My mistake. Early draft (with incorrect information) included in the article. Our network guys corrected me. Here's what it's being updated to read:

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Finally, while 10Gbps Ethernet can run across standard Cat5/6 cable, we elected to use SFP+ connectors. We chose this to have the flexibility between optical (fiber) and copper connections. Some network card and switch vendors lock down their equipment to only support proprietary SFP+s, which they charge a significant premium for. We spent significant time testing a combination of SFP+ vendors before finding FiberStore, a SFP+ manufacturer from which we could directly source SFP+s at a reasonable price that worked in the network gear we wanted to use.