GGSN Direct Tunnel Error Handling via Intermediary Routing
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Solution Overview
Problem
In packet-switched networks, especially with direct tunnel functionality, error handling is inadequate when a radio network controller fails, leading to data packets being lost as the serving GPRS support node (SGSN) is not informed, causing context preservation issues and delayed re-establishment of radio access bearers.
Innovation Solution
The gateway GPRS support node (GGSN) stores the IP-address and TEID of the SGSN and RNC, rerouting subsequent packets to the SGSN instead of the RNC upon error indication, and includes additional information elements in update messages to facilitate direct tunnel establishment and re-establishment, reducing signaling load and time delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If direct tunnel functionality is implemented to establish direct user plane connection between RNC and GGSN, then data transmission speed is improved and SGSN signaling overhead is reduced, but error handling capability deteriorates when RNC fails because SGSN is not informed of the failure
Solution Approach 1:
The patent introduces GGSN as an intermediary that receives error indications from RNC and forwards them to SGSN. This mediator resolves the contradiction by enabling error notification to SGSN without requiring SGSN to be directly involved in the error handling path, thus maintaining both fast direct tunnel data transmission and reliable error handling capability
Solution Approach 2:
The patent segments the error handling function into two parts: RNC sends error indications to GGSN, and GGSN forwards them to SGSN. This segmentation allows the direct tunnel to maintain fast data transmission while the segmented error path ensures reliable notification reaches SGSN without affecting the direct tunnel performance
2Device complexity
If direct tunnel is established between RNC and GGSN, then signaling load on SGSN is reduced, but ability to detect and measure errors deteriorates since SGSN lacks error information
Solution Approach 1:
GGSN acts as an intermediary that collects error indications from RNC and relays them to SGSN. This allows SGSN to maintain reduced signaling load while still receiving comprehensive error information through the intermediary GGSN, resolving the contradiction between signaling reduction and error detection capability
Solution Approach 2:
The patent establishes a feedback mechanism where error indications flow from RNC to GGSN and then to SGSN. This feedback loop ensures SGSN receives error information without increasing its signaling load, as the feedback is routed through GGSN which already has the error data from direct tunnel operations
3Reliability
If error indication is sent directly from RNC to SGSN in traditional architecture, then error handling is reliable, but data transmission speed and signaling efficiency are reduced due to SGSN involvement in all user plane operations
Solution Approach 1:
GGSN serves as an intermediary that receives error indications from RNC and forwards them to SGSN. This maintains the reliability of error handling by ensuring SGSN receives error information, while simultaneously enabling direct tunnel data transmission between RNC and GGSN that does not require SGSN involvement, thus achieving both reliable error handling and fast data transmission
Solution Approach 2:
The patent extracts the user plane data transmission path from SGSN involvement, creating a direct tunnel between RNC and GGSN. Error handling reliability is maintained by extracting only the necessary error notification function and routing it through GGSN to SGSN, separating error signaling from data transmission paths
Data Source
AI summary
An apparatus is disclosed which according to an embodiment is configured to store a direct tunnel context. The direct tunnel context comprises a field or flag indicating whether or not a direct tunnel is established between the apparatus and a radio network, and further comprises at least one of a tunnel endpoint identifier and an address of a user plane of a serving node. The direct tunnel context optionally further comprises at least one of a tunnel endpoint identifier and an address of a user plane of a controller of the radio network. The apparatus may be a gateway or a gateway general packet radio service support node. The invention further provides a method, system, device and program suitable or configured to handle such direct tunnel contexts.