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by benj111 40 days ago
As someone not involved in this space I assumed there was specialist hardware. My pi Pico can do fancy things with DMA etc, without the CPU at all.

So why isn't there this kind of stuff in routers?

2 comments

"So why isn't there this kind of stuff in routers?"

Specialized hardware is in routers. Typically, for this class of router, what you're buying is a highly specialized proprietary chipset and a stack of proprietary driver software that runs on a couple ARM cores. Most of the actual network activity is offloaded (switching, packet filter, cryptography, etc.,) and the software control plane just manages the proprietary hardware. The specialized hardware is why the thing can handle traffic at full rate in a compact box with little to no active cooling and a ~10W SMPS.

That doesn't exist in this router: it can't because no one has yet integrated a best-of-class hardware data plane with a RISC-V CPU+drivers and made it available to third parties for developing such devices. So nearly everything must be done by the CPU, and the CPU isn't all that fast.

If you'd like to learn about all this, have a look at Tomaž Zaman's YouTube channel and his development of an "open" router.

There is, and it is. Just not in this specific SoC, originally intended for general-purpose computing.
So why would CPU speed be the bottleneck then?
Because this board doesn't have specialized routing hardware and will have to do everything in CPU.