OAM Session Synchronization Across Logical Network Devices

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Solution Overview

Problem

In packet networks, there is no conventional technique to configure a pair of Operations, Administration, and Maintenance (OAM) maintenance points to be identical, leading to challenges in retaining active OAM sessions across multiple devices operating as a single logical device, especially during switchover events.

Innovation Solution

A logical Network Interface Device (NID) is composed of multiple physical or virtual NIDs, where an active maintenance endpoint synchronizes OAM session data with a dormant maintenance endpoint, allowing seamless switchover and maintaining active OAM sessions by mirroring configurations and providing copies of OAM Protocol Data Units (PDUs) or relevant information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple physical NIDs are deployed in redundant manner to form a single logical NID, then reliability is improved, but OAM session continuity deteriorates during switchover events

Engineering Contradiction:

ImproveredundancyVSAvoidOAM session continuity

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The dormant maintenance endpoint performs preliminary synchronization with the active maintenance endpoint before switchover occurs. OAM session data including continuity check status, performance metrics, and configuration parameters are pre-loaded into the dormant endpoint's database, ensuring immediate session resumption upon activation without interruption to the peer NID.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The active maintenance endpoint continuously replicates OAM session data to the dormant maintenance endpoint. This includes copying Protocol Data Units (PDUs), performance measurement data, and configuration parameters, creating an identical standby copy that can immediately take over the OAM session when needed.

Inventive Principle:

Principle #26Copying

2Stability of the object's composition

If active maintenance endpoint continuously synchronizes with dormant maintenance endpoint, then OAM session data consistency is improved, but network bandwidth consumption increases

Engineering Contradiction:

ImproveOAM session data consistencyVSAvoidnetwork bandwidth consumption

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

Instead of continuous real-time synchronization, the system employs periodic data transfer at predetermined intervals. The active maintenance endpoint transmits OAM session data updates to the dormant endpoint at scheduled times, reducing unnecessary network traffic while maintaining data consistency. This periodic approach balances consistency requirements with bandwidth conservation.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS11310102B2Retaining active operations, administration, and maintenance (OAM) sessions across multiple devices operating as a single logical device

Publication Date: 2022.04.19 CIENA CORP

AI summary

A logical Network Interface Device (NID) includes a first NID connected to a peer NID; a second NID connected to the peer NID and communicatively coupled to the first NID, wherein the first NID and the second NID are each connected to a network element for redundant communication to the peer NID, and wherein the first NID actively operates an active maintenance endpoint in an Operations, Administration, and Maintenance (OAM) session with the peer NID, and wherein the active maintenance endpoint synchronizes OAM session data with a dormant maintenance endpoint at the second NID. The dormant maintenance endpoint becomes the active maintenance endpoint responsive to a protection switch, and the dormant maintenance endpoint has the OAM session data in a database based on synchronization with the first NID.