Raspberry Pi is a popular platform choice for playing mini routing, but the original version has only one network port, which is inconvenient in some uses, and requires an external USB network port. Now if you want to make a mini router with dual network ports, you can use Raspberry Pi
Compute Module 4, a company called Seeed Studio has given
it a set of mini router expansion boards.
Introduced in 2020, the Raspberry Pi Compute Module 4 takes the hardware of the Raspberry Pi 4 but removes the main interface and shrinks the PCB size to the size of a credit card. If other functions are needed, they can be realized through the expansion board. This set of mini routing expansion board is the way to play. Its PCB size is only 6 inches.
The dual Gigabit Ethernet NICs for Raspberry Pi Compute Module 4 provide two full-speed Gigabit RJ45 wired network ports, as well as two USB 2.0 ports, a microSD card slot, HDMI display output, and other complete interfaces, and it can expand the standard 40-pin GPIO interface of Raspberry Pi, and even a 0.91-inch monochrome OLED screen can be used to monitor network conditions, and it directly has OpenWRT firmware onboard, which is basically plug and play.
CM4 can become a mini router, gateway, NAS, and small server after matching with this expansion board. Seeed Studio said that the RTL8111E chip on the expansion board has better performance than the Raspberry Pi’s own network card, which can reduce the CPU load and provide a more stable network environment.