CGN Bypass Gateway for Dynamic Inbound Traffic Access

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Solution Overview

Problem

Internet Service Providers (ISPs) face challenges in efficiently managing network address translation (NAT) due to the exhaustion of IPv4 addresses, leading to impractical solutions like Carrier Grade NAT (CGN), which often block inbound traffic and require costly static IP addresses.

Innovation Solution

A system and method that provides a bypass for Carrier Grade NAT (CGN) by using a gateway with a NAT router to assign private IP addresses and map them to public IP addresses using 1:1 NAT rules, allowing inbound access to specific devices like webcams, while dynamically managing public IP addresses for non-bypass devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If Carrier Grade NAT (CGN) is implemented to address IPv4 address exhaustion, then the number of customers served is improved, but inbound traffic is blocked and applications requiring unique public IP addresses do not work properly

Engineering Contradiction:

Improvenumber of customers servedVSAvoidinbound traffic support

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent segments the customer base into two groups: those requiring 1:1 NAT with public IP addresses and those using NAPT. The system dynamically assigns customers to appropriate NAT modes based on their service requirements, allowing inbound traffic support for specific customers while maintaining address conservation for others.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic NAT mode assignment where customers can transition between NAPT and 1:1 NAT modes based on their needs. The system dynamically allocates public IP addresses from a pool when customers require inbound access, and releases them when no longer needed, making the NAT approach flexible rather than static.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If conventional NAT is used to allow inbound initiated access, then inbound traffic works properly, but the number of public IP addresses required exceeds available addresses

Engineering Contradiction:

Improveinbound traffic supportVSAvoidnumber of public IP addresses required

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent recovers public IP addresses by releasing them from customers who no longer require 1:1 NAT mode, making them available for allocation to other customers who do require inbound access. This continuous allocation and release cycle maximizes the utilization of limited public IP address resources.

Inventive Principle:

Principle #34Discarding and recovering

3Adaptability or versatility

If static IPv4 addresses are provided to customers for unique public IP address assignment, then inbound access and application compatibility are improved, but the cost increases significantly

Engineering Contradiction:

Improveinbound traffic supportVSAvoidservice cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent enables customers to self-select or self-configure their NAT mode requirements. Customers who need inbound access can request 1:1 NAT mode through the system, and the system automatically allocates public IP addresses from the shared pool, eliminating the need for ISPs to provision expensive dedicated static IP addresses to each customer.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent creates a universal public IP address pool that serves multiple functions: it supports both NAPT for address conservation and 1:1 NAT for customers requiring inbound access. The same pool of addresses is dynamically shared between different customer groups based on their current needs, providing multi-functionality without requiring separate address pools.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP3398302B1Method and system of providing carrier grade NAT (CGN) to a subset of subscriber base

Publication Date: 2022.05.11 HUGHES NETWORK SYST

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AI summary

A method and system are disclosed for providing a service to bypass carrier grade NAT (CGN). A first and second range of private IPv4 addresses are generated for mapping to public IPv4 addresses. Subscribers to the service are provided terminals with a status code which indicates its status with respect to the service. The terminal is assigned a private IP subnet within the first range of private IPv4 addresses, if the status code is indicative of a bypass status and the terminal identifies a bypass device that requires access to inbound traffic from the public network. Each bypass device is assigned a private IPv4 address from the first range, and the bypass device's private IPv4 address is mapped to a public IPv4 address. Inbound traffic having a matching public IPv4 destination address is subsequently directed to the bypass device.