OpenFlow Switch Processing Units for Pseudowire and OAM Support

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Solution Overview

Problem

Traditional network architectures with tightly coupled forwarding and control planes complicate network management and hinder the adoption of new protocols and technologies, as they do not efficiently support advanced network functionalities like pseudowires and Operations, Administration, and Maintenance (OAM) functions, leading to high delays in link failure discovery and network convergence.

Innovation Solution

An OpenFlow-based split-architecture network with enhanced switches that include processing units coupled to the OpenFlow pipeline, allowing for high-speed packet processing and support of functionalities not covered by the current OpenFlow specification, such as pseudowires and MPLS-TP OAM, by directing packets to designated processing units for enhanced handling and re-injection into the flow tables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional tightly coupled architecture is used, then control plane and forwarding plane are integrated in same device, but network management becomes overly complicated and new protocols cannot be adopted efficiently

Engineering Contradiction:

ImproveAbility to adopt new protocols and technologiesVSAvoidNetwork management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the traditional monolithic network device into separate forwarding elements (switches) and control elements (controllers). The forwarding plane resides in switches that perform packet forwarding based on flow tables, while the control plane resides in controllers that compute forwarding decisions. This segmentation allows independent evolution and adoption of new protocols in each plane without complicating the other, directly resolving the technical contradiction between adaptability and management complexity.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If OpenFlow pipeline is used for packet processing, then standardization is improved, but functionalities like pseudowires and OAM are not supported

Engineering Contradiction:

ImproveSupport for advanced network functionalitiesVSAvoidLink failure discovery and network convergence

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces processing units as intermediary components between the OpenFlow pipeline and advanced network functionalities. These processing units act as mediators that can handle specialized functions like pseudowires and OAM while still communicating through the standardized OpenFlow interface. This allows the system to support advanced functionalities without breaking the standardized OpenFlow pipeline, resolving the contradiction between adaptability and reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If controllers compute and distribute forwarding decisions, then centralized control is achieved, but processing delays increase

Engineering Contradiction:

ImproveCentralized network controlVSAvoidPacket processing delay

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The patent implements flow tables in switches that pre-compute and store forwarding decisions before packets arrive. When packets need advanced processing, the switches can quickly identify and forward them to appropriate processing units using pre-established rules in the flow tables. This preliminary action at the switch level reduces the time packets spend waiting for controller intervention, resolving the contradiction between centralized control and processing delay.

Inventive Principle:

Principle #10Preliminary action

4Adaptability or versatility

If processing units are added to switches, then enhanced functionalities are supported, but switch complexity increases

Engineering Contradiction:

ImproveEnhanced network functionalitiesVSAvoidSwitch internal structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs processing units with universal interfaces that communicate through the existing OpenFlow pipeline and flow table structure. Rather than creating dedicated complex pathways for each function, the processing units use the universal OpenFlow messaging framework to interact with the controller and flow tables. This multi-functional approach allows enhanced capabilities while minimizing additional complexity by reusing existing infrastructure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8971338B2Expanding network functionalities for openflow based split-architecture networks

Publication Date: 2015.03.03 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method enables a switch in a split-architecture network to provide high speed packet processing and enhanced network functionalities that are not supported by the OpenFlow. The switch receives a packet from a network through an input port of the switch, and matches header fields in the packet against table entries in flow tables to identify an action to be taken. The flow tables are part of an OpenFlow pipeline. The identified action is to direct the packet to a designated processing unit in the switch. The OpenFlow pipeline forwards the packet to the designated processing unit via a communication channel in the switch. The designated processing unit processes the packet with the enhanced network functionalities, and injects the packet back to one of the flow tables before transmission of the packet to the network through an egress port of the switch.