Connecting router to modem via Powerline, how bad an idea?

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preacher65

Regular Contributor
Have been holding off replacing my router as I wanted to build an AIMesh system, but can't see any realistic options in this house for a wired backhaul, so a tri-band router to support wireless backhaul seemed the way to go. However I'm so used to having an Asus router running Merlin that I think I'd regret anything else, and until recently there were only dual-band routers with Merlin support.

I've seen recently that Merlin is now available for the GT-AX1100, so was considering that as the main router, but it's so big! It's a typical UK house, with the VDSL line coming into the entrance hall - my AC86U just about fits on a small shelf, but there's no way I'd fit a ROG router on there, and even if I could, I'd probably be slaughtered if I proposed putting such an ugly thing where it would greet everyone who comes to visit. :)

The obvious answer seems to be to move the router somewhere else, leaving just the modem in the hall. With concrete floors on the ground floor, running ethernet around the house doesn't really seem practical. All I can think of is to connect the modem to the router over Powerline, but that seems like it's likely to result in a degraded internet experience.

I can experiment with my existing equipment (I have some Devolo Magic 2 Powerline kit already) but wondered if anyone has any experience of connecting a router to a modem over Powerline? Is it likely to be as bad as an idea as it seems?

Is there some other option I'm missing here - if I use dual-band kit for the mesh, is Powerline viable backhaul? Seems like that would introduce latency and throttle the bandwidth between the nodes.


A short note on use cases -
Internet - my broadband only delivers around 35-40Mbps. I don't do a lot of online gaming, but like many others now I work from home and rely heavily a solid VPN connection, with various internet breakouts for services such as Teams and 365. So internet bandwidth is unlikely to be capped by Powerline, but I don't want to introduce a lot of latency into every device's connection to the internet.
Home network - a few PCs/laptops, several mobile devices, some IoT, a Plex media server and a NAS. We're not chucking vast amounts of data around, but it'd be nice to realise decent bandwidth from clients to the NAS. I only have a few Wifi 6 clients so far, but doubtless more to come, and the NAS would probably be connected by ethernet to a mesh node if I go that route.
 

thiggins

Mr. Easy
Staff member
Powerline should be able to provide 50 Mbps with low latency. I'd give it a try.
 

eibgrad

Very Senior Member
The issue w/ powerline is that it's *very* hit and miss. Sometimes it doesn't work at all. Other times adequately for the intended task (e.g., supporting HD streaming for the TV). And sometimes it's just awesome. The only way to know is to try it.

Even within my own environment, performance varies widely. It works everywhere, but you can literally plug it into an outlet a few feet away and have a dramatic increase/decrease in performance. And distance from the base adapter (i.e., the one patched to your modem/router) rarely seems to be the issue. Sometimes the best performers are on the other side of the house! I assume line noise is the primary culprit.

It's not perfect, but can be a lifesaver at times.
 

preacher65

Regular Contributor
Thanks for the replies - appreciate the feedback that it's worth a try at least. Bearing in mind it's likely to depend on which mains sockets (outlets) I choose, I started experimenting today. (Apologies for the long post.)

Firstly I connected a Powerline at the router's probable new location, and plugged in a test device. I set a ping going both to the router and the test device, over a fairly long period. At any given time the average difference in response time due to that extra hop over Powerline was about a millisecond, and it seemed fairly consistent over an hour or two.

Then I moved the router and connected it as
Modem<==Powerline==>Router
All seemed fine there as well in terms of internet connectivity, though I'd have liked to test for longer to see how stable and consistent it is. (e.g. Does line noise vary throughout the day/week?)

I wasn't able to leave it set up that way for longer term testing though. I had to move a few other things around to make this setup work, including disconnecting my Sky Q (satellite/streaming TV service) main box. This needs an internet connection, which I'd been providing from a Powerline connection to the router. I disconnected it from Powerline and connected it instead to an R7800 I have running as a LAN/WLAN bridge using OpenWRT.

The main box seemed happy enough, but Sky Q also has subsidiary "mini" boxes, and these connect to the main Q box via their own proprietary 5GHz mesh. This has been working fine for a year, the mini boxes connected to the internet as follows and don't use my normal wifi at all:
Mini box<==5GHz Sky Mesh==>Main box<==Powerline==>Router
In this config, the mini boxes show as ethernet connected clients on the router, and pick up IP addresses from DHCP, but I can't ping them. They show as internet connected in the Sky interface.

I took out the Powerline and changed that to use the LAN/WLAN bridge as follows:
Mini box<==5GHz Sky Mesh==>Main box<==Ethernet==>Bridge<==5GHz normal wifi==>Router
and although the main box works fine, the mini boxes stopped working, and none of them show as connected clients on the router, and the mini boxes fail internet connectivity self-tests.

I suspect that's probably a topic for another post, if I can't get it working on my own, but posting it here just in case any knows why it's doing that...

So anyway, assuming I can sort the Sky Q TV issues out, I'll move everything back for a longer term test of the Modem<==Powerline==>Router config, before making decisions about new hardware. It has occurred to me that just moving the router to a more central location in the house will be a big step forward...
 
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