NAT Device Address-Port-Borrowing Protocol

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Solution Overview

Problem

Multiple Network Address Translation (NAT) devices in a communication path hinder applications requiring incoming connections, such as VoIP and gaming, as the in-home NAT device's WAN address is not publicly routable when hidden behind a carrier NAT device, preventing direct connections between Internet users and hosts.

Innovation Solution

Implementing an address-port-borrowing-protocol in the in-home NAT device to communicate with the carrier NAT device to acquire and provide a publicly-routable transport address, enabling traversal through both NAT devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standard NAT traversal methods are used, then security is maintained and application compatibility is preserved, but direct connections between Internet users and hosts cannot be established when multiple NAT devices are in the communication path

Engineering Contradiction:
Improveconnection establishmentVSAvoidNAT device configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a STUN server as an intermediary to facilitate communication between hosts behind multiple NAT devices. The STUN server acts as a mediator that helps discover publicly routable addresses and establish direct connections without requiring complex configuration changes to the NAT devices themselves, thus resolving the contradiction between reliable connection establishment and device complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter of address discovery by using STUN protocols to dynamically obtain publicly routable addresses from carriers. This allows the system to adapt to different NAT configurations by changing how addresses are obtained rather than requiring changes to the NAT devices' fundamental operation, maintaining security while enabling direct connections

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the in-home NAT device provides its WAN address to hosts, then application compatibility is maintained, but the address is not publicly routable when hidden behind a carrier NAT device

Engineering Contradiction:
Improveaddress provision capabilityVSAvoidpublicly routable address information
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent applies preliminary action by having the STUN server proactively query the carrier NAT device before the host needs to establish a connection. This preliminary discovery of publicly routable addresses ensures that the necessary address information is obtained in advance, preventing loss of information when the in-home NAT device cannot provide directly routable addresses

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the STUN server receives responses from carrier NAT devices about publicly routable addresses and feeds this information back to the host. This feedback loop ensures that the host receives accurate, publicly routable address information even when the in-home NAT device's WAN address is not directly accessible, resolving the contradiction between address provision capability and information availability

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS8170014B1Multiple NAT traversal protocol
Publication Date: 2012.05.01 CISCO TECHNOLOGY INC

AI summary

Systems, methods, and other embodiments associated with multiple NAT traversal are provided. A request is received from a host for a publicly-routable communication path identifier for the host, where the host is a member of a private network associated with a first network address translation device. The first network address translation device communicates with a second network address translation device using an address-port-borrowing-protocol to acquire information related to the publicly-routable communication path identifier. Information related to the publicly-routable communication path identifier is received with the first network address translation device and the publicly-routable communication path identifier is provided to the host.