SDN Link Detection Using Session Negotiation and Heartbeats

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Solution Overview

Problem

In SDN network architectures, there is a lack of effective methods for detecting link connectivity between network elements, which affects network stability and compatibility, particularly in hybrid network architectures.

Innovation Solution

An SDN device transmits a session negotiation packet to a second network element to establish a link, followed by a heartbeat packet to continuously detect connectivity, using configuration information to set transmission intervals and times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If common BFD is used to detect connectivity between network elements, then connectivity detection is available, but it is not applicable in SDN network architecture where control plane and forwarding plane are separated

Engineering Contradiction:
Improvecompatibility of SDN networkVSAvoidlink connectivity detection capability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces an SDN controller as an intermediary component that bridges the gap between traditional connectivity detection methods and SDN architecture. The controller establishes a detection session with the network element, enabling connectivity detection functionality that would otherwise be unavailable in the separated control-plane/forwarding-plane SDN structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The connectivity detection function is segmented into separate components: the SDN controller handles session management and detection logic, while the network element focuses on forwarding operations. This segmentation allows each component to specialize in its respective function while maintaining overall system compatibility.

Inventive Principle:
Principle #1Segmentation

2Reliability

If SDN device transmits session negotiation packet and heartbeat packet to detect link connectivity, then connectivity detection is achieved in SDN architecture, but additional message traffic is generated

Engineering Contradiction:
Improvelink connectivity detection capabilityVSAvoidmessage traffic
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The heartbeat packet serves multiple functions: it acts as both a connectivity detection mechanism and a session keep-alive signal. By combining these functions into a single packet type, the patent reduces the need for separate message streams, thereby minimizing additional traffic while maintaining reliable connectivity detection.

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

3Stability of the object's composition

If connectivity detection is implemented in SDN network, then network stability is enhanced, but device complexity increases due to additional detection mechanisms

Engineering Contradiction:
Improvenetwork stabilityVSAvoiddetection mechanism complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The network element itself participates in the connectivity detection process by responding to session negotiation packets and heartbeat packets from the SDN controller. This self-service approach distributes the detection burden, reducing the complexity burden on any single device while enhancing overall network stability through distributed detection capability.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3223459B1Method and SDN device for detecting connectivity
Publication Date: 2025.09.24 HUAWEI TECH CO LTD
  • EP3223459B1 patent drawingFigure 1~2
  • EP3223459B1 patent drawingFigure 3~4
  • EP3223459B1 patent drawingFigure 5~6

AI summary

Embodiments of the present invention disclose a method and an apparatus for detecting connectivity. An SDN device transmits a session negotiation packet to a second network element, where the session negotiation packet is used to negotiate a link between a first network element and the second network element, and the first network element is located in an SDN network; the SDN device obtains a response message returned by the second network element, to determine that the link is negotiated successfully; and the SDN device transmits a heartbeat packet to the second network element, where the heartbeat packet is used to detect connectivity of the link. As can be learned, after determining that the link between the second network element and the first network element located in the SDN network is negotiated successfully, the SDN device transmits the heartbeat packet to the second network element, so as to effectively detect the connectivity of the link. In this case, in an SDN network architecture or a hybrid network architecture having an SDN network architecture, link connectivity between the first network element and the second network element in the SDN can also be effectively detected.