TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!

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TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!
TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!
2018-07-16 07:16:54
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Hi all,

I've been using a TP-Link TL-PA9020P ethernet powerline adapter kit very successfully with Vivid 200 for many months, always achieving very near to or 200+Mbps internet speed to my Mac Pro, which was great.

However, we have just upgraded to Vivid 350 and my average ethernet Powerline internet speed has actually DECREASED, now never achieving more than 160-170Mbps!

The reported line speed with TP Utility is always c1350Mbps. I realise this is the line speed not the throughput speed, but TP Link have themselves corroborate this with me, that this fast line speed should certainly be able to cope with 350Mbps throughput.

Also using iperf, networking-wise we are seeing c.318Mpbs through the powerline. For internet speeds, when we had Vivid 200 I would regularly get up to 230Mbps through the power line, now we have moved to Vivid 350 it's steadfastly reduced. to c170Mbps

So I contacted TP Link support and reported this rather odd throughput speed decrease via the powerline despite the almost 50% speed increase to the router (confirmed with a test Direct connection and also with a test connection to the spare ethernet socket on Powerline Adapter 1, i.e. the adapter is receiving the full speed also, before is goes through the powerline).

After several days of to'ing and fro'ing with TP-Link support the issue was escalated to their R&D programmers for advice and this is what came back from them:

*************
Sorry for the reply late, I have discussed your issue with our R&D. The communication frequency of Coaxial cable is 5Mhz~42Mhz and the communication frequency of Powerline adapter is 1.8Mhz~68Mhz. So there will be some influence between them, the higher speed of Coaxial cable, the more affected on powerline. So we think your issue may due to this reason.
*************

So they are basically stating that the higher speed Vivid 350 is likely causing more interference than the Vivid 200, to the extent that it has actually reduced the throughout to a LOWER rate than Vivid 200! Wonderful!

Can anybody help to clarify and/or corroborate this claim? i.e. the communication frequency of 200 vs 350 service and affect on powerline adapters?

Virgin Support community state

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The frequencies quoted by TPLink sounded very much like old US Docsis specs for the Upstream and are not correct. EuroDocsis ranges from 5Mhz to 1Ghz which maybe transmitted through the coax (actual frequencies will depend on VM). The VM coaxial upstream is in the range 18MHz to 65 MHz (they may be moving that up to 89 MHz iirc). The VM coaxial downstream is in the range 118 MHz to c. 650 MHz. Unless there is crosstalk from the modem side to the router side (which would corrupt all your router data) what they have said is simply incorrect.
****************

It's seems rather disingenuous that TP-link are now stating their PA9020 Powerline Kit, which they advertise as being their FASTEST adapter, actually has an issue with coaxial supply that makes it perform slower as the speed of the coaxial supply increases past a certain point. Highly annoying at best and false advertising at worst (there is no * /Note anywhere stating anything about coaxial connection issues on their PA9020P kit to ward off customers buying it for it's fastest speeds who are using a fast coaxial-based service service).

I'm wondering whether this is a case of an inherent issue between the coaxial internet supply feed and the way the powerline adapters handle it, or is it interference coming from the cable router and/or coaxial cables in close proximity to the powerline adapter? I’m wondering if it’s the latter whether also finding a more shielded coaxial cables would help matters?

Many thanks in advance and apologies for the long message.
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Re:TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!
2018-07-16 19:19:34
Yeah right ... if your coax cabling had even the slightest bit of a shielding issue, then neither your TV nor your internet service would work properly. PLC (an entire house full of unshielded emitters) is backfiring into cable TV or DSL by orders of magnitude worse than the other way around.

My guess, like yours, is that the TP-Link gear simply falls over itself trying to handle the increased traffic pressure.
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Re:TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!
2018-07-20 01:25:01
Well I did some some pretty extensive testing:
Up until a couple of days ago our network topology was as follows:
ISP(Virgin)---Virgin Hub3---TL-PA9020P(No1.)~~~TL-PA9020P(No2.) —PC2 (Mac Pro Desktop)
In an effort to separate the Hub3 further from the Powerline I added in the gigabit switch, so it is now:
ISP(Virgin)---Virgin Hub3---Netgear Switch(Gigabit)---TL-PA9020P(No1.)~~~TL-PA9020P(No2.) —Mac Pro Desktop (PC2)

In the following iperf tests:
PC1 is my Laptop which I can move around
PC2 is my Mac Pro Desktop setup which is anything but portable and cannot be moved around.

Iperf tests I carried out below to check NETWORK traffic speeds as follows, at no point did I switch off the Hub3 or disconnect it from the gigabit switch. I simply left it in place and did the tests around it. Obviously ensuring the IP addresses on each computer remained the same while testing:
A: PC1 (Laptop)---Netgear Switch(Gigabit)---TL-PA9020P(No2.)—PC2 (Mac Pro Desktop) >>>> 938Mbps / 941Mbps (i.e. not going across powerline network, just testing the switches on the powerline adapter and the netgear switch)
B: PC1 (Laptop)—TL-PA9020P(No1.)~~~TL-PA9020P(No2.)---PC2 (Mac Pro Desktop) : >>>>>> 318Mbps.
C: PC1 (Laptop)---Netgear Switch(Gigabit)---TL-PA9020P(No1.)~~~TL-PA9020P(No2.)—PC2 (Mac Pro Desktop) >>>>> 344 / 362 / 372 Mbps
D: PC1 (Laptop)---(LAN)Virgin Hub3(LAN)---TL-PA9020P(No1.)~~~TL-PA9020P(No2.)—PC2 (Mac Pro Desktop) >>>>>> 295 / 311/ 302 Mbps
E: PC1 (Laptop)---(LAN)Virgin Hub3(LAN)---Netgear Switch(Gigabit)---TL-PA9020P(No1.)~~~TL-PA9020P(No2.)—PC2 (Mac Pro Desktop) >>>>>> 298 / 311 / 321 Mbps

We also know that the coaxial cables are delivering INTERNET traffic to the Hub3 at full speed 350-385Mbs since I connected the laptop direct to hub with Cat6 cable and as expected this gave me immediate full speed of c350-380Mbps.
We also know that INTERNET traffic is reaching PowerLine Adapter No1 at full speed of 350-385Mbos as I just tested that again this morning as follows:
ISP(Virgin)---Virgin Hub3---Netgear Switch(Gigabit)---TL-PA9020P(No1.) Ethernet Port 1 ~~~TL-PA9020P(No1.) Ethernet Port 2 —Laptop (i.e. not going across the powerline network, just into one of the powerline addapters ethernet ports and out the other one).
We know that NON-INTERNET NETWORK traffic can get through the 4 port switch on the Hub3 at speeds between 295-321Mbps as we’ve tested the speed of that switch.
We know that NON-INTERNET NETWORK traffic can get through the gigabit switch at essentially full gigabit speeds 941Mbps
We know that NON-INTERNET NETWORK traffic can get through the PowerLine network at speeds ranging between 344-372Mbps.
We know that INTERNET traffic can only get through the PowerLine network at c170Mbps, i.e. half the speed of the other network traffic.
So, considering all the above, I wonder whether this may shed any further light as to what may be causing the internet traffic download speed to be cut in half while all other traffic remains fast and also causes the slight reduction vs what it used to be at Vivid 200 speeds?

Considering all the tests above I'm just having trouble getting my head around what is happening to the internet traffic vs all the other traffic and where in the system it is happening since all the figures above tend to most or indeed all of my potential hypotheses.

Many thanks for any pointers.
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Re:TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!
2018-07-20 16:32:49
My educated guess would be it's because Internet (download) traffic tends to have lots of reply packets going the other direction - very much unlike local throughput benchmarks that tend to load one direction only.

Powerline is shared-media, so you can only talk in one direction at any given time. So totally unlike LAN where transmit and receive traffic are on separate physical wires, you cannot receive while you are transmitting on PLC.* If you have a managed switch there, you could use its traffic stats to figure out how many packets are being sent and received during (A) those benchmarks and (B) your typical Internet downloads. [You can also use the LAN connection stats on your PC.]

*AV1200 and AV2000 adapters with MIMO enabled could and should be intelligent enough to use one path for Tx and the other for Rx. I'm not at all sure whether they do.
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Re:TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!
2018-07-22 19:50:09
Your powerline adaptors are not aware of what contract you have with Virgin. And it's still Docsys 3 so the frequencies don't change - you just use more channels.

Those link speeds are very low. Make sure you have current firmware and have read the thread about interference on the 9020

Also setup a broadband monitor on Thinkbroadband.co.uk and make sure that it's not a contended service that is the issue.
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Re:TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!
2018-07-23 20:04:52

The Vogon wrote

Your powerline adaptors are not aware of what contract you have with Virgin. And it's still Docsys 3 so the frequencies don't change - you just use more channels.

Those link speeds are very low. Make sure you have current firmware and have read the thread about interference on the 9020

Also setup a broadband monitor on Thinkbroadband.co.uk and make sure that it's not a contended service that is the issue.


Wow. This is definitely news to me (apart from the bit about my powerline adaptors not knowing what contract I have, that much I already knew :-) ).

You say these link speeds are very low? You're not talking about the Line Speed as reported by the TPUtility are you? Cos that is 1350Mbps.

The speeds around 350Mbps are actual network traffic speeds as reported by iperf measured between two computers and according to TPLink support they are exactly what should be expected and they didn't seem to think they were slow at all, or were certainly not letting on if they did.

I have what I believe is the latest firmware as TpLink support even sent me what they said was the latest version, Although I am using V1 Hardware and I'm aware there are V2 and V3 hardwares also. No idea whether those would work better in this situation as again TPLink support didn't give me any information on that question.

I have not seen anything about interference specific to the 9020. TPLink support said they suspect this issue is interference between the coaxial internet supply and the powerline system but they haven't gone into details about it. If you have a link to something specifically about the 9020 I can read that would be much appreciated.

I have setup broadband monitor, What I've seen is a huge swathe of Red complete packet loss all over the place even I times when I'm using the system apparently ok, so I'm not sure whats going on there either.
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#6
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Re:TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!
2018-07-24 00:06:45
If you are getting 350mbits actual transfer speed then you don't have a powerline issue. That's about as good as it gets.

If you have red on a Thinkbroadband monitor then your issue likely lies with virgin media.
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#7
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Re:TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!
2018-07-24 00:43:50

The Vogon wrote

If you are getting 350mbits actual transfer speed then you don't have a powerline issue. That's about as good as it gets.

If you have red on a Thinkbroadband monitor then your issue likely lies with virgin media.


Yes, 350Mbps was (I was told) a pretty decent figure. Hence the original question why is the internet traffic part so slow.

It's definitely not a Virgin issue. At the same time as doing all these tests I always do a direct cable connection check between laptop and router. Always clean as a whistle 350-380Mbps service as per Virgin Vivid 350 service offering. Stick it through the powerline always 170Mbps max. Even TPLink support have got to the stage where they admit It HAS to be an issue between Coaxial Internet electromagnetics and Powerline (since were not talking wifi, were talking wired).

I'm not playing ping pong trying to vapidly blame one or the other. I've provided tests and reports beyond question to try to help Virigin and TPLink work out where the problem lies. As far as I have got, is potential electromagnetic interference between powerline and coaxial. I posted here to see whether anyone could add anything. If anyone knows whether the 9020 V2 or V3 hardware may fare better or have any experience in how to get a powerline (TPLink or other brand) to handle coaxial supply better and not cut it in half even when all other traffic is at 350.

I think the Thinkbroadband graphs are a red herring, just errors in the monitoring of some sort, as I said they've showed Red 100% packet loss even when I'm on the internet patently getting a service so that can't be right. They even have a section talking about that possibility which I still need to read through and make adjustments.

Did you happen to have that link to specifics about 9020 interference? That might be useful.

Cheers
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Re:TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!
2018-07-25 00:49:48
Sounds then like someone didnt read the instructions on configuring their router for Thinkbroadband. Is ICMP enabled?
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Re:TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!
2018-07-26 01:02:10

The Vogon wrote

Sounds then like someone didnt read the instructions on configuring their router for Thinkbroadband. Is ICMP enabled?


I did see that, but it seems Virgin Hub3 doesn't let you set that setting.
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Re:TP-Link PA9020P kit giving REDUCED internet speeds after I upgraded from Vivid 200 to Vivid 350!
2018-07-26 01:31:46

The Vogon wrote

Sounds then like someone didnt read the instructions on configuring their router for Thinkbroadband. Is ICMP enabled?


By the way, please could you possibly direct me towards the thread you mentioned about interference on the 9020?
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