Rpi4b ethernet connectivity questions

Evening all, just want to ask a simple question to you folks.

Running a RPi4 on snapshot builds of my own, using a UE300 usb adapter for the WAN and the onboard ethernet adapter for my LAN.

Currently, I have the LAN going into 8 port switch, from which wired devices are connected, but also one connection is to my wireless mesh master AP.

What I'm wondering is, would it be an advantage performance wise to use another UE300 adaptor directly into the RPi4, and run the wireless AP direct to it, and use the network switch purely for wired connectivity?

So say LAN1 to wired switch devices, and LAN2 to the wireless AP.. if I did this, would wireless devices on LAN2 be able to access things like my wired NAS on LAN1 or would I need complicated firewall rules.

Also this ones not a Openwrt related question, but I've run out of ethernet ports on my switch, so was going to get a new 16 port switch, but they are all so big and not really "livingroom" compatible, so could I add another far smaller 8 port item connected into the first one, I know I'll lose two ports linking them together but it's not a problem if it will work ok.

Probably not a performance benefit, but you'd free up a switch port by doing so.

You could add both interfaces to the same firewall zone, for convenience.

Alternately, if you eventually decided you wanted to introduce some segregation you could put them into separate zones and set up rules to control the traffic accordingly.

Netgear does a range of small 16-port switches. I have a Netgear GS-116 unmanaged switch here, which is less than a foot wide. It's small enough to tuck behind most televisions/soundbars/etc. According to Netgear's website (I can't find my tape measure), it's 11.2" wide x 4" deep x 1" high.

Netgear's not the only vendor, either; there's plenty to choose from. A word of advice, though: check for passive cooling/fanless, if you're considering putting a switch into a living room; the noise of an actively-cooled device can sometimes be distracting. Some vendors don't explicitly state fanless, but do give an acoustic rating in decibels. If the relevant value is 0 decibels, then it's fanless.

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That probably depends on your typical traffic... and the traffic engineering you might want to use.
If you want special filtering for WiFi (like e.g. extra IoT and/or guest SSIDs) attaching the AP via a dedicated ethernet dongle might make sense (it will spare you a few VLAN gymnastics and results in a simpler configuration but in all honesty, the required gymnastics are a one time cost, once it runs you probably do not need to touch it any more). Also if you had a 2Gbps lan link, a second dongle would allow a total sum internet usage higher than the 1 Gbps that the Pi's ethernet port allows (but you would need at least one 2.5 Gbps ethernet dongle that is actually supported/recognized by OpenWrt). So all in all you are probably fine with keeping the AP connected to the switch.

Regarding the question replace switch with bigger switch and daisy chain switches, it comes down to your typical traffic patterns, if you can split your devices into two groups <= 7 devices that mostly communicate with each other daisy chaining will work just fine, but if more devices regularly talk to each other and require loads of bandwidth then a single switch with more ports might make more sense.
In most home deployments I know, these theoretical issues typically doe not matter much and selection by convenience form factor just works well.
My internal alarm is, when people call their home set-up a "lab" in which case performance tends to become more of an optimization goal :wink: (but that is correlation, not causation).


Cheers for the replies, in all fairness my networking knowledge is minimal, I'm still on the steep learning curve with Openwrt.

My wireless AP has its own Guest network set up, so that side of things is sorted.

I was only wondering if splitting the AP away from the switch would in help network performance really, currently all traffic from the RPi4 uses a single gigabit connection into the switch, if I added a usb to ethernet adaptor for the AP it would mean, wireless traffic had its own connection so the load would be split between the 2 ethernet connections. I'm not sure if it's a benefit or not.

I will look into the netgear 16 port switches, or I could probably switch a couple of items to wifi and just use a single 8 port item... I have the habit of trying to hardwire as much as possible lol.

Which is good. It means you'll acquire the necessary knowledge very quickly.

A slow acquisition of knowledge, on the other hand, is a shallow learning curve.

The X axis is time, and the Y axis is the amount of knowledge acquired. When the graph is plotted, lots of knowledge acquired in a short amount of time gives a steep learning curve.

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You'd only really face performance issues if your internet connection was faster than this. If not then you're not going to be sending enough data to/from the RPi4 to saturate the gigabit link you already have.


That's what I thought when I originally set it up like this, my internet is only 80/20 vdsl so nothing fancy.

Thanks very much to everyone who replied... It really is appreciated.

No I don't think this would be better at all. It would for example mean all wifi traffic to/from a LAN wired device would be going through the RPi4 cpu and take up a lot of cycles.

Check out the Gs1900-24e from Zyxel it's a reasonable form factor and a lot of ports for ~$100


That makes sense I guess, I never even thought about that side of it...

I'm doing the same thing at the moment, an RPi 4 with a dual USB gigE in addition to the built-in. I have a POE managed switch running 4 cameras and an AP, and a 16 port managed switch for pretty much everything else including NAS and some telecommuting nodes. A dumb trunk takes up a port on each switch, of course.

The PI is connected to both switches, with the third port handling WAN. It's worth doing this way because the Pi is routing several VLANS as well as symmetrical gigabit fiber WAN: eth0 from the RPi goes to the POE switch and handles routed traffic for the default VLAN (including all wifi traffic) as well the private camera VLAN which is not routed to the internet. eth1 goes to the managed switch and handles the DMZ.

It'd be much better to have a single 24 port switch with 8 port POE, I could do everything the same way but instead of a single gigabit trunk I have to worry about saturating -- sometimes bidirectionally for a single stream -- I'd have the whole switch backplane. But other than that it's all good. But I probably would have gone with a single link if it weren't for the routed internal subnets.

I cannot get the dual USB gigE up and running on my rpi4. The first works fine. When I plug in the second I lose the WAN interface and the 2nd gigE doesnt work. TPlink UE300)

Could it be not enough USB power?

What adapters are you using please?

I was using a Vantec dual ethernet adapter. (It was reasonably priced I when I bought it; around $32 US. Still more expensive than a pair of UE300s but worth it to me. For some reason they're much more expensive now.)

Same Realtek chipset and drivers as the UE300, so that shouldn't be the problem.
The RPi4 was powered by the PoE hat.
I don't use this setup anymore -- it worked fine but I had some other requirements come up that needed a different solution.

I can't think of any immediate reason why two Realtek adapters shouldn't work just as well as one.