateway and an AFTR correspond to the same tunnel for network address translation, overlapping or identical IP addresses of customer premise equipment cause the AFTR to fail in distinguishing different terminal users, resulting in packet feedback issues.
Innovation Solution
The method involves receiving IPv6 or IPv4 packets, obtaining flow labels corresponding to link identities of customer premise equipment, decapsulating or encapsulating packets accordingly, and performing network address translation to differentiate terminal users, ensuring correct packet forwarding even with overlapping IP addresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple links between gateway and AFTR correspond to the same tunnel for network address translation, then network address translation can be performed, but terminal users with overlapping or identical IP addresses cannot be distinguished
Solution Approach 1:
The patent introduces a new dimension for user identification by utilizing the Flow Label field in IPv6 packets. Instead of relying solely on IP addresses (which may overlap), the system extracts and uses Flow Label values as an additional distinguishing dimension. This allows the AFTR to differentiate between multiple terminal users even when their IP addresses are identical or overlapping, thereby resolving the identification problem without affecting the tunnel-based NAT functionality.
2Adaptability or versatility
If IP addresses of customer premise equipment are overlapping or the same, then network configuration becomes simpler, but the AFTR cannot distinguish different terminal users
Solution Approach 1:
The patent introduces Flow Label as an intermediary element that mediates between the simplified IP address allocation (which allows overlaps) and the need for accurate user distinction. The Flow Label field acts as a mediator that carries additional identification information without interfering with the IP address structure, enabling both flexible IP allocation and precise user identification to coexist.
3Adaptability or versatility
If tunnel encapsulation is used for IPv4 over IPv6, then IPv4 packets can be transmitted over IPv6 network, but packet feedback cannot be properly delivered to terminal users
Solution Approach 1:
The patent implements a feedback mechanism by extracting the Flow Label from the IPv6 packet header and using it to identify the original terminal user. This enables the AFTR to properly route feedback packets back to the correct user by matching the Flow Label in the feedback packet with the stored Flow Label-user correspondence. This feedback mechanism ensures that responses and acknowledgments are delivered to the correct terminal users even when multiple users share the same tunnel and IP address space.
Data Source
AI summary
The embodiments of the present invention provide a method, a device, and a system for forwarding a packet. The method includes: receiving an IPv6 packet sent by a gateway, and obtaining a flow label of the IPv6 packet, where the flow label of the IPv6 packet is corresponding to a link identity of customer premise equipment in one-to-one correspondence; decapsulating the IPv6 packet; performing network address translation on a decapsulated packet according to the flow label; and forwarding the decapsulated packet according to a translated network address. When multiple links between the gateway and an AFTR are corresponding to the same tunnel for network address translation, in the case that IP addresses of terminal users are overlapping or are the same, different terminal users can be distinguished, so that a terminal user that sends a packet can receive feedback, thus improving customer satisfaction.