NAT Port Detection via Bubble and Detecting Packets

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Solution Overview

Problem

Existing methods fail to accurately detect the port through which a bubble packet passes in communications processing devices with non-sequential port allocation rules, such as Cone, Address Sensitive, and Port Sensitive types, leading to communication failures between devices.

Innovation Solution

An information processing device that transmits a bubble packet and a detecting packet to determine the port position, adjusting the detecting packet transmission method based on the type of communications processing device, ensuring accurate detection of the bubble packet transmission port regardless of the device type.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a bubble packet is transmitted through a communications processing device with non-sequential port allocation (Cone, Address Sensitive, or Port Sensitive types), then the port position cannot be accurately detected using existing methods, but communication establishment is required

Engineering Contradiction:

Improveport position detection accuracyVSAvoidcommunication establishment reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

A detecting packet is introduced as an intermediary tool to indirectly obtain the port position information. The detecting packet is transmitted through the communications processing device, and its transmission behavior (which ports are opened) reveals the port allocation rule type and the specific port position where the bubble packet passed through, enabling accurate detection without directly querying the NAT device

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of directly detecting the bubble packet's port position, the method inverts the approach by transmitting a detecting packet and observing which ports are opened in response. The port position is inferred from the detecting packet's transmission behavior rather than directly measuring the bubble packet's path, effectively solving the detection problem through reverse reasoning

Inventive Principle:

Principle #13The other way round (Inversion)

2Productivity

If port numbers are allocated non-sequentially (as in Cone type NAT with FIFO queue), then port reuse efficiency is improved, but port position detection accuracy deteriorates

Engineering Contradiction:

Improveport allocation efficiencyVSAvoidport position detection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system implements feedback by transmitting detecting packets and observing the resulting port openings. The detection device receives information about which ports were opened by the detecting packet, uses this feedback to determine the port allocation rule type, and subsequently calculates the bubble packet's port position based on the detected pattern, enabling accurate detection despite non-sequential allocation

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The method changes the detection parameter from direct port number sequencing to observing port opening behavior patterns. By monitoring which ports are opened in response to detecting packets and analyzing the temporal and spatial patterns of these openings, the system can infer the allocation rule type and determine port positions without relying on sequential numbering

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If a detecting packet is transmitted to detect port position, then port detection capability is improved, but device complexity increases

Engineering Contradiction:

Improveport detection capabilityVSAvoidcommunication protocol complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The detecting packet serves multiple functions: it probes the port allocation rule type (Cone, Address Sensitive, Port Sensitive), determines the specific port position, and validates the detection methodology. This single packet type performs what would otherwise require multiple different probe mechanisms, reducing overall system complexity while maintaining high detection capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7693160B2Information processing device, port detecting device, information processing method, port detecting method, and program

Publication Date: 2010.04.06 PANASONIC HOLDINGS CORP

AI summary

There is provided an information processing device comprising bubble packet transmitter for transmitting a bubble packet via communications processing device, detecting packet transmitter for transmitting a detecting packet via communications processing device, the detecting packet used for detecting a position of a bubble packet transmission port, the detecting packet being transmitted in a manner that a detecting packet transmission port in communications processing device where the detecting packet passes through becomes the same as or different from a bubble packet transmission port, depending on a type of communications processing device, and bubble packet transmission port detector for detecting a position of the bubble packet transmission port according to the detecting packet transmission port.