Dynamic Pseudowire Placement for L2VPN Connectivity After Fiber Node Split

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Solution Overview

Problem

Cable networks experience service outages due to loss of connectivity between cable modems when one modem is moved to a different fiber node during a fiber node split, requiring complex configuration file updates that service providers often avoid, leading to performance issues.

Innovation Solution

Implementing a routing protocol to propagate information across Cable Modem Termination Systems (CMTSs) and dynamically adjust pseudowire placement to maintain Layer 2 Virtual Private Network (L2VPN) connectivity, allowing cable modems to retain connectivity without updating configuration files.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a fiber node split is performed to improve network performance and load distribution, then network performance is improved, but L2VPN connectivity between cable modems is lost

Engineering Contradiction:

Improvenetwork performanceVSAvoidL2VPN connectivity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic pseudowire establishment and teardown based on real-time fiber node split events. When a cable modem is moved to a different fiber node, the system dynamically establishes new pseudowires between the source and destination CMTSs, allowing the network to adapt its connectivity structure in response to changing conditions while maintaining L2VPN service continuity

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent introduces a network controller as an intermediary that coordinates pseudowire management between CMTSs during fiber node splits. The controller receives split event notifications, calculates appropriate pseudowire configurations, and distributes configuration information to relevant CMTSs, enabling coordinated connectivity maintenance across the distributed network architecture

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If configuration files are updated to maintain L2VPN connectivity after fiber node split, then connectivity is maintained, but operational complexity increases

Engineering Contradiction:

ImproveL2VPN connectivityVSAvoidconfiguration management

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent enables CMTSs to automatically generate and configure pseudowire settings based on received fiber node split event information. Rather than requiring manual configuration file updates by operators, the system self-configures the necessary pseudowire parameters (source/destination MAC addresses, VLAN tags, etc.) by processing split event data and establishing appropriate connectivity paths

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent establishes pseudowires in advance in response to fiber node split events, preparing connectivity paths before service disruption occurs. The system proactively configures pseudowire parameters and establishes forwarding paths when split events are detected, preventing connectivity loss rather than attempting to restore it after failure

Inventive Principle:

Principle #10Preliminary action

3Reliability

If manual configuration file updates are performed to maintain connectivity, then L2VPN service continuity is achieved, but service outages occur during the update process

Engineering Contradiction:

ImproveL2VPN service continuityVSAvoidservice outage duration

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent maintains continuous L2VPN service during fiber node splits by establishing pseudowires that bridge the gap between source and destination CMTSs. The pseudowire configuration ensures that data forwarding continues uninterrupted across the network topology change, eliminating service outages that would otherwise occur during manual reconfiguration

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent replaces manual mechanical configuration processes with automated electronic pseudowire establishment. Instead of operators physically updating configuration files on CMTS devices, the system uses electronic signaling and automated configuration protocols to dynamically set up pseudowire connections, dramatically reducing the time required to maintain connectivity during network changes

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8873549B2Managing L2VPN connectivity after a fiber node split

Publication Date: 2014.10.28 CISCO TECHNOLOGY INC

AI summary

In one example, a routing protocol is used to propagate or flood information over a network of Cable Modem Termination Systems (CMTSs) in response to a fiber node split that changes which of the CMTSs a cable modem is coupled thereto. The network processes the information and dynamically changes a pseudowire placement to maintain the Layer 2 Virtual Private Network (L2VPN) connectivity among cable modems of different CMTSs after the fiber node split.