EVPN VPWS Tunnels for Redundant BNG Failover

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Solution Overview

Problem

Existing broadband network architectures lack efficient methods for providing redundant broadband network gateway services, leading to potential service disruptions during network failures.

Innovation Solution

The implementation of an Ethernet Virtual Private Network (EVPN) system that establishes layer 2 EVPN Virtual Private Wire Service (VPWS) tunnels over a layer 3 transport network, connecting subscriber access points to redundant broadband network gateway devices. This setup designates one gateway as primary and automatically switches to a redundant gateway in case of network failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If broadband network gateway functions are deployed to meet growing demand, then service coverage and bandwidth capacity are improved, but network vulnerability to single points of failure increases

Engineering Contradiction:

Improveservice coverage and bandwidth capacityVSAvoidnetwork resilience

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements asymmetric quality distribution by designating one BNG as primary and another as secondary with specialized roles. The primary BNG handles normal subscriber traffic while the secondary BNG maintains standby readiness, allowing each component to be optimized for its specific function and improving overall system reliability through differentiated local qualities.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent prepares redundancy in advance by establishing a secondary BNG that remains in standby mode before any failure occurs. This preemptive measure ensures that backup resources are already allocated and configured, enabling immediate failover without service disruption when the primary BNG fails, thus cushioning against potential failures.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If redundant broadband network gateway services are implemented, then network resilience is improved, but system complexity increases

Engineering Contradiction:

Improvenetwork resilienceVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent inverts the traditional active-standby relationship by having the secondary BNG actively monitor the primary BNG's health status and initiate failover when needed. This reversal of monitoring roles simplifies the control architecture, as the standby unit actively manages the transition rather than requiring complex coordination between multiple active units.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent creates a simplified copy of the BNG functionality in the secondary unit, which replicates essential gateway operations without needing to handle full subscriber traffic during normal conditions. This copying approach reduces complexity by maintaining only the critical path functionality in the backup, rather than duplicating the entire primary system.

Inventive Principle:

Principle #26Copying

3Reliability

If automatic failover mechanisms are deployed, then service continuity is improved, but control and management complexity increases

Engineering Contradiction:

Improveservice continuityVSAvoidcontrol and management

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent implements self-service automation where the secondary BNG autonomously monitors the primary BNG's operational status through heartbeat signals and automatically initiates failover when failure is detected, without requiring manual intervention. This self-service mechanism maintains service continuity while simplifying operations by eliminating the need for human operators to manage failover decisions.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent establishes a feedback loop where the secondary BNG continuously receives operational status information from the primary BNG and automatically adjusts its state accordingly. When the primary BNG becomes unavailable, the feedback mechanism triggers automatic failover, and when the primary recovers, the system can automatically revert or maintain the appropriate state, simplifying control through automated closed-loop management.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250175413A1Broadband access over ethernet virtual private network transport to redundant broadband network gateway service instances

Publication Date: 2025.05.29 AT&T INTELLECTUAL PROPERTY I L P

AI summary

Aspects of the subject disclosure may include, for example, creating network reachability on a layer 3 internet protocol underlay network between a subscriber access point and a first broadband network gateway (BNG) and between the subscriber access point and a second BNG, establishing Ethernet Virtual Private Network Virtual Private Wire Service (EVPN VPWS) Headend (HE) layer 2 termination between the subscriber access point and the first BNG and between the subscriber access point and the second BNG. Embodiments further include receiving a first advertisement of Ethernet Virtual Interface (EVI) reachability from the first BNG, receiving a second advertisement of EVI reachability from the second BNG, selecting the first BNG as a primary path for subscriber Virtual Local Area Network (VLAN) traffic for one or more subscriber devices, mapping a VLAN of the subscriber access point to a first EVPN VPWS tunnel for transport of the subscriber VLAN traffic to the first BNG, and communicating subscriber VLAN data over the first EVPN VPWS tunnel with the first BNG. Other embodiments are disclosed.