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AV2 powerline kills my connection, do I need QoS to fix this?

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Rhialto

Senior Member
My PC is wired into a RT-AC1900P and the second wired port is used by a powerline adapter for one of my son computer and when he starts downloading, he's almost killing my connection, my ping gets very bad. There must be a way to avoid this?

I took a look at it once and he was downloading at 5MB/s only, prolly limited by the powerline adapted because we have a faster internet acces than this. And even with that lower download speed, my ping on my end was bad and ruining my gameplay.

I tried looking at QoS but all I see is adaptive or I can manually limit speed on that port but since he's not alrerady getting full speed I guess it won't matter? What are my options? I wish he was not in a dead spot, my other son is on Wifi and all is fine.
 
Both the PC and the PLA are plugged into the router?
 
Probably not downloading at 5MB, that's just an average, it is bursting up, dropping a ton of packets, thrilling back, rinse and repeat. QOS only helps the WAN so probably won't help if that is the case. I'd move to MOCA or even wireless vs PLA.

The router/switch having to drop all those CRC failed frames is likely using CPU to do it and choking on it.

You could try forcing his PC to 10/Half or even 100/Half, that might be enough to avoid so many errors.

Full duplex would be better but you can only do that if the PLA also lets you hardcode, most 10 or 100 devices will not negotiate properly if only one side is hardcoded to full
 
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Probably not downloading at 5MB, that's just an average, it is bursting up, dropping a ton of packets, thrilling back, rinse and repeat. QOS only helps the WAN so probably won't help if that is the case. I'd move to MOCA or even wireless over PLA.

The router/switch having to drop all those CRC failed frames is likely using CPU to do it and choking on it.
A bit what I was also thinking... I was waiting for newer routers to come out to buy a new one and have my 1900P as a mesh. I'm sad that none of the recent announced ASUS routers have all ports at 2.5Gbps. If TP-Link can do it, why not ASUS?
 
A bit what I was also thinking... I was waiting for newer routers to come out to buy a new one and have my 1900P as a mesh. I'm sad that none of the recent announced ASUS routers have all ports at 2.5Gbps. If TP-Link can do it, why not ASUS?
Is the 5MB definitely download? If it is upload, 40Mb may be the limit of your ISP?

If it is download, 5MB/40Mbit definitely implies a bad power line connection and lots of errors.

Even the fact that you've got a 1 gig or even 100M port (depending on the PLA) feeding a 40M capable connection means the switch and router are having to buffer, the buffers will fill quickly and lots of traffic then has to be discarded, slowing everything else connected to that switch down.
 
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I think you should start troubleshooting by temporarily relocating your son's machine to be near the router and plugging it directly in with an ethernet cable. How does his download speed look then, and is there still a performance problem for concurrent network use? If that fixes it, you know that it's the PLA at fault and can start to look for an alternative connection method for his computer. If it doesn't fix it, you've got a different issue to solve.
 
Go to a garage sale. Buy a cheap router. One that has Media Bridge mode.

Connect to your main router in Media Bridge mode, plug in your son's computer to the Media Bridge.
 
Go to a garage sale. Buy a cheap router. One that has Media Bridge mode.

Connect to your main router in Media Bridge mode, plug in your son's computer to the Media Bridge.

Or even depending on the distance, a good wireless card with external antennas might be enough. If not, then yes a repeater about halfway between. Of course if the signal strength isn't good, it would still end up slowing things down but you could put it on the 2.4G band and hopefully not impact your wired or 5ghz connections as much.
 
My PC is wired into a RT-AC1900P and the second wired port is used by a powerline adapter for one of my son computer and when he starts downloading, he's almost killing my connection, my ping gets very bad. There must be a way to avoid this?

I tried looking at QoS but all I see is adaptive or I can manually limit speed on that port but since he's not alrerady getting full speed I guess it won't matter? What are my options? I wish he was not in a dead spot, my other son is on Wifi and all is fine.

Enable Adaptive QoS - that's a start - since you and him are contending for the same WAN resources and each connection (and there may be many, see netstat output), those are all network flows - so yes, Adaptive QoS could help here...

I wouldn't "limit" his connection, as this doesn't really fix the issue at hand.

Some of the other advice offered, e.g. wireless bridge, isn't going to change anything - as I mentioned, it's not the bandwidth, it's the traffic across the bridge, and WAN side will definitely be helped with QoS in place - that's why it's there...
 
Enable Adaptive QoS - that's a start - since you and him are contending for the same WAN resources and each connection (and there may be many, see netstat output), those are all network flows - so yes, Adaptive QoS could help here...

I wouldn't "limit" his connection, as this doesn't really fix the issue at hand.

Some of the other advice offered, e.g. wireless bridge, isn't going to change anything - as I mentioned, it's not the bandwidth, it's the traffic across the bridge, and WAN side will definitely be helped with QoS in place - that's why it's there...

The issue doesn't sound like WAN contention at all. If anything QOS would probably hurt things by putting even more load on the router, which from what it sounds like, already has overflowing buffers.

The issue is very similar to WAN contention except it is on the LAN. Any time you have a physical interface rate that is higher than the throughput capacity, you're going to experience buffer issues. My guess is the switch in these routers probably only has one buffer and ASIC for all the ports. Then on top of that, the powerline connections likely being very poor and having lots of drops due to CRC failures and retransmissions compounding the issue, I'd be willing to bet that a wireless repeater would be superior to the powerline connection, and as long as the signal strength is good should make a big difference, or potentially even mostly solve the issue.

Rate limiting the LAN connection at the client end could also improve things in this scenario, but is not the best solution since you're still going to be choking a 1G connection on the router side down to something smaller, but it may at least alleviate a lot of the errors. If you can set the port on the router to 10/Full along with the powerline adapters and the PC, that would be ideal. Router I think needs a script, PC can be done in the card properties, but the PLAs may not allow it.
 
Not a bandwidth issue. QoS has nothing to do here on LAN. A test what @tgl is saying will reveal if PLA is causing it. If not - attention to PC's NIC.
 
Not a bandwidth issue. QoS has nothing to do here on LAN. A test what @tgl is saying will reveal if PLA is causing it. If not - attention to PC's NIC.

Go back and read OP's first post - this issue occurs when his kid is downloading...

It's a WAN issue - QoS likely will help.
 
Go back and read the same post carefully. :)
The kid is downloading slower than ISP line speed and limited by internal network factors.

The PLA has nothing to do with his problem though - it's just another ethernet port to the router/switch on the LAN side.

Think this through very carefully (or maybe not, you could be "overthinking it") - PLA's are layer 2 devices, so what going into the HomePlug stack is what comes out on the other end - ethernet frames...

QoS isn't going to hurt OP - esp if he's uplink limited... this is absolutely the use case for QoS on the WAN/LAN bridge, to keep any one flow from dominating things
 
PLA's are layer 2 devices, so what going into the HomePlug stack is what comes out on the other end - ethernet frames...
Yeah, but if frequently nothing comes out the other end, retransmissions and buffer bloat might account for the observed side-effects on other activity. I still think the OP's first order of business ought to be to test what happens with the PLA taken out of the picture.
 
The PLA has nothing to do with his problem though - it's just another ethernet port to the router/switch on the LAN side.

Think this through very carefully (or maybe not, you could be "overthinking it") - PLA's are layer 2 devices, so what going into the HomePlug stack is what comes out on the other end - ethernet frames...

QoS isn't going to hurt OP - esp if he's uplink limited... this is absolutely the use case for QoS on the WAN/LAN bridge, to keep any one flow from dominating things

The PLA likely has everything to do with the problem. The exact same reason people run QOS on the WAN comes into play here (physical connection speed is larger than actual connection speed, and bandwidth is being saturated). On top of that PLA are subject to really lousy connection quality resulting in errors and retransmissions further exacerbating the problem.

Given the low end switch in these routers, an overflowing buffer and constant CRC discards will likely impact everything connected to the switch.

In other words, the problem is on the LAN side and WAN QOS isn't going to help that, assuming the OP is correct that the bandwidth is in the download direction and definitely is not saturating the internet speed.
 
Just a quick note to say thank you everyone. I'm still here and reading all posts, trying to understand it all. I just haven't done any testing. Sure turning QoS on is only a click away but before doing that I will try to find dedicated time to test and not just turn it on and see in a week if I saw a difference that could be hard to spot because I don't know what my son is doing.

I will have time to do some dedicated testing in 2 weeks only. Because you were many to reply, so I take it as interested in this issue, I'll report when done. I may even push testing a bit further by testing both PLA I have, one is AV2 and one is G.hn. From previous testing I know the G.hn was outperforming the AV2 in both download/upload but my son was reporting some issue when gaming so I've decided to put back the AV2 and see if it's better for him. I don't hear from him about issues like before but now it's me who experience issues.
 
PLA's are layer 2 devices, so what going into the HomePlug stack is what comes out on the other end - ethernet frames...

Agree - if the PLA are working properly. The doubts here are PLA in question are not working properly and causing the issue.
 

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