The "powerline is low latency" myth

[skywake]

I see this posted all the time on the forums. People just keep repeating this idea that powerline is as good as straight Ethernet in terms of latency. Without any reasoning behind it other than a belief that it is because "it's wired". So this is a short rant thread, with evidence, showing how that's a load of bull. Science! Firstly the numbers straight from my own setup.

 

edit: updated with a better graph

Ethernet

50 packets transmitted, 50 received, 0% packet loss, time 49063msrtt min/avg/max/mdev = 0.840/0.962/1.254/0.084 ms

WiFi (N150 netbook on an AC1200 AP) 

50 packets transmitted, 50 received, 0% packet loss, time 49090msrtt min/avg/max/mdev = 1.511/2.141/9.584/1.254 ms

Powerline (AV200):

50 packets transmitted, 50 received, 0% packet loss, time 49081msrtt min/avg/max/mdev = 3.747/4.817/20.578/2.413 ms

And for the more visual people? Here's that same data in a graph, the average and the variation on either side:

 

 

If others have a different experience? Please ping your router, prove me wrong. Maybe my setup is unusual in some way or something odd is happening. Because both wireless and powerline are very much influenced by where they are deployed. That said I have consistently got the same sort of results every time I've tested it with all sorts of different gear. And in the videos where I've seen people test the latency of powerline? Their numbers also match up with mine. So I think it's pretty clear cut.

 

Don't get me wrong, powerline has a place. It's a good piece of networking tech to reach wireless blackspots if you don't want to run Ethernet. And when you get to the point where WiFi is starting to drop out powerline will still be chugging along. But don't sell it for things that it isn't. Powerline is not going to give you lower latency. If you're going to give advice give good advice, don't just repeat what you think is true.

Edited September 9, 2015 by skywake

[Liam-McShane]

 

 

If others have a different experience? Please ping your router. Maybe my setup is unusual in some way or something odd is happening. But consistently I have got the same results everytime I've tested it. And in the videos where I've seen people test the latency? Their numbers also match up with mine. So I think it's pretty clear cut. That said powerline has a place, it's a good piece of networking tech to reach wireless blackspots if you don't want to run Ethernet. But don't sell it for things that it isn't.

 

I had the same experience too. I've had nothing but trouble with them, hence why I switched to Wi-Fi.

[ZetZet]

Only drawback of wi-fi in my eyes is the fact that upload speeds are cut down.

[Zeke]

And when you get to the point where WiFi is starting to drop out powerline will still be chugging along.

Nonsene, that simply means you need a more powerful transmitter.

[skywake]

I had the same experience too. I've had nothing but trouble with them, hence why I switched to Wi-Fi.

Well it has some value and they all have their strengths and weaknesses. The point is people shouldn't think of it as a low-latency alternative to WiFi or a substitute for Ethernet. And that if they're going to say something does something they should be able to back their claim up with evidence.

 

Nonsene, that simply means you need a more powerful transmitter.

Walls get in the way of WiFi and Powerline doesn't care about walls. Especially thick walls or large metal surfaces. Odds are if you have a room where the WiFi reception is horrible then powerline will give you better performance regardless of how good your access point is.

 

And a better access point can only do so much, there's a reason why larger areas use lots of tiny access points rather than a couple of big ones. Again, from personal experience I've seen this. It didn't matter how many times I upgraded my single wireless access point I could never get reception out the back. But that's a thread for another day!

[Zeke]

Walls get in the way of WiFi and Powerline doesn't care about walls. Especially thick walls or large metal surfaces. Odds are if you have a room where the WiFi reception is horrible then powerline will give you better performance regardless of how good your access point is. And better a access point can only do so much, there's a reason why larger areas use lots of tiny access points rather than a couple of big ones. But that's a thread for another day!

I'm talking about a really powerful transmitter, maybe 100-200W of power. For better coverage you may as well put it on a drone.

[skywake]

I'm talking about a really powerful transmitter, maybe 100-200W of power. For better coverage you may as well put it on a drone.

And at that point you should probably just run Ethernet anyways.....

[arronleeds]

linus did a video on this, powerline beat wireless and ethernet beat powerline, but.....

 

my house wiring is shite, so it goes ethernet>wifi>powerline.

[skywake]

linus did a video on this, powerline beat wireless and ethernet beat powerline, but....

Well yeah, they did and the video is on the NCIX channel. And they did also make the conclusion that powerline was "lower latency" than WiFi which was "better for gaming". But watch the video and see the pings. In that same video this is what was actually on the screen for average pings:

 

Ethernet: <1ms

Wireless: 1ms

Powerline: 3ms

 

not far off what I measured.

[brwainer]

I have an extensive monitoring system set up on everything in my house, so I have this data to offer:

-firstly, my network consists of a gateway switch that connects three routers (true routers, none of them do wireless) to the Verizon FIOS ONT (I have five static public IP address). Router A has a gigabit ethernet connection to a switch and an AP. Router B and Router C both connect to the same powerline adaptor (each router's LAN is on it's own VLAN). There is a powerline adaptor and a switch in the living room on the B VLAN. There is a powerline adaptor and a switch in one bedroom on the C VLAN, and a powerline adaptor and an AP in another bedroom (this AP has two SSIDs, one for each VLAN)

-all hardware is less than one year old, and has gigabit ports. My Powerline adaptors are Zyxel Homeplug AV2 600Mb units

-pings from Router A to the switch connected by gigabit are 0.34ms average, with spikes to 0.53ms

-pings from a device on the Router A AP to Router A are 4ms average, with spikes to 80ms most of the time and occasionally to 145ms (no correlation yet)

-pings from Router B to the living room switch (over powerline) are 4ms average with spikes to 8ms usually, but there are times when pings get to 500ms. These appear to correlate with when the clothes dryer kicks on.

-pings from Router C to the bedroom switch (over powerline) are 3ms average with spikes to 6ms usually, but there are times when pings get to 400ms. These appear to correlate with when the oven kicks on.

-pings from Router B or Router C to the AP (over powerline) are 5ms average with spikes to 10ms usually, but there are times when pings get to 500ms. These appear to correlate with when the oven kicks on.

-Pings from devices on the powerline AP to either router are 6ms average with spikes the same (and at the same times) as the AP itself (there is some additional spikes related to the wireless as well)

This is what I have come to understand: Powerline is about equal to modern wireless when looking at purely average ping times. However when you look at the max times and standard deviation, powerline wins most of the time. But when something power hungry kicks on, powerline may take a short connectivity hit. Note that I only compare modern powerline to modern wireless, my understanding is that early powerline did have a decent lead in latency over Wireless G, but I do not know that for sure.

[Dubesta11]

I have used powerline adapters in a few different situations. One of my friends lives in a concrete house with the router in the basement, and he lives on the top floor. He bought a good wifi adapter and it still could not hold a constant signal. I told him to get a powerline adapter and his speeds/ping has increased dramatically.

 

I also use one in my house to connect to a TV since it cannot pick up the wifi signal across the house with good download speeds for netflix. Wifi can also be unreliable at times, and a few extra ms ping is not going to have a huge impact for gaming.

[d33g33]

Interesting, Im just investigating powerline adapters now. Whats funny is @skywake 's involvement in this thread. What I find amusing about is as I have just moved to Perth from Melbourne. What is different about Perth is all internal walls of a house over here is brick rather than timber frame. (because of white ants apparently)

 

WiFi through brick walls is a bit of a challenge. I'm trying to figure out if I go UniFi WAP or Powerline...

[Benji_w]

I use power line as the wifi is out of range to be usable, my brother has his pc above the router and has mega wifi strength... Yet every game we play online either solo or together, i get the best results.

 

I have good wiring here and one of my powerlines is plugged into a multiplug adapter sooooooo...  :huh:

[thekeemo]

5ms powerline 40 wifi

[skywake]

It's worth pointing out again that WiFi does degrade faster than powerline. Also that different people's setups will cause different results. Things like interference and the amount of traffic on the network, particularly for WiFi and Powerline, will seriously hit pings. There's no question at all that getting good wireless coverage can be a pain. There's also no doubting the obvious fact that when you're on the fringes of your WiFi network performance goes to shit. But that's not what I'm talking about. What I'm talking about is the idea some people have that Powerline is automatically better than WiFi in terms of latency. Or even that it's as good as Ethernet. Which is completely wrong.

 

Interesting, Im just investigating powerline adapters now. Whats funny is @skywake 's involvement in this thread. What I find amusing about is as I have just moved to Perth from Melbourne. What is different about Perth is all internal walls of a house over here is brick rather than timber frame. (because of white ants apparently)

Definitely. I used to have all of my networking gear in the front room of the house which is brick internal walls and double brick external. The Wireless signal would have had to travel through 4 internal walls, one external, a fridge and about 20m to reach the room where I did this test. When it was like that there was no contest, I could barely get any wireless connection at all but the powerline adapter performed just as well as it does now. Any stable connection was better than WiFi.

 

But now I've moved everything around? Everything is pretty much working as well as it can. And now that everything is performing as well as it can Powerline is higher latency. In a nutshell it starts off with Ethernet being the lowest latency followed by WiFi then Powerline. Then eventually you get to the point where WiFi turns to shit and powerline overtakes it.

[You_are_a_cunt]

Here I sit, smug face and all, buried in over 200m of Cat6e waiting to be installed throughout the apartment.

[d33g33]

It's worth pointing out again that WiFi does degrade faster than powerline. Also that different people's setups will cause different results. Things like interference and the amount of traffic on the network, particularly for WiFi and Powerline, will seriously hit pings. There's no question at all that getting good wireless coverage can be a pain. There's also no doubting the obvious fact that when you're on the fringes of your WiFi network performance goes to shit. But that's not what I'm talking about. What I'm talking about is the idea some people have that Powerline is automatically better than WiFi in terms of latency. Or even that it's as good as Ethernet. Which is completely wrong.

 

Definitely. I used to have all of my networking gear in the front room of the house which is brick internal walls and double brick external. The Wireless signal would have had to travel through 4 internal walls, one external, a fridge and about 20m to reach the room where I did this test. When it was like that there was no contest, I could barely get any wireless connection at all but the powerline adapter performed just as well as it does now. Any stable connection was better than WiFi.

 

But now I've moved everything around? Everything is pretty much working as well as it can. And now that everything is performing as well as it can Powerline is higher latency. In a nutshell it starts off with Ethernet being the lowest latency followed by WiFi then Powerline. Then eventually you get to the point where WiFi turns to shit and powerline overtakes it.

Fair enough, we move into our house one the weekend, we'll see how the AC86U does in there, I believe you can actually throw more power at the wireless broadcast on this router. I'll have to sewe where we stand after that

[LinusTech]

Well yeah, they did and the video is on the NCIX channel. And they did also make the conclusion that powerline was "lower latency" than WiFi which was "better for gaming". But watch the video and see the pings. In that same video this is what was actually on the screen for average pings:

 

Ethernet: <1ms

Wireless: 1ms

Powerline: 3ms

 

not far off what I measured.

 

IIRC my conclusion was that my pings were more CONSISTENT with powerline than with wifi. 

But I didn't re-watch it.

[YT2002]

IIRC my conclusion was that my pings were more CONSISTENT with powerline than with wifi. 

But I didn't re-watch it.

Hello Mr Tech Tips

[skywake]

IIRC my conclusion was that my pings were more CONSISTENT with powerline than with wifi. 

But I didn't re-watch it.

Watching it again I see where I got confused. You went from talking about pings and how they were more consistent straight into the conclusion. With no pause. I don't necessarily agree with the consistency point either BTW, a sample size of 5 isn't exactly very science. But I won't harp on about it too much and will instead draw everyone's attention to the date that video was uploaded. And now we all feel old.

 

Maybe a more updated follow up video would be nice. Quite a bit has changed since that video was made.

[roastduck]

It's also worth pointing out that a building's wiring will have a big effect on powerline signal

[Bittenfleax]

It's also worth pointing out that a building's wiring will have a big effect on powerline signal

Was just about to say this.

 

What if you have a much shorter path and what if you have a really old house with lower grade copper? What if you have a modern house with high grade copper and wiring is the shortest to be most efficient? 

 

Different countries have different standards with wiring.

 

It will all change depending on your house.

[skywake]

It's also worth pointing out that a building's wiring will have a big effect on powerline signal

I think that's kinda beside the point here. Sure it's kinda hard to quantify what "good wiring" is and if you want to you could write off my numbers as being a result of that. But I haven't had any issues with that powerline adapter. If I was trying to be as fair as possible I would say that it was working pretty well. As was the wireless signal. Thus my conclusion was that Wireless starts out ahead of powerline and that Powerline is well behind Ethernet. Though I did defend powerline by saying that it tends to stay where it is for longer than WiFi

 

But I think the real telling thing are the other numbers that have been posted here. There are some really crap numbers for wireless, some of which were far higher than the numbers I got. With huge variation. That doesn't sit nicely against the conclusion I made. The only explanation I can think of is that I had zero interference, a fantastic signal and pretty much zero other traffic. The powerline numbers? All of them have lined up with what I posted.

 

I might come back later with some better stats. Do a few hundred pings on both, table the results. Maybe min, max, median, Q1, Q3 will give a clearer picture of what I'm seeing here. And for good measure I'll go into the back shed and test wireless there. For comparison.

[Wombo]

Only drawback of wi-fi in my eyes is the fact that upload speeds are cut down.

WiFi is symmetric is it not?

[d33g33]

I used Powerline tech about 6 years ago, it worked, but was flakey and then stopped working and no matter what i did it wouldn't come back.

 

I'm pretty sure i'm going to have to revisit it in the new house, but will be sure to hang onto receipts for warranty this time...