iWARP RDMA Read V2 Protocol Extensions

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Solution Overview

Problem

Current iWARP RDMA implementations have application-visible differences in RDMA Read operations compared to other RDMA technologies, such as InfiniBand, due to different semantics, leading to fragmentation and inefficiencies, particularly in supporting multiple local data buffers and remote access rights management.

Innovation Solution

Introduction of new RDMA Read V2 Request and Read V2 Response messages with extended opcodes and untagged DDP headers, allowing multiple local data buffers to be included in RDMA Read operations without requiring remote access rights, and simplifying rights management by removing the need for extra operations to grant and revoke access rights.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If iWARP uses original RDMA Read semantics, then implementation is simpler, but application transparency and consistency with other RDMA technologies is poor

Engineering Contradiction:

Improveapplication transparencyVSAvoidRDMA Read operation complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements extended RDMA Read operations that allow multiple local data buffers to be specified in a single Read request, making iWARP compatible with other RDMA technologies like InfiniBand. This multi-functionality enables the same application to run on different RDMA implementations without modification, achieving universality across RDMA platforms

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If iWARP supports multiple local data buffers in RDMA Read, then data transfer flexibility improves, but remote access rights management complexity increases

Engineering Contradiction:

Improvedata buffer flexibilityVSAvoidaccess rights management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the sink buffer location information from the RDMA Read request message itself, allowing multiple local data buffers to be specified without exposing their locations to remote peers. This separation enables flexible multi-buffer support while maintaining security and simplifying rights management, as the remote side only needs to send data without knowing where it should go

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If iWARP exposes sink buffer locations to remote peers, then RDMA Read operation is simpler, but security and data protection are compromised

Engineering Contradiction:

ImproveRDMA Read operation simplicityVSAvoidsecurity risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent uses the RDMA protocol infrastructure as an intermediary, where the RNIC hardware manages the mapping between sink buffers and source buffers. The sink buffer locations are kept private and managed locally, while the protocol handles the complex mapping transparently, maintaining both security and operational simplicity

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9558146B2IWARP RDMA read extensions

Publication Date: 2017.01.31 INTEL CORP

AI summary

Apparatus, method and system for supporting Remote Direct Memory Access (RDMA) Read V2 Request and Response messages using the Internet Wide Area RDMA Protocol (iWARP). iWARP logic in an RDMA Network Interface Controller (RNIC) is configured to generate a new RDMA Read V2 Request message and generate a new RDMA Read V2 Response message in response to a received RDMA Read V2 Request message, and send the messages to an RDMA remote peer using iWARP implemented over an Ethernet network. The iWARP logic is further configured to process RDMA Read V2 Response messages received from the RDMA remote peer, and to write data contained in the messages to appropriate locations using DMA transfers from buffers on the RNIC into system memory. In addition, the new semantics removes the need for extra operations to grant and revoke remote access rights.