Fibre Channel Fabric Partial Build Merge Process

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Solution Overview

Problem

The existing Fibre Channel fabric merge process is time-consuming, requiring approximately 15 seconds for building a new fabric, which limits network expansion and device linking due to the need for a full Principal Switch selection and Domain_ID assignment phase.

Innovation Solution

Implementing a partial build process where one fabric maintains its Principal Switch, allowing a limited 'partial build' for the other fabric, thereby skipping the conventional 10-second Principal Switch selection phase and reducing the build time to a few milliseconds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a full Principal Switch selection and Domain_ID assignment process is performed during fabric merge, then routing ambiguity is eliminated and network stability is ensured, but the build time increases to approximately 15 seconds

Engineering Contradiction:

Improverouting ambiguity eliminationVSAvoidfabric build time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies partial action by performing only the necessary Domain_ID assignment phase without executing the full Principal Switch selection process. When merging fabrics, the system skips the 10-second Principal Switch selection phase and proceeds directly to Domain_ID assignment, which is sufficient to eliminate routing ambiguity. This partial approach reduces build time from 15 seconds to a few milliseconds while maintaining routing correctness.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent uses preliminary action by pre-establishing the Principal Switch role in one of the merging fabrics before the merge occurs. This pre-configured Principal Switch can immediately assign Domain_IDs to switches from the other fabric without needing to re-select a Principal Switch, thereby eliminating the time-consuming selection phase while ensuring routing ambiguity is resolved.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a full fabric build process is executed during network expansion, then all switches receive proper Domain_IDs and the fabric is stable, but the port bring-up time is significantly increased

Engineering Contradiction:

Improvefabric stabilityVSAvoidport bring-up speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs only the essential Domain_ID assignment phase rather than the complete fabric build process. Since one fabric already has a established Principal Switch, the system skips the Principal Switch selection and proceeds directly to Domain_ID assignment for the new switches, achieving fabric stability with much faster port bring-up time.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The existing Principal Switch in the established fabric serves itself and the merging fabric by immediately assigning Domain_IDs without needing to re-establish its Principal Switch role. This self-service capability allows the Principal Switch to quickly integrate new switches from the merging fabric, accelerating port bring-up while maintaining stability.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS7876707B2Partial build of a fibre channel fabric

Publication Date: 2011.01.25 CISCO TECHNOLOGY INC

AI summary

In one embodiment, a technique for performing partial build fabric operations when merging two or more Fibre Channel fabrics is provided. By maintaining a Principal Switch already assigned for one of two merging fabrics, a limited “partial build” may be performed for the other merging fabric. As a result, the time required for a Principal Switch selection phase may be greatly reduced.