I believe I might have come across a way to link 4 nodes in an all-to-all mesh without an expensive switch, and am looking for advice on whether or not this will likely actually work.
Basically, the idea is for each Spark to have 1 normal copper DAC cable, and 1 transceiver feeding into a 2x2 optical shuffle cable in order to connect 3 devices with the 2 ports. It would go like this:
Lenovo PGX ConnectX-7 cable ($60): https://www.lenovo.com/us/en/p/accessories-and-software/cables-and-adapters/cables/4x91u42988
Naddod MPO 2x2 Shuffle Cable ($229): https://www.naddod.com/products/103276.html
(As far as I know, no copper shuffle cables exist, only optical)
QSFPTEK 100G Transceiver ($35.90): Cisco QSFP-100G-SR4-S 100GBASE-SR4 QSFP28 Transceiver Module - QSFPTEK
Given Sparks A, B, C, and D:
[Spark A Port 1] - [Spark B Port 1]: Lenovo Copper DAC Cable
[Spark C Port 1] - [Spark D Port 1]: Lenovo Copper DAC Cable
[Spark A Port 2 & Spark B Port 2] - [Spark C Port 2 & Spark D Port 2]: 4 Transceivers + Shuffle Cable
Total: ($60 x 2) + ($36 x 4) + ($229) = $493
Could anyone tell me if this would actually work or not? If anyone could fill in the details on the software side or the exact transceiver and cables types to ensure compatibility that would be great.