Sequence Number Table for Packet Retransmission Billing

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Solution Overview

Problem

In complex network environments, managing subscriber policies and accurately billing for data transmission is challenging due to issues with packet forwarding and retransmissions, leading to potential overcharging or undercharging, especially when quality of service policies are not properly enforced.

Innovation Solution

A method is implemented where a service gateway receives packets with sequence numbers, parses them, and generates a table entry for non-compliant packets. It compares subsequent packets' sequence numbers with the table to identify retransmissions, allowing for accurate forwarding and billing without redundant parsing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If packets are parsed and quality of service decisions are executed for each packet, then quality of service policy compliance is ensured, but processing time and system complexity increase due to redundant parsing of retransmitted packets

Engineering Contradiction:
Improvequality of service policy complianceVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary parsing of packets and records sequence number ranges in a table before potential retransmission occurs. When retransmitted packets are detected by comparing sequence numbers against the table, the system avoids redundant parsing by identifying them through sequence number matching alone, thus resolving the contradiction between ensuring QoS compliance and reducing processing time

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates a copy of sequence number range information in a table during initial packet processing. This copied information is then used to quickly identify retransmitted packets without needing to re-parse them, maintaining QoS policy enforcement while significantly reducing processing time for retransmissions

Inventive Principle:
Principle #26Copying

2Measurement precision

If all packets including retransmissions are billed, then accurate billing is achieved, but overcharging occurs when retransmitted packets are parsed and counted multiple times

Engineering Contradiction:
Improvebilling accuracyVSAvoidovercharging
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The system implements a feedback mechanism where sequence number ranges of parsed packets are recorded in a table. Before billing or forwarding packets, the system checks whether their sequence numbers already exist in the table, providing feedback that prevents double-counting of retransmitted packets and ensures accurate billing without overcharging

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary recording of sequence number ranges in a table during initial packet processing. This preliminary action enables the system to identify retransmitted packets before billing decisions are made, ensuring that only unique packets are billed and preventing overcharging while maintaining billing accuracy

Inventive Principle:
Principle #10Preliminary action

3Productivity

If sequence number tracking and table lookups are implemented to identify retransmissions, then redundant parsing is avoided, but device complexity increases

Engineering Contradiction:
Improvepacket processing efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system segments the packet processing function into two parts: initial parsing and quality of service decision execution, and retransmission identification through sequence number table lookup. This segmentation allows the complex parsing logic to run only once per unique packet, while retransmissions are handled by the simpler table lookup mechanism, improving productivity with controlled complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system extracts the sequence number identification function from the full packet processing pipeline. By separating the retransmission detection task (sequence number comparison) from the full packet parsing and QoS decision process, the system reduces overall complexity while maintaining high processing efficiency for identifying and handling retransmitted packets

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2505005B1System and method for providing a sequence numbering mechanism in a network environment
Publication Date: 2018.12.05 CISCO TECHNOLOGY INC
  • EP2505005B1 patent drawingFigure 1
  • EP2505005B1 patent drawingFigure 2
  • EP2505005B1 patent drawingFigure 3A~3C

AI summary

A method is provided in one example and includes receiving a plurality of packets associated with a flow; parsing the plurality of packets associated with the flow; executing a first quality of service decision such that a first set of packets within the plurality of packets are not forwarded to their intended destination; receiving a second set of packets, which reflects a retransmission of at least a portion of the first set of packets; executing a second quality of service decision such that the second set of packets is forwarded to their intended destination; and billing the second set of packets in response to forwarding the second set of packets. In more detailed embodiments, the method includes accessing a table in which entries are provided for particular sequence number ranges for the first set of packets.