PGW IPv6-IPv4 Interworking via NAT64 DNS ALG Translation
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Solution Overview
Problem
The transition from IPv4 to IPv6 is complicated by the lack of interoperability between the two protocols, requiring mapping or translation to enable IPv6-only clients to access IPv4 networks and services, and existing solutions often necessitate modifications to the Policy and Charging Rule Function (PCRF) and Application Function (AF) in the Packet Data Network Gateway (PGW).
Innovation Solution
The system and method implement IPv6 and IPv4 mapping within the PGW functionality using NAT64 Domain Name System (DNS) Application-Level Gateway (ALG) translation, allowing the PGW to allocate both IPv4 and IPv6 addresses to users and perform address translation without modifying the PCRF or AF, thereby enabling seamless communication between IPv6-only clients and IPv4 networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If NAT64 DNS ALG translation is implemented within PGW functionality, then IPv6-only clients can access IPv4 networks, but device complexity increases
Solution Approach 1:
The patent combines NAT64, DNS ALG, and address translation functionalities within the existing PGW device. By merging these protocols and functions into a single network element, the system enables IPv6-to-IPv4 translation without requiring separate dedicated devices, thus improving adaptability while managing device complexity through consolidation.
Solution Approach 2:
The PGW is designed to perform multiple functions simultaneously: it acts as a Policy and Charging Rule Function gateway, a NAT64 translator, and a DNS ALG. This multi-functionality allows the single device to handle both IPv4 and IPv6 traffic, providing universal access capability across different IP versions without requiring separate specialized devices.
2Adaptability or versatility
If address translation between IPv6 and IPv4 is implemented, then communication between IPv6-only clients and IPv4 networks is enabled, but the transition complexity increases
Solution Approach 1:
The PGW functions as an intermediary device between IPv6-only clients and IPv4 networks. It performs address translation and protocol conversion, acting as a mediator that enables communication between the two incompatible IP versions without requiring modifications to either the IPv6 clients or the IPv4 network infrastructure.
Solution Approach 2:
The system creates translated copies of packets during the translation process. When an IPv6 packet needs to reach an IPv4 destination, the PGW creates a translated copy with IPv4 headers and addressing. This copying approach enables protocol conversion while maintaining the original IPv6 traffic flow for reference and potential reverse translation.
3Adaptability or versatility
If modifications are made to PCRF or AF to enable IPv6-IPv4 mapping, then protocol translation is achieved, but ease of operation decreases
Solution Approach 1:
The patent extracts the address translation functionality from the PCRF and AF components and relocates it to the PGW. By taking out the NAT64 and DNS ALG functions from the policy and application layers and placing them in the gateway layer, the system achieves protocol mapping capability without requiring modifications to the PCRF or AF, thereby maintaining ease of operation.
Data Source
AI summary
A Packet Data Network Gateway (PGW) network node of an Evolved Packet Core (EPC) for interfacing with an IP Multimedia Core Network Subsystem (IMS) comprises an IP address assignment functionality module configured to assign both IPv4 and IPv6 addresses to a User Equipment (UE) requesting an IPv6 address, a Network Address Translation-Application Layer Gateway (NAT64-ALG) functionality module and PGW configured to translate between IPv4 and IPv6 addresses, a Gx interface toward a Policy Control and Charging Rules Function (PCRF) network node configured to transmit the UE's IPv4 address to the PCRF, and an SGi interface toward an application node of the IMS configured the UE's IPv4 address to the application node, and to transmit and receive IP media packets between the IMS and the UE after IPv4 and IPv6 address translation.