Lawful Intercept Interface Segmentation for Bandwidth Reduction

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Solution Overview

Problem

Lawful Intercept systems face bandwidth bottlenecks due to the overhead of TCP protocol in delivering communication content to Law Enforcement Agencies, which hampers network performance and increases operational costs.

Innovation Solution

Introduction of a new HI4 interface using UDP protocol for payload transmission, combined with a synchronization mechanism to retransmit lost packets, allowing for low bandwidth usage while maintaining data integrity through buffering and on-demand synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If TCP protocol is used for delivering communication content to Law Enforcement Agencies, then data integrity is ensured, but bandwidth usage increases and network performance deteriorates

Engineering Contradiction:
Improvedata integrityVSAvoidbandwidth usage
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent segments the data delivery mechanism into two parts: UDP for initial payload transmission (reducing overhead) and TCP for selective retransmission of lost packets (ensuring integrity). This segmentation allows the system to benefit from both protocols' strengths while mitigating their individual weaknesses.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using TCP for complete data delivery (excessive action with high overhead), the patent applies partial action by using UDP for the majority of transmissions and only invoking TCP retransmission mechanism when packet loss is detected. This reduces overall bandwidth consumption while maintaining necessary reliability.

Inventive Principle:
Principle #16Partial or excessive action

2Reliability

If TCP protocol is used for delivering communication content, then data integrity is maintained, but network capacity is reduced due to overhead

Engineering Contradiction:
Improvedata integrityVSAvoidnetwork capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent divides the delivery mechanism into UDP-based payload delivery (high productivity, lower reliability) and TCP-based retransmission (lower productivity, high reliability). This segmentation enables the system to achieve high overall network capacity while maintaining data integrity through selective use of TCP retransmission.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the reliability parameter dynamically by switching between UDP and TCP protocols based on packet loss detection. This parameter change allows the system to optimize network capacity by using the more efficient UDP protocol whenever possible, while maintaining data integrity through TCP retransmission when needed.

Inventive Principle:
Principle #35Parameter changes

3Loss of information

If all IP streams are intercepted and delivered as whole session data flow, then complete communication content is captured, but bandwidth consumption increases

Engineering Contradiction:
Improvecommunication content completenessVSAvoidbandwidth consumption
Core Design Contradiction:
Loss of informationVSLoss of energy

Solution Approach 1:

The patent extracts and delivers only the essential communication content using UDP, separating the bulk payload delivery from the reliability assurance function. This extraction allows complete communication content to be captured and delivered with reduced bandwidth consumption by eliminating TCP overhead from the primary delivery path.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3172881B1Lawful intercept systems and methods in li systems
Publication Date: 2020.09.02 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3172881B1 patent drawingFigure 1
  • EP3172881B1 patent drawingFigure 2
  • EP3172881B1 patent drawingFigure 3

AI summary

The present invention relates to a Lawful Intercept, LI, system and a method (S100) in a LI system comprising at least one Intercept Access Point, IAP, for intercepting communication traffic using User Datagram Protocol, UDP, and Transmission Control Protocol, TCP, packets in one or more communications networks. The IAP delivers said communication traffic as Communication Content, CC,to a Law Enforcement Agency, LEA, via a mediation functionality controlled by an administration functionality. The method comprises: - receiving (S110) CC as UDP and TCP; - storing (S120) UDP and TCP CC in a buffer arrangement; - forwarding (S130) TCP CC or UDP CC via a first CC handover interface HI3 or via a second CC handover interface HI4 separated from the first CC handover interface HI3 to the LEA. It is further provided a synchronization mechanism in order to retransmit all IP packets lost over the new interface HI4 and a buffer capacity process.