Middle-of-Rack Breakout Module Layout for Shorter High-Speed Links
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Solution Overview
Problem
Current server rack configurations face challenges in supporting higher data rates due to the use of passive cable assemblies exceeding 2.5 meters, which require forward error correction, leading to increased energy consumption and insufficient bandwidth support for QSFP connections.
Innovation Solution
Implementing a middle of the rack (MOR) switch connected to compute nodes with shorter cables (1.5 meters or less) and an electrical to optical panel (EOP) to convert electrical signals to optical signals, reducing cable length and thermal load, and using next-gen connectors for improved thermal management and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If passive cable assemblies longer than 2.5 meters are used in current TOR switch configurations, then the existing rack structure can be maintained, but forward error correction is required which increases energy consumption and limits data rate support
Solution Approach 1:
The patent divides the single TOR switch configuration into multiple MOR switches distributed at different vertical positions within the rack. This segmentation allows each MOR switch to serve a localized group of compute nodes with shorter cable assemblies, eliminating the need for FEC while supporting higher data rates up to 112 Gbps per directional channel
Solution Approach 2:
The MOR switch acts as an intermediary device between the compute nodes and the spine network. By positioning MOR switches at middle rack locations and using shorter passive cable assemblies (1.5 meters or less), the system achieves high-speed communication without requiring active optical modules or FEC, thereby reducing energy consumption
2Adaptability or versatility
If QSFP connections are used with passive cable assemblies exceeding 2.5 meters, then existing infrastructure can be utilized, but the connections are insufficient to support higher speed passive cable links
Solution Approach 1:
The patent transitions from a horizontal cable routing approach (TOR switch at top of rack) to a vertical dimension approach by placing MOR switches at multiple vertical levels within the rack. This dimensional change enables shorter cable lengths while maintaining adaptability for high-speed connections up to 112 Gbps
3Temperature
If TOR switch configuration is used with long passive cables, then the current architecture can be maintained, but thermal management becomes difficult and energy consumption increases
Solution Approach 1:
By segmenting the network into multiple MOR switches positioned throughout the rack, the patent reduces cable lengths and minimizes thermal load concentration. Each MOR switch handles a localized segment, improving thermal management and reducing overall energy consumption compared to the centralized TOR switch approach
Solution Approach 2:
The patent extracts the optical conversion function from the MOR switch to separate EOP (electrical to optical panel) units. This separation removes the thermal burden of optical modules from the MOR switch, improving thermal management while maintaining high data rate support
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution allows for high data rates without FEC, reduces energy consumption, enhances thermal management, and improves communication paths between servers, supporting data rates up to 112 Gbps per directional channel.
Implementation Method 1
an electrical to optical panel (EOP) to convert electrical signals to optical signals
Data Source
AI summary
A server rack with a plurality of compute nodes is positioned in a facility that includes a spine and the server rack includes a middle of rack (MOR) switch located near the middle of the server rack, vertically speaking. The MOR switch includes a plurality of ports that are connected via passive cables to the compute nodes provided in the server rack. In an embodiment the passive cables are configured to function at 56 Gbps using non-return to zero (NRZ) encoding and each cable may be about or less than 1.5 meters long. An electrical to optical panel (EOP) can be positioned adjacent a top of the server rack and the EOP includes connections to the MOR switch and to the spine, thus the EOP helps connect the MOR switch to the spine. Connections between adjacent server racks can provide for additional compute bandwidth when needed.