Media Session Handover via LAN Profile NAT Detection
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Solution Overview
Problem
Existing methods for handover of active media sessions, such as voice calls, between heterogeneous IP networks face challenges like gaps or delays in audio due to IP address changes, especially when moving between different networks like WiMax and WiFi, and are complicated by Network Address Translation (NAT) routers and firewalls, which can block or alter packets.
Innovation Solution
The solution involves determining the type of NAT routers or firewalls present in both the network and the corresponding node, and using specific handover procedures based on these determinations to minimize disruptions, such as using STUN techniques to identify public IP addresses and ports, and implementing media control channels like RTCP to monitor and improve audio quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mobile device changes IP address when moving between heterogeneous IP networks (e.g., WiMax to WiFi), then the device can access different networks and maintain connectivity, but audio gaps or delays occur in active media sessions
Solution Approach 1:
The system performs preliminary detection of NAT router types and firewall configurations before handover occurs. By pre-evaluating the network environment and determining the appropriate handover procedure in advance, the system prepares the necessary packet translation rules and routing information before the IP address change, thereby minimizing audio gaps and maintaining media session continuity during network switching
Solution Approach 2:
The system introduces an intermediary mechanism that intercepts and translates packets during handover. When a mobile device changes networks and IP addresses, the intermediary translates packets between the old and new IP addresses, ensuring continuous delivery of media data without gaps or delays, thus resolving the conflict between network adaptability and session reliability
2Object-affected harmful factors
If NAT routers and firewalls are used to protect networks, then network security is improved, but packet blocking or alteration occurs that complicates handover procedures
Solution Approach 1:
The system dynamically changes packet parameters such as IP addresses, ports, and protocol types based on the detected NAT router type and firewall configuration. By adapting packet parameters to match the specific network environment, the system can traverse different NAT and firewall configurations without requiring complex manual configuration, thus reducing handover procedure complexity while maintaining security
Solution Approach 2:
The system implements dynamic handover procedures that automatically adjust to different NAT and firewall configurations. Instead of using static, one-size-fits-all handover methods, the system dynamically detects the network environment and selects appropriate translation rules and routing strategies, thereby simplifying the overall handover process while maintaining network security
3Speed
If standard handover procedures are used without considering NAT types, then handover can be performed quickly, but audio quality deteriorates due to packet blocking or improper routing
Solution Approach 1:
The system performs preliminary detection of NAT router types and firewall configurations before handover occurs. By pre-evaluating the network environment and determining the appropriate handover procedure in advance, the system prepares the necessary packet translation rules and routing information before the IP address change, thereby minimizing audio gaps and maintaining media session continuity during network switching
Solution Approach 2:
The system introduces an intermediary mechanism that intercepts and translates packets during handover. When a mobile device changes networks and IP addresses, the intermediary translates packets between the old and new IP addresses, ensuring continuous delivery of media data without gaps or delays, thus resolving the conflict between network adaptability and session reliability
Data Source
AI summary
Methods and systems are provided for efficient handover of a media session between heterogeneous Internet Protocol (IP) networks. A mobile device with Internet access can operate a software program to communicate with a corresponding node. The corresponding node may access the Internet through either a Network Address Translation (NAT) router or a firewall. The mobile device establishes a media session with a corresponding node via the transmission of a first media stream and receipt of a second media stream, and a media control channel can optionally be implemented. The mobile device can acquire Internet access through a second IP address, and packets routed between the second IP address and the Internet may traverse a NAT router. The mobile device can evaluate the type of NAT at the second IP address from a stored Local Area Network (LAN) profile. A software routine can determine that handover of the media session from the first IP address to the second IP address is preferred. A software routine can determine efficient handover procedures according to Network handover rules. The mobile device may begin transmitting a third media stream to the corresponding node and the corresponding node can transmit a fourth media stream to the second IP address. A media control channel is optionally supported.