Serving Gateway Traffic Offloading During Restart

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Solution Overview

Problem

Current radio telecommunications networks face disruptions and increased signaling loads during serving gateway (SGW) restarts, leading to service interruptions and network instability, as existing mechanisms lack effective traffic offloading mechanisms for planned SGW restarts, resulting in deleted MM and EPS bearer contexts and increased signaling across EPC nodes.

Innovation Solution

A serving gateway support node is configured to detect failures and initiate relocation of connections from a first SGW to a second SGW, and upon recovery, restore connections to the original SGW by communicating context information, including identification, IP address, tunneling identifier, and Quality of Service values, thereby minimizing service disruptions and signaling loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a serving gateway is restarted for maintenance or capacity management, then the gateway can be upgraded or capacity can be optimized, but service interruptions and signaling loads increase

Engineering Contradiction:
Improvegateway capacity managementVSAvoidservice continuity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary actions by detecting SGW restart before it occurs and proactively relocating user connections to alternative SGWs. This prevents service interruption by ensuring connections are already migrated before the original SGW goes offline for maintenance or capacity management.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The MME acts as an intermediary between the restarting SGW and the core network. It detects the restart condition, manages the connection relocation process, and coordinates with alternative SGWs to maintain service continuity during the transition.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If connections are relocated during SGW restart, then service continuity is maintained, but signaling loads across EPC nodes increase

Engineering Contradiction:
Improveservice continuityVSAvoidsignaling load
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system applies partial action by selectively relocating only the necessary user connections affected by the SGW restart, rather than relocating all connections in the network. This minimizes unnecessary signaling while maintaining service continuity for impacted users.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The MME implements feedback mechanisms by monitoring SGW status and dynamically adjusting connection relocation decisions. It receives feedback about connection states and SGW availability, optimizing the relocation process to minimize signaling overhead while ensuring service continuity.

Inventive Principle:
Principle #23Feedback

3Ease of manufacture

If MM and EPS bearer contexts are deleted during SGW restart, then the restart process is simplified, but service disruptions occur

Engineering Contradiction:
Improverestart process simplicityVSAvoidservice interruption time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The system extracts the connection management function from the restarting SGW by relocating connections to alternative SGWs before the restart. This allows the original SGW to perform a clean restart without carrying over stale context information, simplifying the restart process while maintaining service continuity through the alternative SGWs.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system discards the MM and EPS bearer contexts in the restarting SGW to enable a clean restart, while simultaneously recovering service continuity by maintaining active connections through alternative SGWs. The contexts are recovered after restart through coordinated re-establishment procedures.

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP2693806B1Method and gateway for traffic offloading
Publication Date: 2018.06.27 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2693806B1 patent drawingFigure 1~2
  • EP2693806B1 patent drawingFigure 3
  • EP2693806B1 patent drawingFigure 4

AI summary

The present invention relates to a method for controlling connections that pass through at least one serving gateway of a radio telecommunications network, the method comprising the steps of receiving at a serving gateway support node a first message from an operator requesting that at least some connections be offloaded from a first serving gateway, and responding to the first message by the serving gateway support node relocating at least some of the connections from the first serving gateway to a second serving gateway. Also, a serving gateway comprising circuitry is configured to receive a connection restoration message from a serving gateway support node after the serving gateway has restarted, and respond to the connection restoration message by restoring in memory of the serving gateway at least some connections, which existed before the serving gateway restarted, between user equipment nodes and a packet-based network that passed through the serving gateway.