DSL Backchannel Routing with Layer 2 Encapsulation

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Solution Overview

Problem

In vectored DSL systems, the routing of backchannel information with Layer 2 encapsulation becomes complex when Ethernet bonding is enabled, as existing standards like G.993.5 do not specify clear configurations for handling Layer 2 encapsulated backchannel packets relative to distributed bonding data fragments.

Innovation Solution

The solution involves selecting either EOC or Layer 2 encapsulation for backchannel communication, with options including pre-bonding multiplexing of backchannel and user data packets, preemption-based multiplexing, or dual bearer multiplexing, allowing for the separation and routing of backchannel data within the DSL system to a vectoring control entity for FEXT mitigation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Layer 2 encapsulation is used for backchannel communication in vectored DSL systems with bonding enabled, then communication flexibility and protocol compatibility are improved, but routing complexity and system configuration difficulty increase significantly

Engineering Contradiction:
Improvecommunication flexibilityVSAvoidrouting complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary routing mechanism that intercepts Layer 2 encapsulated backchannel packets at the access node, extracts their destination identifiers, and redirects them to the appropriate VCE instance. This intermediary routing layer decouples the complexity of Layer 2 encapsulation from the underlying routing infrastructure, allowing flexible communication while managing routing complexity through a standardized interception and redirection point.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the routing process into distinct functional stages: packet interception at the access node, destination identifier extraction, VCE instance determination, and packet redirection. By dividing the complex routing task into separable stages, each handled by specific system components, the patent manages overall routing complexity while maintaining Layer 2 encapsulation flexibility.

Inventive Principle:
Principle #1Segmentation

2Productivity

If multiple multiplexing methods are supported for backchannel and user data, then system adaptability and communication efficiency are improved, but configuration complexity and implementation difficulty increase

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidconfiguration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements dynamic multiplexing method selection where the system can adaptively choose among pre-bonding multiplexing, preemption-based multiplexing, or dual bearer multiplexing based on real-time system conditions, traffic patterns, and capability indications from VTU-O and VTU-R. This dynamic approach optimizes communication efficiency for different scenarios while the underlying framework manages configuration complexity through standardized capability negotiation during initialization.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent creates a universal multiplexing framework at the access node that can handle multiple multiplexing methods (pre-bonding, preemption-based, dual bearer) through a single standardized interface. This multi-functional design allows the system to support various multiplexing approaches without requiring separate dedicated processing paths for each method, thereby improving communication efficiency while containing configuration complexity through a unified handling mechanism.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of energy

If pre-bonding multiplexing is used to combine backchannel and user data packets, then communication overhead is reduced and efficiency is improved, but packet separation and routing difficulty increases at the receiving end

Engineering Contradiction:
Improvecommunication overheadVSAvoidpacket separation difficulty
Core Design Contradiction:
Loss of energyVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies preliminary action by performing packet separation and identification at the access node before packets reach the VCE, rather than requiring complex separation at the final destination. The access node extracts destination identifiers from multiplexed packets and pre-routes them to appropriate VCE instances, reducing the burden on downstream components and making the separation process more manageable through early intervention in the packet flow.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2719139B1Method and apparatus for DSL backchannel communication
Publication Date: 2016.08.10 IKANOS COMMUNICATIONS INC
  • EP2719139B1 patent drawingFigure 1
  • EP2719139B1 patent drawingFigure 2
  • EP2719139B1 patent drawingFigure 3

AI summary

DSL backchannel data and/or information is transported upstream in a vectored, bonded line DSL system. Backchannel data (e.g., error samples or the like from downstream-end DSL equipment) is encapsulated/packetized using Layer 2 encapsulation. Upstream user data is packetized into Ethernet packets or the like. The backchannel data and upstream user data are combined and the combined data transmitted to an upstream-end DSL apparatus, such as an access node. The combined data are separated in the upstream-end DSL apparatus so that the upstream user data can be processed further. The Layer 2 encapsulated backchannel data is decapsulated and then routed to a vectoring control entity or the like for use in operating the DSL system, for example in mitigating FEXT crosstalk in the DSL system's operation.