10G makes this a lot harder, both in terms of manufacturing and marketability.
I can understand that, it's just the point I think is interesting because it lets multiple devices run on a single connection at full 1G without blocking.
There aren't that many 10G switch chipsets you can buy from the open market
That's true but I did manage to find the
Broadcom one I mentioned in my initial post and it seems almost perfect for this.
AFAIK those that are on the market are on the higher end of the capability spectrum, so in addition to needing more careful circuit design/layout with BGA packages they also require more software development to bring the switch up (it's common for higher end switches to have built-in processors for management and complex switching logic, and you'd have to dig into the docs to see how much you need to do to get even basic packet switching).
The particular chip that I linked to is the Unmanaged version and,
while I can barely understand the doc, it seems like it shouldn't really need much software and is all built-in.
You'll also need to use external PHYs with many of them, which means routing MII signals which have more strict signal integrity requirements than the wire side MDI, and the whole board has to get bigger.
I know at least for this chip the 1G PHYs are internal and you wouldn't need one. The 10G I'm having more trouble with understanding the docs. They claim it's XFI which, if I understand correctly, means that it's signal is compatible with SFP cards directly. If that's true then the 10G PHY can be handled by the SFP+ card of the user's choice.
Then there just aren't that many applications that really demand 10G at the moment.
Fair point. Also while technically this would be an application demanding 10G since feeding multiple 1G devices without blocking needs it, it's also not super common to saturate multiple 1G connections at once especially in a home setting. I personally, just like the idea of being able to run a 10G connection to a room and then hook up multiple media devices and PCs and never worry about them interfering with each other.
If you're doing high-bitrate video editing or something else that requires bouncing a ton of data across the network then you probably just want 10G all the way from the PC to the storage, which requires a different kind of switch.
Oh, I know that. I already have my PC hooked up via 10G so that I can transfer data to/from my NAS faster.
If you're willing to drop the uplink to gigabit then it all gets a lot easier. You can buy single quantities of ~8 port gigabit unmanaged/lightly managed switch ASICs in QFP that can be configured by pin strapping or an external EEPROM, so just assemble the board and you're done. No external PHYs needed, so the only thing you're laying out is power and the copper MDI which is going to be much more forgiving than any MII interface (which you'd need to connect a switch to an external PHY). The MDI bandwidth is also only ~100MHz compared to ~500MHz with 10G. All of this can be done on a cheap-as-chips four layer board with a standard stackup from your favorite fabricator.
I'm certain of that too. I've seen
a cool project that fits a 5 port 1G switch into a tiny 45x45mm footprint. I could basically shove one of these in a gang box with no issues or at least use the same parts try redesigning the board.