Fibre Channel Fabric In-Order-Delivery Management
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Solution Overview
Problem
Conventional storage area networks (SANs) face issues with in-order-delivery of frames, leading to unnecessary frame dropping when route changes occur, affecting both order-sensitive and non-order-sensitive devices within the same destination domain, and require burdensome configuration of in-order-delivery (IOD) parameters across the fabric.
Innovation Solution
Implementing zone-based, flow-based, and device ID-based classification techniques to manage in-order-delivery of data traffic, where affected zones, flows, or devices sensitive to frame order are identified and temporarily dropped, while non-sensitive ones continue to receive frames, using updated table entries and monitoring procedures to dynamically adjust IOD configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If in-order-delivery is enforced for all devices in a destination domain when a route change occurs, then frame delivery order is guaranteed for order-sensitive devices, but non-order-sensitive devices experience unnecessary frame dropping and disruptions
Solution Approach 1:
The patent segments the destination domain into order-sensitive and non-order-sensitive device groups. When a route change occurs, only frames destined for order-sensitive devices are dropped temporarily, while frames for non-order-sensitive devices continue to be delivered. This segmentation allows selective application of IOD penalties based on device characteristics rather than applying blanket restrictions to the entire destination domain.
Solution Approach 2:
The patent applies different quality treatments to different devices within the same destination domain. Order-sensitive devices receive the local quality of in-order-delivery guarantee through temporary frame dropping, while non-order-sensitive devices receive the local quality of continuous frame delivery without penalties. This local quality differentiation resolves the contradiction by tailoring the response to route changes based on individual device requirements.
2Reliability
If in-order-delivery parameters are configured manually across the fabric, then precise control over IOD behavior is achieved, but configuration complexity and administrative burden increase significantly
Solution Approach 1:
The patent enables the Fibre Channel fabric to automatically detect device characteristics and self-configure IOD parameters without manual intervention. The fabric monitors frame delivery patterns and device responses to automatically identify which devices are order-sensitive and which are not, then automatically applies appropriate IOD configurations. This self-service mechanism eliminates the need for manual configuration while maintaining precise control over IOD behavior.
Solution Approach 2:
The patent implements feedback mechanisms where the fabric monitors device responses to frame delivery and uses this information to automatically adjust IOD parameters. By observing whether devices require ordered delivery based on their response patterns and error rates, the system dynamically configures IOD behavior, replacing complex manual configuration with automated feedback-driven adaptation.
3Reliability
If all frames to a destination domain are dropped during route changes, then in-order-delivery is maintained, but network productivity and resource utilization decrease due to unnecessary frame loss
Solution Approach 1:
The patent extracts non-order-sensitive devices from the blanket IOD penalty application. Instead of dropping all frames to a destination domain affected by route changes, the system identifies and extracts frames destined for non-order-sensitive devices and allows them to continue delivery. This extraction of unnecessary frame drops reduces network resource waste while maintaining reliability for devices that actually require ordered delivery.
Data Source
AI summary
A technique is disclosed for managing in-order-delivery of data traffic in a storage area network which includes at least one host device adapted to communicate with at least one storage device via a fiber channel fabric. When a change in at least one route in the fiber channel fabric is detected, a first zone, flow and/or device in the network which is affected by the route change is identified, and frames associated with the first zone/flow/device are temporarily dropped for a temporary time period T. In one embodiment, the first zone/flow/device includes at least one device which is sensitive to the order in which data traffic is received. According to a specific implementation, a second zone/flow/device in the network which is affected by the route change, and which is not sensitive to the order in which data traffic is received may also be identified, and frames associated with the second zone/flow/device forwarded to their destination address during the temporary time period T.