Server-Driven NAT Keep-Alive for Mobile Power Conservation
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Solution Overview
Problem
Conventional keep-alive techniques for network address translation (NAT) devices, particularly in battery-powered mobile devices, consume excessive power and generate unnecessary wireless activity to maintain connections, as they require frequent packet transmissions to prevent timeout expiration.
Innovation Solution
A server-driven keep-alive mechanism that sends keep-alive messages with a time-to-live value set to terminate at the NAT device, eliminating the need for mobile devices to process or respond to these messages, thereby reducing power consumption and network traffic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional keep-alive techniques are used to prevent NAT timeout, then connection stability is maintained, but battery power is excessively consumed and wireless activity increases
Solution Approach 1:
The patent extracts the keep-alive function from the mobile device and relocates it to the server. The server sends keep-alive packets to the NAT device without requiring the mobile device to participate in transmission or response, thereby eliminating the energy consumption and wireless activity while maintaining connection stability
Solution Approach 2:
The NAT device serves as an intermediary that receives keep-alive packets from the server and processes them to refresh connection state. The mobile device is removed from the keep-alive exchange entirely, acting only as the original connection initiator while the server-NAT interaction maintains the connection
2Reliability
If mobile devices transmit keep-alive packets to maintain connections, then connection activity is maintained, but network traffic increases
Solution Approach 1:
The mobile device is extracted from the keep-alive packet transmission process. Only the server transmits keep-alive packets to the NAT device, eliminating the bidirectional traffic that would otherwise occur when mobile devices send and receive keep-alive packets
Solution Approach 2:
Instead of the mobile device initiating keep-alive packets (client-to-server direction), the server initiates keep-alive packets (server-to-NAT direction). This inversion eliminates the need for mobile device transmission while achieving the same connection maintenance goal
Data Source
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AI summary
Keep-alive processing for NAT devices and reducing power consumption in wireless clients. A server driven keep-alive mechanism facilitates keep-alive messages to a NAT device currently providing a connection to a mobile client to refresh the NAT state, thereby reducing or eliminating power consumption in a wireless device to respond to the connection with keep-alive packets. In one instance, keep-alive packets are sent to the NAT device to reset the NAT timeout timer, and then to the mobile client. The client responds only when expected keep-alive packets are not received at the client. In another instance, keep-alive packets reset the NAT timer to maintain the connection but are dropped or self-destruct before reaching the mobile client thereby providing the optimum power conservation in the mobile device. Thus, the client is not forced into extra client activity to send or receive wireless data, thereby draining the battery.