Fibre Channel Zoning Engine Memory Reduction

Solution Overview

Problem

Implementing efficient zoning in large storage area networks with many hosts and storage devices is challenging due to the need to account for numerous source-destination combinations, which can lead to significant memory and power requirements in existing content addressable memory (CAM) solutions.

Innovation Solution

The solution employs a zoning engine with a destination Content Addressable Memory (CAM) and a membership table to store zoning decision vectors, allowing for efficient zoning decisions by separating source and destination information, and utilizing equivalency classes to reduce memory requirements, thereby implementing zoning rules without listing all possible source-destination combinations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all possible source-destination combinations are listed in CAM for zoning enforcement, then complete zoning coverage is achieved, but memory size and power consumption increase significantly

Engineering Contradiction:

Improvezoning enforcement completenessVSAvoidmemory size

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent segments the zoning decision process into two independent parts: destination-based CAM lookup and source-based vector selection. Instead of storing complete source-destination pairs, it separates the destination identification (stored in CAM) from the source-specific zoning decision (stored in vectors), thereby reducing memory requirements while maintaining complete zoning coverage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from a two-dimensional storage structure (source-destination pairs) to a three-dimensional structure by adding the dimension of zoning decision vectors. The CAM stores destinations, each destination has an associated vector, and each vector contains decisions for multiple sources. This dimensional transformation reduces the total storage requirements.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If all possible source-destination combinations are listed in CAM for zoning enforcement, then complete zoning coverage is achieved, but power consumption increases significantly

Engineering Contradiction:

Improvezoning enforcement completenessVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent segments the zoning decision process into two independent parts: destination-based CAM lookup and source-based vector selection. Instead of storing complete source-destination pairs, it separates the destination identification (stored in CAM) from the source-specific zoning decision (stored in vectors), thereby reducing memory requirements while maintaining complete zoning coverage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses zoning decision vectors that can be reused across multiple destinations for the same source. By copying and reusing the same vector for different destinations, the system avoids redundant storage and reduces the overall memory footprint, which in turn reduces power consumption.

Inventive Principle:

Principle #26Copying

3Reliability

If zoning decisions are made using traditional CAM storing all source-destination pairs, then complete zoning control is achieved, but device complexity increases

Engineering Contradiction:

Improvezoning control completenessVSAvoidzoning engine complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the zoning decision process into two independent parts: destination-based CAM lookup and source-based vector selection. Instead of storing complete source-destination pairs, it separates the destination identification (stored in CAM) from the source-specific zoning decision (stored in vectors), thereby reducing memory requirements while maintaining complete zoning coverage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces zoning decision vectors as an intermediary structure between the CAM and the final zoning decision. The vectors act as a mediator that translates destination-based CAM lookups into source-specific zoning decisions, simplifying the overall control logic and reducing device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8335231B2Hardware based zoning in fibre channel networks

Publication Date: 2012.12.18 CISCO TECHNOLOGY INC

AI summary

Provided are methods and apparatus that enforce zoning rules by separately employing source and destination information. In certain embodiments, information uniquely identifying network destinations is provided on a destination CAM. In these embodiments, each destination identified in the destination CAM has an associated zoning decision vector provided in a results memory. The vector provides specific zoning decisions (permit or deny transmission) for specific sources on the network. The specific zoning decision to be applied to a frame under consideration is selected from a zoning decision vector by using source information taken from the frame.