Switch Pool Mechanism for Reducing Flow Switch Memory

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Solution Overview

Problem

In flow-based, split-architecture networks, the large forwarding table sizes in flow switches become a burden as the number of flows increases, leading to higher costs and network latency due to the need for frequent upgrades and potential disruptions when a flow switch fails.

Innovation Solution

The implementation of a centralized flow controller that determines flow paths and configures switch pools, where only one flow switch in each pool is programmed with flow entries, reducing the number of required entries and sharing forwarding tables among switches, thereby minimizing memory usage and latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If flow-based split architecture is implemented to decouple control and forwarding functions, then network adaptability and scalability are improved, but forwarding table sizes in flow switches increase significantly

Engineering Contradiction:

Improvenetwork adaptabilityVSAvoidforwarding table size

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent segments the forwarding table management by creating multiple flow switch pools (first pool, second pool, etc.) instead of having a single large forwarding table. Each pool handles specific flow entries, dividing the overall forwarding functionality into manageable segments that can be independently managed and scaled.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension to forwarding table management by organizing flow switches in hierarchical pools with different scopes (local flow switches, remote flow switches). This multi-dimensional organization allows efficient flow entry distribution across the network while maintaining manageable table sizes at each level.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If flow entries are distributed across multiple flow switches, then forwarding capacity is improved, but memory requirements and setup time increase

Engineering Contradiction:

Improveforwarding capacityVSAvoidmemory requirements

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent merges the forwarding capabilities of multiple flow switches into coordinated pools, where flow switches work together to provide collective forwarding capacity. By pooling resources and coordinating flow entry distribution, the system achieves high forwarding capacity while optimizing memory utilization across the pool members.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Flow switches within a pool are designed with multi-functionality, capable of handling different types of flow entries (local and remote flows) and serving multiple purposes. This universality allows the same hardware resources to be efficiently utilized for various forwarding tasks, reducing overall memory requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If centralized flow controller programs all flow switches with all flow entries, then forwarding accuracy is improved, but network latency and cost increase

Engineering Contradiction:

Improveforwarding accuracyVSAvoidnetwork latency

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements local quality by having flow switches program only the flow entries relevant to their specific location and function within the pool. Local flow switches handle local flow entries while remote flow switches handle remote flow entries, ensuring each switch has the precise information needed for its context without unnecessary overhead.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The centralized flow controller performs preliminary actions by pre-calculating and distributing flow entries to appropriate flow switches before traffic arrives. This proactive programming ensures that flow switches are ready to forward packets immediately without requiring real-time controller intervention, reducing latency.

Inventive Principle:

Principle #10Preliminary action

4Quantity of substance

If flow switch pools are used to reduce forwarding table sizes, then memory efficiency is improved, but device complexity increases

Engineering Contradiction:

Improvememory efficiencyVSAvoidpool configuration complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The centralized flow controller acts as an intermediary that simplifies pool configuration complexity. It automatically manages the distribution of flow entries to appropriate flow switches within pools, handling the complex coordination logic centrally while presenting a simplified interface to network operators and reducing the burden on individual flow switches.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8644149B2Mechanism for packet forwarding using switch pools in flow-based, split-architecture networks

Publication Date: 2014.02.04 VIVO MOBILE COMM CO LTD

AI summary

Method and apparatus for reducing forwarding table sizes in flow switches in a flow-based, split-architecture network is described. In an embodiment, a set of flow switches along a flow path is identified to form a switch pool. The forwarding table of only one of the flow switches in the switch pool is configured to have a flow entry that is associated with a particular flow. The flow entry includes a set of match fields for identifying packets belonging to that particular flow, and a set of actions to be performed on the packets belonging to that particular flow.