Exactly this. With VLAN tagging you can plug that single 2.5Gb connection into a 48-port managed switch and effectively have up to 47 different NICs if that's what floats your boat. They'd all share the 2.5Gb but that's still more than a lot of small networks need.
In a shared 2.5Gb scenario as you describe, would fully pegged upload/download be 1.25Gb each? Could it do 2.5Gb in both directions simultaneously? Assuming no compute bottlenecks.
It's full duplex so it's 2.5Gb each way simultaneosly. Most NICs support half-duplex but I don't know of any good reason to use that. I used to have a BananaPi based router that could comfortably saturate it's gigiabit interface. I assume there's some kind of offloading going on.
Well the router I use today has 4 ports (and a built in modem for that matter, but I don’t use that).
I understand I can use a switch, but that means I’ll have to buy a switch in addition to this to replace my router.
Which is not a bad thing, it’s more unix if you will. Router is a router, switch is a switch.
You provide your own switch and you choose the features: port count, port speed, vlan, etc — or get a 10€ switch if you don’t care. When a port breaks you replace the switch alone.
Multifunction tools are generally a tradeoff where you buy immediate convenience and pay with more ewaste and more money in the long run.
I also wanted to chime in with the perennial point that while this device is a pure expression of the OpenWrt project, they also support hundreds of other devices including, amazingly, a number of large switches, so if you wanted to ditch the separate route appliance altogether you could get all the features with only switch hardware.
I have 3 but they’re not close to the router. (What I’m saying is: I’m likely target audience, but I don’t have an additional switch nearby, since so far any router I had also had a built in switch.)
But yeah, I get it. Modularity makes sense for repairability.