Push Keep-Alive Mechanism for SIP User Agents Behind NATs
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Solution Overview
Problem
In SIP deployment schemes, particularly in small office/home office (SOHO) scenarios, SIP devices behind network address translators (NAT) or firewalls face issues with inbound message blocking due to inactivity, leading to inefficient keep-alive mechanisms that drain battery power on wireless devices.
Innovation Solution
Implementing a 'push' keep-alive mechanism using non-SIP protocols like SMS, USSD, or IMS to notify SIP devices of incoming requests, triggering a ping request that unblocks SIP ports, allowing inbound messaging flows without continuous pinging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous pinging is used to maintain NAT/firewall connectivity, then connectivity is maintained, but battery power is drained excessively
Solution Approach 1:
The system uses periodic keep-alive messages instead of continuous pinging. The SIP user agent sends periodic REGISTER messages or other SIP keep-alive packets at defined intervals to maintain NAT/firewall connectivity, reducing energy consumption compared to continuous pinging while ensuring connectivity is maintained through periodic network activity.
2Use of energy by moving object
If periodic keep-alive messages are sent to maintain connectivity, then battery power consumption is reduced, but NAT/firewall blocking may still occur during inactivity periods
Solution Approach 1:
The system performs preliminary actions by sending periodic keep-alive messages before the NAT/firewall inactivity timeout occurs. By maintaining periodic network activity, the system preemptively prevents the NAT/firewall from blocking ports due to detected inactivity, ensuring connectivity is maintained without needing to react after blocking occurs.
Solution Approach 2:
The patent uses intermediary mechanisms such as SIP REGISTER messages or keep-alive packets that act as mediators between the SIP user agent and the NAT/firewall. These intermediary messages carry signaling information that maintains the NAT binding and prevents firewall blocking, serving as a middle layer that manages the connectivity state without requiring continuous data transmission.
3Reliability
If non-SIP protocols like SMS or USSD are used for notifications, then NAT/firewall blocking is bypassed, but protocol complexity increases
Solution Approach 1:
The system uses non-SIP protocols like SMS or USSD as intermediary notification channels that bypass NAT/firewall blocking. These protocols serve as mediators that can deliver notifications through blocked channels, with the SIP user agent then translating or converting these notifications into appropriate SIP actions, managing the complexity at the application layer rather than requiring protocol changes throughout the system.
Data Source
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AI summary
A user equipment (UE) and method is provided having one or more components configured to receive a non-session initiation protocol (SIP) notification from a SIP entity and in response to send a ping request to the SIP entity, the one or more components further configured to receive a SIP request from the SIP entity. A network component and method is also provided that include one or more components configured to send a non-session initiation protocol (SIP) notification to a user equipment (UE) and to receive a ping request from the UE and further to send a SIP request to the UE.