Aggregated Interface Connectivity Detection via Session Master Transition

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Solution Overview

Problem

Current network technologies, such as BFD, are inadequate for detecting connectivity failures in aggregated interfaces, leading to false interface flaps and inefficient resource utilization due to the need for multiple control plane sessions for each link, which can result in unnecessary resource wastage and incorrect operational states.

Innovation Solution

Implementing a single active forwarding plane connectivity detection session and passive sessions with synchronized parameters across multiple virtual network nodes, allowing for efficient detection of aggregated interface failures and seamless transition of mastership without interrupting the control plane, using techniques like micro BFD and dynamic anchoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple control plane sessions are established for each link in aggregated interfaces, then connectivity detection coverage is improved, but resource utilization deteriorates and false interface flaps increase

Engineering Contradiction:

Improveconnectivity detection coverageVSAvoidresource utilization

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent merges multiple control plane sessions into a single control plane session that monitors the entire aggregated interface. Instead of establishing separate BFD sessions for each physical link within the aggregation group, a single session is created that tracks the overall connectivity state of the aggregated interface, thereby reducing resource consumption while maintaining reliable detection.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single control plane session is designed to serve multiple functions simultaneously: it monitors connectivity across all links in the aggregated interface, detects failures, and triggers appropriate routing actions. This multi-functional approach eliminates the need for separate specialized sessions for each link, optimizing resource utilization while preserving comprehensive monitoring capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If multiple control plane sessions are established for each link in aggregated interfaces, then connectivity detection coverage is improved, but false interface flaps increase

Engineering Contradiction:

Improveconnectivity detection coverageVSAvoidfalse interface flaps

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

By combining multiple link-level monitoring sessions into a single aggregated interface-level session, the patent eliminates the phenomenon where individual link failures trigger spurious interface flap states. The single session evaluates the overall health of the aggregated interface based on the collective state of its constituent links, preventing false positives that occur when individual link failures are misinterpreted as complete interface failures.

Inventive Principle:

Principle #5Merging (Combining)

3Loss of energy

If a single active forwarding plane connectivity detection session is implemented, then resource usage is optimized, but detection capability may be reduced

Engineering Contradiction:

Improveresource usageVSAvoiddetection capability

Core Design Contradiction:

Loss of energyVSMeasurement precision

Solution Approach 1:

The single active forwarding plane connectivity detection session is designed with universal monitoring capability that covers all links within the aggregated interface. It employs mechanisms to track the state of individual links while maintaining a unified session, thereby preserving detection precision across the entire aggregation group without requiring multiple separate sessions.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces an intermediary mechanism that allows a single control plane session to indirectly monitor multiple physical links through the aggregated interface. This intermediary layer translates individual link states into aggregate interface state information, enabling the single session to maintain comprehensive detection capability while consuming minimal resources.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11283672B2Forwarding detection of an aggregated interface

Publication Date: 2022.03.22 JUNIPER NETWORKS INC

AI summary

The techniques describe detecting connectivity failure of an aggregated interface. To monitor connectivity of the aggregated interface, a packet processor of a plurality of packet processors is set as a session master responsible for managing an active forwarding plane connectivity detection session with a peer session master node. The other local packet processors of the virtual network node are selected as session standby nodes that each have a passive forwarding plane connectivity detection session running to the peer session master node. If a session master node goes down (i.e., by link or node failure), one of the local session standby nodes may detect the failure and is set as a new session master node by activating its passive session having the same session parameters.