5G Session Management Path Update for Intermediate UPF Changes

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Solution Overview

Problem

In 5G systems, existing network procedures for handover, service request, or registration update processes fail to timely update user plane tunnel information when an intermediate UPF is inserted or deleted, leading to potential user plane tunnel establishment failures due to outdated core-network tunnel information.

Innovation Solution

A path update method where a session management network element obtains and associates target path information with a data packet processing policy, allowing for timely updates of user plane paths when an intermediate UPF is inserted or deleted, ensuring continuous data packet processing without changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the SMF network element sends the original core-network tunnel information of the PSA to the I-UPF network element when the I-UPF is inserted or deleted, then the data packet processing policy remains unchanged, but the user plane tunnel establishment fails due to outdated tunnel information

Engineering Contradiction:
Improvedata packet processing policy stabilityVSAvoiduser plane tunnel establishment reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies preliminary action by updating the core-network tunnel information of the PSA in advance before user plane tunnel establishment. When the I-UPF is inserted or deleted, the SMF network element proactively updates the tunnel information (N3 tunnel and N9 tunnel) to ensure that the tunnel establishment process uses current, valid routing information, thereby preventing tunnel establishment failures while maintaining stable data packet processing policies

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by establishing a feedback loop where the SMF network element monitors the status of the I-UPF and automatically triggers updates to the core-network tunnel information. When the I-UPF status changes (insertion or deletion), the system detects this change and feeds back to update the tunnel information, ensuring that the tunnel establishment always uses up-to-date routing information without manual intervention

Inventive Principle:
Principle #23Feedback

2Reliability

If the core-network tunnel information of the PSA is updated when the I-UPF is inserted or deleted, then the user plane path can be established correctly, but the existing protocol assumption that core-network tunnel information does not change is violated

Engineering Contradiction:
Improveuser plane tunnel establishment reliabilityVSAvoidprotocol complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the core-network tunnel information dynamic rather than static. Instead of treating the tunnel information as fixed (as assumed in existing protocols), the system dynamically updates the N3 tunnel and N9 tunnel information based on the actual status of the I-UPF. This dynamic approach allows the tunnel information to adapt to network changes (I-UPF insertion/deletion) while maintaining protocol compatibility through standardized update procedures

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3787345B1Method, device, and system for updating path
Publication Date: 2023.08.02 HUAWEI TECH CO LTD
  • EP3787345B1 patent drawingFigure 1~2
  • EP3787345B1 patent drawingFigure 3
  • EP3787345B1 patent drawingFigure 4

AI summary

Embodiments of this application provide a path update method, a device, and a system, so that when an intermediate user plane network element is inserted or an intermediate user plane network element is deleted, a corresponding user plane path can be updated in a timely manner on a premise that a data packet processing manner is not changed. The method includes: A network device obtains target path information. The target path information includes first path information and/or second path information that are/is corresponding to an anchor user plane network element and that are/is allocated to a terminal. The first path information is used to establish a first path between the anchor user plane network element and an access device, and the second path information is used to establish a second path between the anchor user plane network element and an intermediate user plane network element. The network device associates the target path information with a target data packet processing policy. The target data packet processing policy is used to process a data packet received from the first path and the second path.