Inline NAT in Mobile Gateway Router
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Solution Overview
Problem
Current network address translation (NAT) solutions in mobile access networks face challenges in efficiently managing millions of concurrent subscriber sessions, often requiring external NAT devices and impacting throughput, while also being limited by the availability of public network addresses and port ranges.
Innovation Solution
Implementing inline NAT within the forwarding plane of a mobile gateway router, where session management cards pre-allocate public network addresses and port ranges for subscribers, and a forwarding integrated circuit performs network address translation, allowing dynamic port selection and binding for each subscriber session, thereby reducing dependency on external NAT devices and enhancing scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external NAT devices are used to translate private addresses to public addresses, then network address translation can be performed, but system complexity increases and throughput decreases
Solution Approach 1:
The patent combines the NAT function with the mobile gateway router by integrating a NAT table and translation logic into the existing routing infrastructure. The router maintains a NAT table that maps private subscriber addresses to public addresses, and the forwarding plane performs address translation during packet forwarding operations, eliminating the need for separate external NAT devices and reducing overall system complexity.
Solution Approach 2:
The mobile gateway router is designed to perform multiple functions simultaneously: routing packets based on destination addresses, translating private addresses to public addresses using NAT, and managing subscriber sessions. By making the router multi-functional, the patent eliminates dedicated NAT hardware and reduces system complexity while maintaining NAT functionality.
2Reliability
If external NAT devices are used for address translation, then NAT can be performed, but processing throughput is reduced
Solution Approach 1:
By merging NAT operations with the router's packet forwarding plane, the patent enables address translation to occur in parallel with routing decisions. The NAT table is optimized for fast lookup using hardware acceleration, allowing millions of packets per second to be translated without becoming a bottleneck, thus maintaining high throughput while providing reliable NAT functionality.
3Adaptability or versatility
If public network addresses are allocated dynamically, then address availability is improved, but management complexity increases
Solution Approach 1:
The patent implements pre-allocation of public address pools for different subscribers or service types. During session establishment, the router assigns addresses from pre-configured pools rather than performing complex real-time allocation. This preliminary organization of address resources simplifies management while maintaining the flexibility to dynamically assign addresses as needed.
Solution Approach 2:
The NAT table and address allocation mechanism are designed to be dynamically adjustable. The router can modify NAT entries, add or remove address mappings, and adapt to changing network conditions without requiring complete reconfiguration. This dynamic capability provides address allocation flexibility while keeping management complexity manageable through automated processes.
Data Source
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AI summary
Techniques are described for performing inline NAT functions in a forwarding element of a mobile gateway router or other device in which subscriber sessions of a mobile access network are distributed across a plurality of session management cards. The session management cards pre-allocate a public network address and port range for subscribers at the time a network connection is established in response to connection request prior to receiving any data traffic associated with the subscriber. NAT profiles are programmed into hardware forwarding elements of the mobile gateway router for inline NAT when routing subscriber traffic for the mobile access network.