Poor Powerline Download - G.HN and HomePlug2

[NetGroo]

I have tried both Comtrend G.HN PG-9172 and TP-LINK TL-PA8030 Adapters.

I am getting abysmal "download" speeds (when connecting from the AP attached to them) while my Uploads are decent.

What sort of methods or tools are available for debugging this sort of thing?

I've tried the obvious low hanging fruit: moving outlets, moving closer, unplugging other items, etc etc.
While it gets better closer, it doesn't resolve things totally.

 

[L&LD]

First, you must define 'abysmal' download speeds, including a reference speed you're expecting to get.

 

[thiggins]

First, run the same test with the same devices connected via Ethernet and no AP to get a reference.

Then do the same thing with the AP connected via Ethernet.

There is usually some difference in transmit / receive throughput due to drivers, OS, TCP/IP stack, etc.

 

[NetGroo]

Connection is 40 Mbps down/20 up from the ISP..

Connected to router. No power line I get maybe 35 down, 16 up.
So (DSL) Phone Jack-> Modem -> Router -> IPhone 6 (5G)

Connected with power line in the path I get 2 down, 16 up.
So (DSL) Phone Jack-> Modem -> G.hn Adapter 1 ... G.hn Adapter 2-> Router -> IPhone 6 (5G)

Distance isn't too far for the power line adapters. I've done the test in the same room, different walls with only minor improvement (4d/16u)

So direct, no adapters 35d/16u.
With the same equipment, with just 2 g.hn(or av2, have tried 3 different sets) adapters in the path I get 2d/16u

 

[System Error Message]

i use tp-link power adapters, the one with AV2000 rating and have no issues maxing out my ISP which is 80 down 20 up. There is no wifi in between and i get the same latency whether i connect directly through ethernet or powerline.

If they support encryption, use it as that improves data rates. Make sure they arent loose and use the same pairs. The encryption adds some sort of encoding that helps with data integrity.

I actually have the same arrangement as you have. It could be you have bad cables or something going on with your line. You could use an oscilloscope on the mains socket if it is mains rated so see whats going on. Maybe theres some interference?

 

[sfx2000]

On the TP-Link AV1200's - be aware that TP-Link did push out a firmware release about 6 weeks ago that addressed a number of issues that the devices had - so check their support site... current firmware I have, which is for North America at least is... and the model number I have is PA803oP-Kit (it's the three port models for North America, should be similar to the UK model except for the Mains plug configuration)

1200A-2.0.0.382-05_803111_160328 - remember to flash both files, and this has to be done on each unit directly...

With regards to the PLC config app - setting QoS parameters - need to set it on both ends - it doesn't push from the central coordinator to the remote, so be sure to check both ends there and that they match up.

The PLC app - this one might be market specific, in the US, the preferred version is US_V1_Utility_150423... it's the one with the small green bordered window - TPLink has another version of the utility, but that gave me no end of grief...

FWIW - Encryption is mandatory on HomePlug AV, but one thing to consider is maybe changing the group name from the TP-Link Default (HomePlugAV) to something unique, as there have been reports where this can cause issues (mostly in multiple dwelling units, e.g. townhomes/condos/apartments).

 

[thiggins]

Thanks for running the experiments, NetGroo.

Could be you have some bad noise sources at work. The smaller the power adapter, usually the higher the noise. USB / cell phone adapters can generate a lot of noise. But that doesn't account for
the big difference between up and downlink. It's a puzzler.

Have you tested your wall outlets to be sure they are wired properly and have a good third wire ground?

 

[sfx2000]

And power strips are the bane of powerline - they need to be direct into the mains outlet, and a powerstrip can be plugged behind it, but cell phone chargers, AC Adapters, etc can still impact powerline.

I've found that the Apple chargers are pretty quiet, both the small ones like for iPhone, and the slightly larger ones for the iPads - they're ok for the most part - and Macbook chargers are all clean... (Apple over engineers those items like crazy... 2 dollar answer to a 25 cent question).

My primary concern is that OP has Powerline in the worst possible place - between the Modem ingress and the Router/AP - so any weakness there will be a very big deal that affects all clients on the LAN/WLAN...

And for @System Error Message - on the LAN, PLC does add quite a bit of latency compared to ethernet - see below - gotta love a quantified network - and this is RTT, not single ended...

Ethernet RTT - 94.6 microseconds - and yes, this is a valid number... it's going across a managed switch, so add about 4 microseconds there...

Powerline RTT - 2.5 milliseconds - which would be 2500 microseconds...

 

[System Error Message]

And for @System Error Message - on the LAN, PLC does add quite a bit of latency compared to ethernet - see below - gotta love a quantified network - and this is RTT, not single ended...

Ethernet RTT - 94.6 microseconds - and yes, this is a valid number... it's going across a managed switch, so add about 4 microseconds there...

View attachment 6844

Powerline RTT - 2.5 milliseconds - which would be 2500 microseconds...

View attachment 6845

At first my internet was like this - Internet ---- router modem ---powerline ---- switch. I was getting 6ms in online gaming and ping google from desktop or router showed the same ping in milliseconds, starting at 12ms and dropping down to 10ms consistent for pinging google.

Than switched to internet --- modem --- powerline -- router-- switch, still the same latencies.

Using tp-link's utility shows the PLAs syncing around 800Mb/s so perhaps the sync rate is what determines latency.

To OP, go to tp-link's website, download the utility for your PLA and use it to see the sync rate.

 

[sfx2000]

At first my internet was like this - Internet ---- router modem ---powerline ---- switch. I was getting 6ms in online gaming and ping google from desktop or router showed the same ping in milliseconds, starting at 12ms and dropping down to 10ms consistent for pinging google.

Interesting - maybe it's the tilera processor in the Microtik...

Latency matters...

 

[whsbuss]

Have any of you tried the D-Link DHP-701AV AV2 2000 adapters? My local Microcenter has them on sale for $80 same as the TP-Link

 

[thiggins]

A thought based on SFX's observation. Perhaps the router is adjusting QoS or MTU due to powerline latency. Do you have another router that you could use as an AP? Then put the powerline adapters between the first router LAN and AP?