SDN Controller Switch Link Failure Detection BFD

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Solution Overview

Problem

In Software-defined Networking (SDN), network failures lead to significant propagation delays and processing overhead due to distant controller-switch distances and complex routing calculations, resulting in prolonged fail-over times and increased network processing costs.

Innovation Solution

Implementing the Bidirectional Forwarding Detection (BFD) protocol to enable switches to independently detect link failures and update flow tables quickly, reducing the reliance on the controller for routing calculations and message propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the controller physically manages a large number of switches with wide coverage, then the network management capability is improved, but the propagation delay increases due to increased physical distance between controller and switches

Engineering Contradiction:

Improvenetwork management capabilityVSAvoidpropagation delay

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The network is segmented into multiple control domains, each with its own controller. This allows local controllers to manage local switches with minimal propagation delay, while the overall network maintains wide coverage through hierarchical coordination between controllers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system transitions from a single centralized controller to a multi-dimensional hierarchical controller architecture. This adds spatial distribution as a new dimension, allowing the network to scale coverage without proportionally increasing propagation delay by introducing intermediate controller layers.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the controller performs routing calculations and flow entry generation for each network event, then the routing optimization is improved, but the processing delay increases due to complex internal algorithm calculations

Engineering Contradiction:

Improverouting optimizationVSAvoidprocessing delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The controller pre-calculates and stores optimal routing paths and flow entries for anticipated network conditions. When network events occur, the system retrieves and applies pre-computed routing information, avoiding the need for real-time complex calculations and reducing processing delay.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Switches are empowered to perform local routing decisions based on pre-configured flow tables and local event detection. This self-service capability at the switch level reduces the processing burden on the controller, allowing the controller to focus on global optimization while switches handle local real-time decisions.

Inventive Principle:

Principle #25Self-service

3Reliability

If switches frequently exchange event messages with the controller during network failure, then the failure detection capability is improved, but the network overhead increases due to repeated message propagation

Engineering Contradiction:

Improvefailure detection capabilityVSAvoidnetwork overhead

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The system extracts and implements a lightweight dedicated failure detection mechanism (BFD protocol) separate from general control plane messaging. This specialized detection channel uses minimal overhead packets specifically optimized for failure detection, reducing the energy consumption and overhead associated with frequent general event message exchanges.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The BFD protocol creates simplified copies of failure detection functionality that operate independently from the main control plane. These lightweight detection sessions use minimal resource copies (small packets, simple state machines) to achieve reliable failure detection without the overhead of full event message propagation.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS10205681B2Method for operating controller and switch for relieving network failure from SDN, and controller and switch therefor

Publication Date: 2019.02.12 SAMSUNG ELECTRONICS CO LTD

AI summary

The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4th-Generation (4G) communication system such as Long Term Evolution (LTE). A controller and a switch for network failure relieving from a software-defined networking (SDN) is provided. A method for operating the controller includes: transmitting, to the switch, path information for at least one packet and a session establishment message to establish a session for detecting a link failure of the at least one packet based on information regarding a capability of detecting a link failure of the switch. The method also includes receiving, from the switch, a session status message regarding a status of the session. If the status of the session is identified as the link failure, updated path information for the at least one packet based on information of the session is transmitted to the switch.