FCoE Protocol Encapsulating Fibre Channel Frames in Ethernet
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Solution Overview
Problem
Current protocols for transporting Fibre Channel (FC) frames over Ethernet, such as FCIP and iFCP, are complex, expensive, and have low performance, and there is a need for a simpler, more cost-effective method that can leverage existing Ethernet infrastructure and legacy FC software drivers to enable efficient FC over Ethernet with 10 Gigabit data rates.
Innovation Solution
The Fibre Channel Over Ethernet (FCOE) protocol encapsulates FC frames within Ethernet frames, using Ethernet physical and link layers to transport FC frames, preserving higher FC layers and being transparent to them, allowing standard Ethernet switching hardware to be used, and utilizing Address Resolution Protocol (ARP) for address translation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If FCIP or iFCP protocols are used to transport FC frames over Ethernet, then FC frames can be transported over Ethernet infrastructure, but the protocols become complex, expensive to implement, and have low performance
Solution Approach 1:
The invention segments the FC protocol stack by separating the lower layers (physical and link layers) from the upper layers. The FC upper layers are preserved and remain unchanged, while the lower layers are replaced with Ethernet equivalents. This segmentation allows FC frames to be transported over Ethernet without requiring complex end-to-end protocols like FCIP or iFCP, thereby reducing protocol complexity while maintaining FC frame transport capability.
Solution Approach 2:
The invention introduces an intermediary encapsulation mechanism where FC frames are wrapped in Ethernet frames with appropriate Ethernet headers and trailers. This intermediary layer allows FC traffic to be transported over Ethernet infrastructure using standard Ethernet switching hardware, eliminating the need for complex FCIP or iFCP protocol implementations while preserving FC frame integrity.
2Reliability
If separate FC and Ethernet I/O controllers are used in blade servers, then FC and Ethernet traffic can be handled independently, but the system requires separate hardware components and increases complexity
Solution Approach 1:
The invention merges the separate FC and Ethernet I/O controllers into a single unified interface. By encapsulating FC frames in Ethernet frames, the system can use a single Ethernet I/O controller to handle both traditional Ethernet traffic and FC storage traffic, eliminating the need for separate FC and Ethernet HBA cards in blade servers. This reduces hardware complexity while maintaining independent traffic handling through Ethernet switching.
Solution Approach 2:
The invention makes the Ethernet I/O controller universal by enabling it to handle both standard Ethernet traffic and FC storage traffic through the FCOE encapsulation mechanism. This multi-functionality allows a single Ethernet adapter to replace dedicated FC HBA cards, reducing the number of hardware components required in blade servers while maintaining the ability to independently manage different traffic types through Ethernet switching infrastructure.
3Adaptability or versatility
If legacy FC software drivers are preserved, then compatibility with existing FC applications is maintained, but the protocol requires complex translation and adaptation layers
Solution Approach 1:
The invention creates a copy of the FC frame structure within the Ethernet frame payload. By preserving the exact FC frame format (including FC headers, data, and trailers) within the Ethernet encapsulation, the system maintains byte-for-byte compatibility with legacy FC software drivers. The FC upper layers see no difference in their data format, eliminating the need for complex translation layers while maintaining driver compatibility.
Solution Approach 2:
The invention performs preliminary encapsulation of FC frames in Ethernet frames at the source end before transmission. This preliminary action prepares the data in advance so that legacy FC software drivers can operate on the encapsulated frames without modification. The encapsulation is done beforehand, eliminating the need for complex real-time translation or adaptation layers during data processing, thereby simplifying the overall system architecture.
Data Source
AI summary
The use of Ethernet as an underlying transport for Fiber Channel (FC) frames is disclosed in the Fiber Channel Over Ethernet (FCOE) protocol. In FCOE, the FC physical layer and part of the FC-2 link layer are replaced with the Ethernet physical and link layers. Each FC frame is encapsulated within an Ethernet Frame. The payload of the FCOE frame contains type information from the FC Start Of Frame (SOF) indicator, the FC header, an optional FC payload, and type information from the FC End Of Frame (EOF) indicator. In one embodiment, an Ethernet network carrying FCOE replaces a standard FC network. In another embodiment, devices implementing FCOE may be implemented in a blade server. The entire backplane is Ethernet, over which both storage and networking traffic can be run. The Ethernet links are connected to an Ethernet switch, a FCOE/FC converter, and a FC switch.