GGSN Direct Tunnel Mark Detection in PDP Context Updates
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Solution Overview
Problem
In the third generation mobile communication system, the Gateway GPRS Support Node (GGSN) cannot determine whether the Serving GPRS Support Node (SGSN) has started a direct tunnel, which is essential for proper error processing and resource management.
Innovation Solution
A direct-tunnel mark is set in the request message for updating the packet data protocol context to indicate if the SGSN has started a direct tunnel, allowing the GGSN to determine this by checking the mark and deciding whether to delete or reserve user plane tunnel information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the direct-tunnel scheme is implemented to reduce data delay, then transmission performance is improved, but the GGSN cannot determine whether the SGSN has started the direct tunnel, leading to improper error processing
Solution Approach 1:
A direct-tunnel mark is introduced as an intermediary indicator in the PDP context update request message. This mark serves as a mediator that conveys tunnel status information from the SGSN to the GGSN, enabling the GGSN to determine whether the direct tunnel is active without requiring complex signaling modifications.
Solution Approach 2:
The invention changes the parameter state of the PDP context update request message by adding a specific mark field. This parameter change allows the message to carry additional information about tunnel status, enabling the GGSN to distinguish between direct-tunnel and double-tunnel scenarios and process errors appropriately.
2Loss of information
If the PDP context update request message is modified to include direct-tunnel mark, then the GGSN can determine tunnel status, but the message structure becomes more complex
Solution Approach 1:
The tunnel status information is extracted as a separate mark field from the complex PDP context update request message structure. This extraction approach allows the essential information to be conveyed independently, minimizing the impact on overall message complexity while ensuring the GGSN receives the necessary tunnel status indication.
3Reliability
If the GGSN stores user plane tunnel information of the SGSN for future use, then error processing can be improved, but memory resources are consumed
Solution Approach 1:
The GGSN performs preliminary storage of the SGSN's user plane tunnel information when the direct-tunnel mark indicates the SGSN has deleted its local copy. This preliminary action ensures that if errors occur later, the GGSN has the necessary information available for proper error processing, while only storing information when actually needed rather than always.
Data Source
AI summary
A method for acquiring that SGSN (30) has started a direct tunnel by GGSN (40) in a packet domain is provided, the method comprises: a step of setting mark, wherein in a tunnel establishing process, SGSN sets a direct-tunnel mark in a request message of updating PDP context sent to GGSN (40) to indicate whether SGSN (30) has started the direct tunnel if SGSN (30) has started the direct-tunnel scheme; a step of determining mark, wherein GGSN (40) indicates that SGSN (30) has started the direct tunnel and acquires an address and user plane tunnel information of RNC (20) included in the request message of updating PDP context if GGSN (40) determines that the received request message of updating PDP context has the direct-tunnel mark. A system for acquiring that SGSN (30) has started a direct tunnel by GGSN (40) in a packet domain is provided, a mark setting module is added in SGSN (30), and a mark determining module is set in GGSN (40).