[SOLVED] Powerline adapter speed drop

Oct 7, 2020
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Hi,

I just got my new internet form telekom. Its supposedly a 2Gb connection over optical cable and the router i got can transmit it over 2 ports 1000/1000. Since the living room is quit tricky to run wires from the router i got myself a powerline adapter ( zyxel pla5456) that should handle the 2port communication up to 1800mbps and that should be more then enough since the provider willl never actualy handle 2Gbps. The plan was to connect the router directly to the powerline adapter and plug it in the wall, then in the living room also directly in the wall the other one then connect that to a switch over 2 ports and the switch can distribute it to all the hardware that needs it in there. I had two problems. One: the speed i can measure with speedtest drops to ~120mbps over the powerline opposed to ~950 from a direct link with the router. Two: when using the powerline adapter with the switch i get disconnects on random devices while others on the same switch are still connected. Problem one is surely the powerline adapters fault, when i connect the router to the switch the speed stays the same, but problem two can be the switches fault too.
Soo tldr; the questions:
Can it be that the powerline adapter simply looses that much speed due to bad cables in the walls, to much noise? Answered by bill001g. -yes
Can it be that i set something up wrong and the switch doesnt recognize the 2 port connection?
Why do some devices lose connection while others stay connected?
Do i have to change something on the router/powerline adapter/switch to get the dual port communication set up? Answered by bill001g. -powerline is half-duplex
Does setting up a LAG for the two ports going to the router on the switch help at all? Answered by bill001g. -could help not guaranteed due to the algorithm used.

Specs:
router: https://media.telekom.ro/images/docs/Legal_docs/Fix/Specificatie_Tehnica_ONT.pdf
powerline adapter: https://www.zyxel.com/products_services/2000-Mbps-HomePlug-AV2-Powerline-Pass-Thru-2-Port-Gigabit-Ethernet-Adapter-PLA5456/
switch: https://www.tp-link.com/en/business-networking/easy-smart-switch/tl-sg108e/
Connected devices: 1 PC, 2 laptops, 1 TV

EDIT:
Also, just checked the manufacturers software shows an out/in ~500mbps on the powerline adapter while speedtest measures ~120 on the pc connection where does the rest go?:)

Thanks,
Chris
 
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2 possible things will happen if you hook 2 cables between the modem/router and a switch. You will get a massive broadcast loop that will crash the switch and or router. Traffic send out port 1 gets send back on port 2 and round and round.

The router or switch is smart and is running something called spanning tree used to prevent loops. It will disable one of the 2 ports and it will function as though you only had 1 cable.

You need a switch that support port aggregation to even consider this. I really hate port aggregation and was so happy when it was no longer needed in commercial installs. So many times the ports would get confused and strange stuff happen. One side would run port aggregation and the other wouldn't but since it though it was to be aggregated spanning tree was off. You would randomly get massive network loops that would crash whole buildings.

.....Are you even sure that router support port aggregation does no good to buy a switch if the router does not.

I would see what happens if you were to plug 2 machines directly into the router and run speedtest on both at the same time. In theory both should show 1gbit rates. I strong suspect if this is like other GPON installs that are similar the cable company is not telling the whole story. Many times they including the speed used by cable tv on the same fiber in their rates. They are quoting the rate of the fiber media not the rate they deliver. Hard to say some ISP are very dishonest.
 
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You need to learn how the technology works rather than just looking at the big numbers in the headline.

I am unsure why they call those units 2000. They are based on a homeplug standard that is called av2-1200. Powerline numbers are like wifi numbers they are pretty much lies. Maybe you should use the new improve cat5e cable that can run 2gbit. But all 1gbit ethernet ports work that way, they just do not do stupid stuff like add the transmit and receive speeds together. Ethernet unlike other technologies can actually really run 1gbit up and 1gbit down at the same time. Wifi and powerline are half duplex. So they can't actually transmit and receive at the same time and at high traffic loads with mulitple nodes they degrade each others traffic because they have data collisions.

You should get a little bit better on powerline av2-2000 most people get closer to 300mbps but it is extremely dependent on your house wires.

The only technology that can come close to ethernet is MoCA. The 2.5 version can actually get gigabit speeds. It still though can't actually send 1gbit and receive 1gbit at the same time like a ethernet cable.

You are going to have massive issue actually trying to use a bonded connection and get full speed out of it even using all ethernet cables. The industry standard LAG uses a mathematical method to load balance. It does not care about utilization so it might but all the traffic on one connection and leave the other idle. In addition a single session can not use both connections. So even if you were to plug a dual nic pc directly into the modem and setup LAG it would still only see speedtest numbers of 1gbit. Now if you work at you might be able to run 2 speedtest session and get them to show but it is kinda luck it might put both session on the same cable leaving the other unused. There are some proprietary forms of LAG that try other method to distribute the data but many suffer from out of order data packets which increases the load on end deices and many times is can cause data loss because the end device do not know the out of order packet was out of order until they receive it. In general most equipment if it even has support for LAG supports the 802.3ad form.

Pretty much the use of port aggregation was when you have many end clients access some central server. The randomness of the ports/ip will cause better utilization of both connections but you have to have a larger number of clients just a few and you get unequal utilization. This is partially why that servers went to 10g ports even when they were very expensive. You seldom see port aggregation used in data centers any more, it is only the home user chasing this old technology. The best solution is to have 10g ports on the router and the pc.
 
Oct 7, 2020
3
0
10
0
You need to learn how the technology works rather than just looking at the big numbers in the headline.

I am unsure why they call those units 2000. They are based on a homeplug standard that is called av2-1200. Powerline numbers are like wifi numbers they are pretty much lies. Maybe you should use the new improve cat5e cable that can run 2gbit. But all 1gbit ethernet ports work that way, they just do not do stupid stuff like add the transmit and receive speeds together. Ethernet unlike other technologies can actually really run 1gbit up and 1gbit down at the same time. Wifi and powerline are half duplex. So they can't actually transmit and receive at the same time and at high traffic loads with mulitple nodes they degrade each others traffic because they have data collisions.

You should get a little bit better on powerline av2-2000 most people get closer to 300mbps but it is extremely dependent on your house wires.

The only technology that can come close to ethernet is MoCA. The 2.5 version can actually get gigabit speeds. It still though can't actually send 1gbit and receive 1gbit at the same time like a ethernet cable.

You are going to have massive issue actually trying to use a bonded connection and get full speed out of it even using all ethernet cables. The industry standard LAG uses a mathematical method to load balance. It does not care about utilization so it might but all the traffic on one connection and leave the other idle. In addition a single session can not use both connections. So even if you were to plug a dual nic pc directly into the modem and setup LAG it would still only see speedtest numbers of 1gbit. Now if you work at you might be able to run 2 speedtest session and get them to show but it is kinda luck it might put both session on the same cable leaving the other unused. There are some proprietary forms of LAG that try other method to distribute the data but many suffer from out of order data packets which increases the load on end deices and many times is can cause data loss because the end device do not know the out of order packet was out of order until they receive it. In general most equipment if it even has support for LAG supports the 802.3ad form.

Pretty much the use of port aggregation was when you have many end clients access some central server. The randomness of the ports/ip will cause better utilization of both connections but you have to have a larger number of clients just a few and you get unequal utilization. This is partially why that servers went to 10g ports even when they were very expensive. You seldom see port aggregation used in data centers any more, it is only the home user chasing this old technology. The best solution is to have 10g ports on the router and the pc.
Damn i had no idea they werent full-duplex.. So basically im [insert swear word here ] with the powerline adapter stuff :s
But theoretically if i run 2 really long cat6 cables directly to the switch from the modem, leave the ports as individual full-duplex (not using LAG) then 2 different devices connected to the switch could have 1-1 gbit of bandwidth since (according to the provider) the optical handles 2gbit right? Or at least it would have the chance if the algorithm decides to put the packages on 2 different ports. Or am i completely missing the point here? (Sorry, i was always bad at the networking classes :D and thanks for the help.)
 
Last edited:
2 possible things will happen if you hook 2 cables between the modem/router and a switch. You will get a massive broadcast loop that will crash the switch and or router. Traffic send out port 1 gets send back on port 2 and round and round.

The router or switch is smart and is running something called spanning tree used to prevent loops. It will disable one of the 2 ports and it will function as though you only had 1 cable.

You need a switch that support port aggregation to even consider this. I really hate port aggregation and was so happy when it was no longer needed in commercial installs. So many times the ports would get confused and strange stuff happen. One side would run port aggregation and the other wouldn't but since it though it was to be aggregated spanning tree was off. You would randomly get massive network loops that would crash whole buildings.

.....Are you even sure that router support port aggregation does no good to buy a switch if the router does not.

I would see what happens if you were to plug 2 machines directly into the router and run speedtest on both at the same time. In theory both should show 1gbit rates. I strong suspect if this is like other GPON installs that are similar the cable company is not telling the whole story. Many times they including the speed used by cable tv on the same fiber in their rates. They are quoting the rate of the fiber media not the rate they deliver. Hard to say some ISP are very dishonest.
 
Last edited:
Oct 7, 2020
3
0
10
0
2 possible things will happen if you hook 2 cables between the modem/router and a switch. You will get a massive broadcast loop that will crash the switch and or router. Traffic send out port 1 gets send back on port 2 and round and round.

The router or switch is smart and is running something called spanning tree used to prevent loops. It will disable one of the 2 ports and it will function as though you only had 1 cable.

You need a switch that support port aggregation to even consider this. I really hate port aggregation and was so happy when it was no longer needed in commercial installs. So many times the ports would get confused and strange stuff happen. One side would run port aggregation and the other wouldn't but since it though it was to be aggregated spanning tree was off. You would randomly get massive network loops that would crash whole buildings.

.....Are you even sure that router support port aggregation does no good to buy a switch if the router does not.

I would see what happens if you were to plug 2 machines directly into the router and run speedtest on both at the same time. In theory both should show 1gbit rates. I strong suspect if this is like other GPON installs that are similar the cable company is not telling the whole story. Many times they including the speed used by cable tv on the same fiber in their rates. They are quoting the rate of the fiber media not the rate they deliver. Hard to say some ISP are very dishonest.
Wow that is just shady. I knew they lied all the time about the packages prices and bandwidths but i never imagined they wouldnt provide the right hardware for that package... Well, the blames on me for not comnig to this topic before signing the 2 year contract and not after. Thank ypu for your help, this is probably the cause for the random connection losses!
 

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