Likely, your cable modem is your router (internal/integrated DHCP server). On most modems, though,(with a single ethernet port), you will need to add a router before a switch. (of course, if you add a router, you may no longer need the switch unless the number of wired devices outnumber the LAN ports of the router).
Additionally, many ISP modems only allow one wired device to access the internet at a time (due to a single public/wan IP address allocation) when using a switch directly connected to the modem. (multiple devices unable to share/compete for this single address in this setup). The router allows multiple devices to share this single IP address. The switch expands the number of wired devices when plugged into the router.
However, just to verify. What is the model number of the cable modem, the ethernet adapter you are using, and the Roku Express (from Settings/System/About).
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First inclination is that the ethernet adapter may be part of the issue since it fails to work at both the switch and the modem location with the Express. Generally, need to use a USB 2.0 10/100 fast ethernet adapter with the required chipsets AX8877X or SMSC95XX. (there are a few users that have reportedly gotten some 10/100/1000 adapters to work, but hit and miss there.)
Sorry for the delayed reply. Here are some answers:
Equipment models:
Cable Modem: Hiltron, Model appears to be EN2251 (This modem has a single ethernet port).
Ethernet Adapter: UGreen Model number on device is illegible; box does not explicitly state model number but shows 30985 and a bar-coded X001C6AUST. (This is the adapter that is linked from the Roku compatibility article).
Roku Express: Model 3960R
Roku Express 4K+: Model 3941R2
Regarding the cable modem, it does seem to latch onto the ID of the particular laptop that is connected to it, and usually has to be re-booted whenever changing from one laptop to another. However, I did try connecting the Roku Express 4K+ directly to the Cable Modem and then re-booting the modem. The Express still could not find the ethernet after that - but possibly the modem did not fully reset because it still recognized the laptop (when the laptop was re-connected directly to the Modem) without another re-boot. (So, the ID of the laptop seemed to be retained by the Modem, despite the re-boot. Possibly, this prevented recognition of the Express).
Regarding the switch, based on what a local "IT guy" said, I was hoping that I could get away with an unmanaged switch, and avoid trying to find an ethernet-only router. Oh, well... The ISP's support rep also seemed to think that a switch was adequate - but didn't sound all that confident.
Regarding the Ethernet Adapters and Rokus, I tried swapping between the two Adapters and the two Rokus when connected via the Switch, but tried only one Adapter and only the Express 4K+ when connecting directly to the Cable Modem. Perhaps I should try the other Adapter and the Express connected directly to the Cable Modem - although all other "test cases" produced identical results. By the way, the Adapters do not indicate which USB protocol they use but are 100 Mbps "fast internet". No idea about their chipsets.
At this point, I'm hoping to find some conclusive identification of the problem before buying more components to "try" - so I hope this isn't going to end up being a matter of "try and see".
Thanks for the info and suggestions!
The Ugreen 30985 ethernet adapter does use the ASIX AX88772C chipset and is the one that is currently linked to from the Roku Support page. https://oemdrivers.com/network-ugreen-30985
Although the product description on the Amazon page indicates it is not compatible with "any Roku devices", I think they mean to say not compatible (technically) with Roku Streaming Sticks. The recommendation/review section indicates users successfully using it with Express 4k devices.
Since it is a compatible chipset and users indicate it does work with Roku devices, you should be good to go with this device. 👍
I have used the Smays ethernet adapter with OTG (for usb storage) with my Roku devices and they work fine (with OTG, allows videos to be played through the Roku Media Player). With this setup, kind of an "improvised" Ultra setup by providing USB to the device.
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The Hitron en2251 is probably your sticking point. It is likely that you have only been issued one IP address. Thus, you can only use an unmanaged switch (or managed switch for that matter) with two wired devices if your ISP issues you two IP addresses (determined by MAC address) when directly connected to a modem.
It may be that the modem is having an issue providing internet access to both the MAC address of the ethernet adapter and the MAC address of the Roku device when directly connected to modem. (basically, a conflict is occuring as only one MAC address at a time can access internet with a single issued IP address.).
However, forgot to ask and just re-read that this is a "new" Express. Have you already setup/activated it? If not, try setting it up using a hotspot or other network before trying the wired method. May just need to get a LAN IP first (this will at least activate the device, but still don't think it will fix the issue you are having.).
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If you are adverse to wifi, then certainly placing a wired router (ethernet-only) after the modem, but before the switch will resolve the issues you are having. If not adverse to having wifi present, then likely any cheap router with the standard 4 ethernet/LAN ports will also resolve your issue.
Your modem has a 2.5G (multigig) ethernet port so depending on your speed plan and your budget, you can decide what type of router to purchase for your needs.
I can confidently tell you that a router (wired or wifi) will resolve the issue you are having and how I would address it. (you can also ask your ISP if they can upgrade your modem to include a combo modem/router if not adverse to wifi capability.) I would just purchase my own router, but laying out the options for you here.
Feel free to update or post more info if still having issues or questions.
For some reason, I was not notified of your second reply, so sorry for not seeing that before my first reply.
A few comments/questions relating to this reply:
Yeah, I noticed that thing about not working with Roku devices in the Amazon listing for the UGreen Ethernet Adapter - but figured that I'd give it a try seeing that it was on Roku's compatibility list. So far, it does appear to be fine with the Express devices - to the limited extent that I can use them so far.
I'll look into that OTG once I get up to speed with the Roku basics. Thanks for the heads-up.
Your assessment of the Cable Modem situation correlates with my observations. (More specifics in my earlier reply).
Also see my earlier reply about the state of activation of my Roku's. Presumably, they have any LAN IPs set up at this point - although possibly they both got the same one. I guess it's worth trying one (or both) again on the Switch at this point - just to see if anything useful happens. As you say, though, it may not really avoid the need for a Router. (Darn!)
I prefer to avoid Wi-Fi for three reasons: 1) potential RF interference with other on-site RF receivers, 2) I prefer to minimize the RF that flies around inside the house (and my body), and 3) Security risks. However, I'm not adverse to getting a router that has Wi-Fi capability that can be disabled (so that only the ethernet can be used) - if that would provide the more practical/economical solution.
My plan speed is 100 Mbps (actually tests around 115 Mbps). I was getting satisfactory results for my laptop(s) using a previous (lower) rate, so I'm guessing that the needs of the Rokus will drive the speed requirements going forward.
At this point, it appears that the buy-my-own-Router route is the more practical way - once I figure out the appropriate Router(s). There seems to be some difference of opinion on whether a Switch can be used successfully to cascade off the Router in order to provide the extra two ethernet ports that I'll need. Seems like it would be right back to the issue of shared IP for the leg to the Switch, though. I'm also curious whether a Wi-Fi Router can serve four ethernet ports simultaneously with two Wi-Fi "ports" - which might be a "sneaky" way to support all six devices (if I can overcome the Wi-Fi aversion). I wonder whether the individual Wi-Fi channel transmitters "sleep" when they're not in use... (Sorry... I am almost completely unfamiliar with Wi-Fi operations).
Thanks for the analysis and suggestions!
Ok, good deal, looks like you are making progress. I will try to do this in some basic steps for you. (if you get lost/confused just post back and I will try to clarify further - no worries).
1. Regarding the Roku activation. Just use your cellphone if you have one (not laptop) in order to proceed through the activation and setup using the phone's web browser.
2. Regarding wifi. Using a wifi router is going to give you the greatest number of options to access a home network and the internet for any connected device. You will be able to connect your cellphone to your network over wifi, any printers, etc. You will not be limited to just having to use wired/ethernet capable devices of connecting to your network.
Wifi routers will also be cheaper normally than a wired router. You can also disable/turn off the wifi 2.4ghz and 5ghz radios and use the wifi router as a wired router. (ie. just use the ethernet ports that will come with the router).
I would personally consider using an AX router (wifi6) since this is a newer protocol and does have some increased security benefits when using wifi (wireless) connected devices. (namely WPA3 authentication). Just note that Roku devices do not currently support the WPA3 security protocol, so your AX router will just have to be configured to also use the more traditional AC (wifi5) WPA2 security protocol. Most AX routers are shipped in this default configuration. Your Roku devices will work with an AX router, just mentioning this as an FYI.
However, since you are wanting to use your Roku in a wired configuration, you will just be plugging it into one of the LAN ports anyways. The WPA2 and WPA3 settings only apply to wireless/wifi connected devices, and does not affect or have anything to do with wired/ethernet connected devices.
3. A wired router will usually cost a bit more but here is a nice starter TP-Link (TL-R605) wired router you can consider for about $60. Here is TP-Link webpage for more detailed info. https://www.tp-link.com/us/business-networking/omada-sdn-router/tl-r605/.
Unfortunately, with a wired network you will need to either add a "wireless access point" or use your laptop as a wireless access point (ad-hoc hotspot) if you ever need to connect a wireless-only device to your network for some reason.
There are a few different methods to add wireless connectivity to a wired network, but for most users, just using a wifi router in their network will provide the easiest method (and less hardware and technical knowledge).
4. The purpose of the router (wired or wireless) is its ability to create a private network. The router will handle all your connected devices (by giving each an independent, private LAN IP address via a DHCP server in the router) and then manage all the network traffic. A router extends the ability for multiple devices to access the internet through a single/public WAN IP address. (some technical NAT operations then occur which directs internet traffic to the proper device and proper sharing).
The router is what allows many connected devices on a network to use/share your internet access (WAN IP address).
Another benefit of the router is that it will usually contain a firewall and other security features that are absent in a modem.
5. Regarding your switch. The switch is just extra ethernet ports. You will plug this switch into your new router (into one of the LAN ports) and now have extra LAN/ethernet ports available. If your router comes with 4 ethernet ports and your switch has 4 ethernet ports, your network now has 7 ethernet ports available for devices to connect to the internet. (one is being used up by the switch).
6. The modem is just the "gateway" to the internet. The router will handle and protect the network traffic (all your devices) and the switch will just allow you to keep adding wired connections to the router.
In any network, if you did not need internet access, you would just use a router and a switch/hub so all the devices on the network could potentially discover and communicate with each other. By adding a modem to the network, you are giving all these devices access to the internet.
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In summary your new setup will look like this... Modem --> Router --> Switch
You can then plug all your wired devices into both the router and the switch. If you need even more ethernet ports, you can either add another switch (preferably to another of the router's LAN port again), or just purchase a switch that has more LAN ports. In practice, you can add a switch to each of the router's LAN ports if you wanted to. The router will know what to do with each switch automatically.
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Hope some of this helps explains some basic networking for you. Feel free to post back if needing more help.
