Serial Interface Overhead Data Transfer via Idle Bandwidth

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Solution Overview

Problem

In packet switching architectures, the transition from parallel to serial interfaces for data transfer over backplane connections is challenging due to noise susceptibility and cost concerns, requiring higher clock rates for individual data paths, which complicates accommodating additional data without reducing throughput or increasing the number of data paths.

Innovation Solution

Transferring overhead data over control paths during time periods when excess bandwidth is available, without impeding payload transfer, using a serial interface with distinct payload and control paths, allowing for concurrent or independent transfer modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If serial interface is used for backplane connection to reduce cost and noise susceptibility, then reliability is improved, but individual data paths must be clocked at higher rates which increases device complexity

Engineering Contradiction:

Improvenoise immunityVSAvoidclock rate

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The data transfer is segmented into payload data and overhead data, with payload transferred at high speed during active periods and overhead data transferred during idle periods. This segmentation allows the serial interface to maintain high reliability through differential signaling while managing clock rate complexity through time-division multiplexing of different data types.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The interface dynamically switches between transferring payload data and overhead data based on bandwidth availability. The control paths dynamically utilize idle time periods to transfer overhead data without requiring additional clock rates or data paths, thereby maintaining reliability while adapting to varying data transfer needs.

Inventive Principle:

Principle #15Dynamics

2Productivity

If clock rate is increased to maintain throughput in serial interface, then productivity is maintained, but device complexity increases

Engineering Contradiction:

Improvedata throughputVSAvoidclock rate

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The serial interface maintains continuous useful action by utilizing idle time periods to transfer overhead data. This ensures that the high clock rate is fully productive, transferring either payload or overhead data continuously without waste, thereby maintaining throughput while justifying the complexity through maximum resource utilization.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The interface changes the parameter being transferred (from payload data to overhead data) based on bandwidth availability. During idle periods, the same high-speed data path transfers overhead data instead of payload, allowing the system to maintain high productivity through parameter switching rather than requiring additional lower-speed paths.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If number of data paths is reduced in serial interface, then device complexity is reduced, but ability to accommodate additional overhead data is limited

Engineering Contradiction:

Improvenumber of data pathsVSAvoidaccommodation of overhead data

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The control paths in the serial interface are designed with multi-functionality, serving both as control signal carriers and as data transfer paths for overhead data. This universality allows the reduced number of data paths to accommodate additional overhead data by utilizing the same physical paths for multiple purposes at different times, maintaining adaptability without increasing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control paths dynamically switch between transferring control data and overhead data based on bandwidth availability. This dynamic behavior allows the same physical paths to adapt to different data transfer needs, enabling the system to accommodate variable overhead data requirements without requiring additional dedicated paths for each function.

Inventive Principle:

Principle #15Dynamics

4Adaptability or versatility

If overhead data is transferred over control paths during idle periods, then adaptability is improved, but may impede payload transfer throughput

Engineering Contradiction:

Improveflexibility in data transferVSAvoidpayload throughput

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The transfer of overhead data is performed periodically during idle time periods when the control paths are not actively transferring control data. This periodic action ensures that payload transfer throughput is not impeded, as overhead data transfer occurs only during naturally occurring idle periods in the payload data stream, maintaining both adaptability and productivity.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS7889658B1Method of and system for transferring overhead data over a serial interface

Publication Date: 2011.02.15 EXTREME NETWORKS INC

AI summary

A method of and system for transferring overhead data from a sender to a receiver over a serial interface is provided. The overhead data is transferred over one or more data lines of the interface during one or more time periods in which excess bandwidth is available on the one or more data lines or while the transfer of the overhead data does not substantially impede the throughput of the payload transfer.