NAT Mapping via Dual-Message Address Comparison
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Solution Overview
Problem
Real-time communications, such as videoconferencing, are challenging to implement on packet-based networks like IP networks without compromising security mechanisms, particularly due to Network Address Translation (NAT) devices that complicate address data translation, leading to difficulties in two-way streaming audio and video data communication.
Innovation Solution
A method involving a client sending a first message with its address to a server, followed by a dummy or mapper message with external address data, allowing the server to map network address translators by comparing internal and external address data, facilitating communication through NATs and potentially combined proxy devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NAT translation is used to provide security and share public IP addresses, then security is improved and address space utilization is improved, but two-way streaming communication capability deteriorates
Solution Approach 1:
The server performs preliminary actions by sending a setup message to the client before actual data transmission. This message triggers the client to send a mapper message through the NAT, allowing the server to obtain the translated external address in advance. This preliminary address mapping enables subsequent two-way streaming communication to work around the NAT translation barrier while maintaining security.
2Reliability
If NAT translates external address data in packets, then security is improved and address space sharing is improved, but address data consistency deteriorates
Solution Approach 1:
The system implements a feedback mechanism where the server sends a setup message to the client, which then sends a mapper message back through the NAT. The server compares the internal address (from the setup message) with the external address (from the mapper message) to obtain the NAT translation mapping. This feedback loop ensures the server has accurate address consistency information despite NAT translation.
3Reliability
If a proxy device is combined with NAT, then security is improved and protocol-specific control is improved, but communication complexity increases
Solution Approach 1:
The invention uses an intermediary approach by introducing a setup message and mapper message exchange as mediators between the client and server. These intermediary messages facilitate the establishment of address mapping without requiring complex modifications to the NAT or proxy devices themselves, thereby reducing communication complexity while maintaining security.
Data Source
AI summary
An exemplary method for mapping a network address translator on a packet based network that is between a client and a server comprises the steps of the client communicating a first message including a first client address to the server, the server extracting the first client address, and the server communicating a confirmation to the client including identifying data useful to identify the client to the server. Additional steps comprise the client communicating a mapper message to the server including the identifying data, the mapper message having external client address data when the server receives it, and the server extracting said identifying data and using it to identify the client. An additional step of comparing the external client address data to the first client address and using said comparison to map the one or more security devices is provided.