The Switchberry is an OCP-TAP open source hardware project to build an open 1 Gbps managed Ethernet switch with PTP capabilities:
The PCB integrates a managed Gigabit Ethernet switch, exposing various interfaces and peripherals for a versatile and cost-effective 1G network switch with precision time protocol (PTP) capabilities.
This design combines powerful features of the Raspberry Pi CM4 with a managed switch to create an accessible, open, and versatile platform for learning, prototyping, and deploying time-synchronized networks.
The original design had 7 ports:
The latest version of the board is a 4-port variety, which is a bit more compact:
At its heart is a Microchip KSZ9567STXI 7-port Gigabit Ethernet switch with IEEE 1588, SGMII/RGMII/MII/RMII.
I have one on hand and will be testing it, now that I have the Time HAT up and running on a Pi 5: