GTP-U Cache for Protocol Error Recovery

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Solution Overview

Problem

In tunneling protocols like GTP-u, disruptions in the maintenance protocol can lead to inefficient removal of user plane data tunnel endpoints due to the lack of direct mapping between Tunnel Endpoint Identifiers (TEIDs) and User Entity database entries, resulting in time-consuming linear searches and potential corruption of search structures like hash tables.

Innovation Solution

Implementing a cache of outgoing packet identifiers to quickly recover from protocol errors by storing and matching TEIDs and node addresses, allowing for efficient identification and removal of user entities when errors occur.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If linear search is used to find user entity in User Entity database when protocol error occurs, then the search can be performed without additional data structures, but the search time becomes excessively long and system efficiency deteriorates

Engineering Contradiction:
Improvesearch timeVSAvoiddata structure complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-establishing a mapping cache that stores the correspondence between TEIDs and user entity identifiers before protocol errors occur. This cache is built during normal operation, so when an error happens, the system can immediately lookup the mapping without performing time-consuming linear searches through the User Entity database.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a mapping cache as an intermediary data structure between the TEID and the User Entity database. This intermediary layer provides direct access paths, eliminating the need for linear searches while maintaining data integrity. The cache acts as a mediator that translates TEID lookup requests into efficient user entity identifications.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If hash table is used to improve search efficiency, then search time is reduced, but the hash table may become corrupted over time leading to system reliability issues

Engineering Contradiction:
Improvesearch efficiencyVSAvoiddata structure integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent employs a simple mapping cache with straightforward insertion and lookup operations that is easier to maintain and less prone to corruption than complex hash tables. The cache uses basic data structures that are more resilient to degradation over time, sacrificing some advanced optimization for greater long-term reliability and easier maintenance.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Quantity of substance

If exhaustive search is performed in User Entity database to handle protocol errors, then no additional memory structures are needed, but memory waste increases and search performance deteriorates

Engineering Contradiction:
Improvememory usageVSAvoiderror handling efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The mapping cache is pre-populated during normal tunnel operation with the correspondence between TEIDs and user entity identifiers. This preliminary action ensures that when protocol errors occur, the system has ready-access information without needing to perform exhaustive searches, thereby improving error handling efficiency while using minimal additional memory.

Inventive Principle:
Principle #10Preliminary action

4Ease of operation

If direct mapping between TEID and User Entity database entries is maintained, then error recovery is efficient, but the system complexity increases due to additional data structures

Engineering Contradiction:
Improveerror recovery easeVSAvoidmapping structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent introduces a mapping cache as an intermediary that simplifies error recovery by providing direct TEID-to-user-entity mappings. While this adds a data structure, the structure is deliberately kept simple and lightweight, making the system easier to operate during error conditions without introducing excessive complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2178270B1Methods and apparatuses for using a cache of outgoing packet identifiers to recover from a protocol error in GTP-u
Publication Date: 2011.05.25 NOKIA SOLUTIONS & NETWORKS OY
  • EP2178270B1 patent drawingFigure 1
  • EP2178270B1 patent drawingFigure 2
  • EP2178270B1 patent drawingFigure 3

AI summary

A process of using a cache of outgoing packet identifiers to recover from a protocol error includes assigning a receive identifier associated with a user entity to a traffic stream at a receive node. The receive identifier is sent to a transmit node. The transmit node is instructed to associate the receive identifier with a receive plurality of data packets of the traffic stream The transmit identifier associated with the user entity is assigned to the traffic stream at the transmit node. The transmit node identifier, the receive node identifier, and the address of the receive node are stored in a transmit cache at the transmit node for each of the receive plurality of data packets. The receive plurality of data packets is sent from the transmit node to the receive node. An error message is received at the transmit node from the receive node, indicating that the receive identifier was not recognized. The transmit cache is searched for the transmit node identifier using the receive node identifier and the address of the receive node. The user entity associated with the transmit node identifier is identified, and the user entity is removed.