Distributed SONiC Fabric Chassis Control Plane

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Solution Overview

Problem

Networking devices, such as switches and routers, come pre-configured with proprietary operating systems and software, making customization, scalability, and flexibility difficult due to closed architectures and protocols.

Innovation Solution

The implementation of SONiC (Software for Open Networking in the Cloud) as an internal switch fabric in chassis-based network switches, enabling the use of standard Ethernet ports and OSI Layer 2/3 routing protocols for interconnectivity between ASICs, and providing network virtualization techniques like VXLAN and enhanced functions like BGP and RDMA, creating a disaggregated control plane that replaces proprietary protocols and interfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If proprietary operating systems and software are used in networking devices, then device functionality is ensured, but customization, scalability, and flexibility are reduced

Engineering Contradiction:
Improvecustomization and flexibilityVSAvoidclosed architecture complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the networking device into distinct functional modules: line cards with ASICs for data plane operations, a backplane with its own ASICs, and a control plane running SONiC software. This segmentation allows each component to be independently configured and managed, enabling customization while maintaining functionality. The control plane is separated from the data plane, allowing software updates and configuration changes without affecting hardware operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a universal control plane using SONiC (Software for Open Networking in the Cloud) that can manage diverse hardware components from different vendors. The standardized Ethernet ports and OSI Layer 2/3 routing protocols enable the system to perform multiple functions including switching, routing, and network virtualization. This multi-functionality approach replaces proprietary protocols with universal standards, enhancing flexibility without sacrificing device functionality.

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

2Adaptability or versatility

If proprietary protocols and interfaces are used for chassis interconnect, then interoperability within the proprietary system is ensured, but scalability and adaptability to standard networking protocols are limited

Engineering Contradiction:
Improveprotocol compatibilityVSAvoidASIC production cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent introduces an intermediary control plane layer that translates between standard networking protocols and the internal chassis interconnect protocols. The SONiC control plane acts as a mediator, implementing OSI Layer 2/3 routing protocols that can communicate with external networks using standard protocols while managing internal communications through the backplane. This intermediary layer enables protocol compatibility without requiring custom ASICs for every protocol variant, reducing manufacturing costs.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of designing ASICs to support multiple proprietary protocols, the patent inverts the approach by using standard Ethernet ports and routing protocols at the interface level, with protocol translation and management handled in the control plane software. This inversion allows the use of standardized, lower-cost ASICs while maintaining protocol flexibility through software-based protocol implementation and translation.

Inventive Principle:
Principle #13The other way round (Inversion)

3Productivity

If routing control is distributed across multiple ASICs in the data plane, then routing functionality is provided, but ASIC complexity and production costs increase

Engineering Contradiction:
Improverouting control capabilityVSAvoidASIC routing table complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts complex routing control functions from the ASIC data plane and relocates them to the SONiC control plane. The ASICs are reduced to performing simpler forwarding operations based on routing tables populated by the control plane. This extraction reduces ASIC complexity and production costs while maintaining routing control capability through the software-based SONiC control plane that handles routing protocol processing, table management, and forwarding decisions.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If conventional supervisory modules are used for chassis management, then management functions are provided, but control plane complexity and failure risk increase

Engineering Contradiction:
Improvecontrol plane resilienceVSAvoidsupervisory module complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a self-service control plane where the SONiC software running on the backplane ASICs autonomously manages chassis interconnect operations. The control plane handles its own configuration, monitoring, and fault management without requiring external supervisory modules. This self-service approach reduces control plane complexity by eliminating redundant management layers while improving reliability through distributed control that can continue operating even if individual components fail.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3977689B1Distributed sonic fabric chassis
Publication Date: 2023.11.08 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3977689B1 patent drawingFigure 1
  • EP3977689B1 patent drawingFigure 2
  • EP3977689B1 patent drawingFigure 3

AI summary

SONiC (Software for Open Networking in the Cloud) is instantiated in a chassis-based (250) networking switch device (110) to enable control plane functionality for the line cards (235) and backplane (240). The SONiC platform may be configured with a routing table and BGP (border gateway protocol) to provide routing capabilities for the application-specific integrated circuits (ASICs) (210) operating on each respective line card (235). Ethernet ports (205) are utilized within the chassis (250) to enable the utilization of standardized networking protocols, such as protocols on the data link layer (layer 2) within the OSI (Open Systems Interconnection) model. The implementation of SONiC and standardized networking techniques creates a simplified and more proficient routing system in the chassis framework.