SDN Controller State Retention for RF Gateway Switchover

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Solution Overview

Problem

Shared bandwidth networks face challenges in maintaining high availability and efficiency, especially in handling rain fade conditions, where resource re-allocation is needed without significant unused resources and without impacting user experience, and re-establishing state after switchover is time-consuming and costly.

Innovation Solution

The system employs Software Defined Networking (SDN) and Network Functions Virtualization (NFV) controllers to dynamically move network resources, retain state during RF gateway switchover, and utilize a split link layer architecture between Satellite Network Core and Radio Frequency Gateway, enabling efficient source routing and redundancy management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If spectrum is utilized that is more subject to degradation in conditions such as rain fade to achieve higher bandwidth efficiencies, then bandwidth efficiency is improved, but network reliability deteriorates

Engineering Contradiction:
Improvebandwidth efficiencyVSAvoidnetwork availability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary actions by pre-establishing diverse RF paths and pre-configuring state distribution mechanisms before degradation occurs. When rain fade or other conditions degrade a primary path, the system can quickly switch to a pre-prepared diverse path without significant service interruption, thus maintaining network reliability while utilizing high-bandwidth spectrum.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary state distribution mechanism that decouples the state management from the degraded RF path. The state is distributed and maintained in a protected manner, allowing the system to switch RF paths without losing critical state information, thereby enabling reliable operation over degraded channels.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If redundancy/diversity resources are provisioned to maintain high availability, then network reliability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvenetwork availabilityVSAvoidredundancy resources
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes redundancy resources universal by designing diverse RF paths that can serve multiple purposes and multiple terminals. The same diverse path infrastructure supports various services and can be dynamically allocated, reducing the overall complexity compared to dedicated redundancy for each service or terminal.

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

Solution Approach 2:

The system implements a state distribution mechanism where state information is maintained in a recovered form across multiple locations. When switching between primary and diverse paths, the state can be recovered at the new path without requiring complete redundancy of all state resources at both locations simultaneously.

Inventive Principle:
Principle #34Discarding and recovering

3Reliability

If state is re-established after RF gateway switchover to handle temporary failures, then network reliability is improved, but loss of time increases

Engineering Contradiction:
Improveservice recoveryVSAvoidswitchover time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary state distribution before switchover occurs. Critical state information is pre-positioned or can be quickly retrieved from distributed sources, eliminating the need for time-consuming state re-establishment after gateway failure. This allows rapid switchover while maintaining service continuity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the system continuously monitors RF path conditions and maintains state synchronization across potential diverse paths. This feedback loop ensures that when switchover is needed, the state is already in a recoverable condition, minimizing the time loss during transition.

Inventive Principle:
Principle #23Feedback

4Reliability

If diverse RF paths are used to handle rain fade conditions, then network reliability is improved, but device complexity increases

Engineering Contradiction:
Improveresistance to rain fadeVSAvoidRF path management
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the complexity of diverse RF path management from the RF gateway itself and places it in the network core or control plane. The RF gateways simply execute switchovers based on directives, while the complex state distribution and path selection logic resides elsewhere, reducing the operational complexity at the RF path level.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3782337B1Maintaining and distributing state due to temporary failures in a shared bandwidth network
Publication Date: 2023.05.03 HUGHES NETWORK SYST
  • EP3782337B1 patent drawingFigure 1
  • EP3782337B1 patent drawingFigure 2
  • EP3782337B1 patent drawingFigure 3

AI summary

A shared bandwidth network system to communicate network traffic between terminals and an external network is disclosed. The system includes: a point of presence (POP) for the external network; Radio Frequency Gateways (RFGWs) wherein each RFGW of the RFGWs provides one or more Radio Frequency (RF) paths, and each of the RF paths links a respective RFGW of the RFGWs with one or more terminals of the terminals; an RF path state manager to manage a RF path state for each of the RF paths; a Satellite Network Core (SNC); a Software Defined Network (SDN) controller to maintain a topology based on the RF path states, wherein the topology includes the POP, the RFGWs and the SNC; and a network layer to route network traffic between the POP, the RFGWs and the SNC based on the topology. The SNC includes a bandwidth manager to allocate bandwidth, to provide flow control to the terminals, and to provide a key state including a bandwidth allocation for each of the terminals, a key state manager to maintain the key states, and a link layer control (LLC) to transport network traffic over each of the RF paths.