Session Restoration Flag for MBMS Network Failure Handling
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Solution Overview
Problem
Current communication network restoration procedures in eMBMS networks face challenges such as inability to adjust session parameters without absolute start time, leading to resource misallocation and service disruptions during failures like SGSN, MME, or MBMS-GW failures, especially when switching between control planes.
Innovation Solution
Incorporating a restoration flag, adjusted session duration parameter, and adjusted time to data transfer parameter in session start request messages across interfaces like Sn, Sm, and SGmb to facilitate seamless session restoration and resource optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If session restoration is attempted without a restoration flag, then the RAN node may reject the session start request message due to existing session conflicts, but adding a restoration flag increases message complexity and requires additional signaling
Solution Approach 1:
A restoration flag is introduced as an intermediary element in the session start request message. This flag acts as a mediator that communicates the restoration intent between CN nodes and RAN nodes, enabling the RAN node to distinguish between new session requests and restoration requests, thereby preventing unnecessary rejections while maintaining clear signaling through a simple binary indicator
2Reliability
If session parameters are not adjusted during restoration, then resource allocation may be optimized, but service disruption increases due to parameter mismatches after failures
Solution Approach 1:
Session parameters such as session duration and time to data transfer are dynamically adjusted during the restoration process. The CN node modifies these parameters in the session start request message to reflect current network conditions and failure context, ensuring that the restored session has appropriate timing and resource allocation, thereby minimizing service disruption and maintaining reliability
3Measurement precision
If absolute start time is required for session restoration, then timing precision is improved, but adaptability decreases when absolute start time is not available
Solution Approach 1:
The system performs preliminary actions by adjusting session parameters (session duration, time to data transfer) before the actual session restoration occurs. These pre-adjusted parameters are included in the session start request message, allowing the restoration to proceed with appropriate timing even without an absolute start time, thus maintaining both precision and adaptability
Data Source
AI summary
The embodiments herein relate to a method in a second CN node (205,407) for handling a failure in a communications network (200). The failure has caused communication between the second CN node (205, 407) and an old first CN node (203a) to become unavailable. The communication is associated with a session. When the failure has been detected, the second CN node transmits a session start request message to a new first CN node (203b, 405b, 410b). The session start request is a request to restore the session. The session start request message comprises a restoration flag indicating restoration of the session for a same service established before the failure and allowing a RAN node (201, 403) in the communications network (200) to accept the session start request message.