Tunnel Identification in 5G PDU Sessions
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Solution Overview
Problem
Current 3GPP specifications lack a method to identify two tunnels set up for a protocol data unit (PDU) session when split in a user plane function, leading to ambiguity in modifying tunnel information, especially when one tunnel is removed or additional tunnels are established.
Innovation Solution
Assigning explicit tags or using existing parameters like TNL addresses and QoS flow indicators to uniquely identify tunnels, or establishing rules to determine which tunnel is the first or additional tunnel, allowing for clear identification and modification of tunnel information during PDU session management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two tunnels are set up for a PDU session when split in UPF, then the system supports dual connectivity and load distribution, but it becomes impossible to identify which tunnel information will be modified
Solution Approach 1:
The patent divides the tunnel identification problem by introducing a tunnel indicator field that segments the identification process. Each tunnel is uniquely identified by combining the PDU session ID with a specific tunnel indicator value (0 for first tunnel, 1 for second tunnel), allowing clear distinction between multiple tunnels within the same PDU session.
Solution Approach 2:
The patent introduces an intermediary element - the tunnel indicator field - that mediates between the PDU session level and the individual tunnel level. This intermediary allows the system to track and modify specific tunnels without confusion, acting as a bridge between the aggregated PDU session view and the individual tunnel identities.
2Adaptability or versatility
If additional tunnels are dynamically added or removed, then the system maintains flexibility in resource allocation, but the identification of first and additional tunnels becomes ambiguous
Solution Approach 1:
The patent applies preliminary action by pre-assigning tunnel indicator values when tunnels are created. The first tunnel is assigned indicator 0 and the second tunnel is assigned indicator 1 during the tunnel setup phase, establishing clear identification before any dynamic additions or removals occur. This prevents identification ambiguity during subsequent dynamic changes.
Solution Approach 2:
The patent uses parameter changes by introducing the tunnel indicator as a new parameter that changes based on tunnel creation order. When a new tunnel is added, the system updates the tunnel indicator parameters to maintain proper sequencing, allowing dynamic tunnel management while preserving clear identification through parameter updates rather than structural changes.
3Ease of operation
If tunnel modification is initiated by NG-RAN or 5GC, then the system enables flexible tunnel reconfiguration, but there is no way to determine which specific tunnel will be modified
Solution Approach 1:
The patent implements feedback by including the tunnel indicator in the modification request messages exchanged between NG-RAN and 5GC. When either entity initiates a tunnel modification, the tunnel indicator value is fed back in the message to confirm which specific tunnel is being modified, ensuring that the target tunnel is unambiguously identified throughout the reconfiguration process.
Solution Approach 2:
The patent adds another dimension to the tunnel identification by introducing the tunnel indicator as an additional identifying parameter alongside the PDU session ID. This dimensional addition transforms the identification from a single-parameter system to a two-parameter system, enabling precise targeting of specific tunnels during reconfiguration operations.
Data Source
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AI summary
A method, system and apparatus for identification of two tunnels that have been set up in one protocol data unit (PDU) session are disclosed. According to one aspect, a method implemented in a radio network node includes transmitting to a core network node a first message that includes a Transport Network Layer, TNL, address for a downlink tunnel. The method further includes receiving from the core network node a reply message that includes an uplink, UL, transport layer address corresponding to the TNL address for the downlink tunnel