ports - at least 20 ports, ideally 24 ports (HDL support)
Submitted comment: The chosen Zynq Ultrascale+ device (XCZU17EG-1FFVC1760E) has 48 GTH/GTY transceivers. It is a waste to stick to 18 ports. Many commercial switches have 24 ports minimum. If it isn't taken into account now it will never be upgraded later (See INT-2 table 1 of [1]). There is front panel space for 3 blocks of 2x4 SFPs = 24 ports when SMAs are stacked using SMA feed-through cable assemblies that connect to connect to SMAs on the main PCB (see for example [5], other example use in MultiSFP Crate [6] or HPSEC [7]). KM3NeT would love to have at least 20 ports!