[Cerowrt-devel] 2.5gbit for $59

[Matt Taggart]

On 6/2/22 10:11, David P. Reed wrote:
> There are small, low-TDP Intel systems for  up to ~$250 or so (including 
> case) that use current generation Celerons with 4 2.5 GigE ports, and 
> with the I/O bandwidth to easily support a full-on router at wirespeed 
> on those ports.
> 
> I'm thinking of upgrading my entry-router (which is based on Fedora 
> Server 36 now, not Cerowrt, just because that's my general go-to distro 
> on x86_64 and Aarch64) from an old Celeron system with two full speed 1 
> GigE ports to 2.5 GigE, in advance of my expectation that 2.5 GigE 
> DOCSIS 3.1 will become cheap enough soon at my home.
> 
> The problem with the low-end boards is that you need enough PCIe lanes 
> to move packets at 10 Gb/sec bidirectionally. The contained ARM chips 
> may be fast enough in principle, but the board and the PCIe are a 
> bottleneck.
> 
> AliExpress sells such boards and also barebones, but prices and specs vary.

The ones I see there seem to be using Celeron N5090 or N5105. Both have

"PCI Express 3.0 controller supporting 8 lanes (multiplexed); 4 lanes 
available externally"

They all seem to be using

"4x Intel i225-V"

Apparently earlier revs of that had problems but the "B3" stepping is 
supposed to be fixed.
Each uses pci-e 3.1 x1. So depending on how the board is laid out, they 
should have the bandwidth to actually do 2.5Gbit. All the usb ports, 
wifi, graphics, etc should all be using the internal lanes I think.

Here is a comparison of those celerons, the nanopi, and the pi4

https://www.cpubenchmark.net/compare/ROC-RK3568-PC-HDMI-(Android)-vs-BCM2711-vs-Intel-Celeron-N5105-vs-Intel-Celeron-N5095/4752vs4297vs4412vs4472

more details on the specific pages. The nanopi seems mostly better than 
the pi4, except some floating point and matrix.
The Celerons are much better CPUs, but are in a different power 
consumption and price class.

-- 
Matt Taggart
matt at lackof.org