Charting Fibre speed over time.

[jacof]

Hi all.

My Fibre link speed is all over the place. I am with Openserve and used to be with MWEB on the ISP side but after they could not solve the problem I decided to move and also find a better deal. I went to WebAfrica as they had the best deal on Openserve. At first all worked fine. But now I get the same issues so I suspect that it is Telkom that is the problem. I have had Telkom here 2 time and they tested the fibre link and it shows all OK. but as soon as the drive off it starts again.

My speed will be 100 mb/s one moment and then drop down to 4 mb/s. It is not my network as I tested it with a broadband connection between a PC and the OTN and I see the same thing there. I also run a Mikrotic router where I can see all the links and when I do a speed test I can see that the PPPoE link will go to what ever I see on the speedtest side. So it is not another machine on my network hogging the line.

So now I want to graph my speed over time. I found http://testmy.net/ that will do it but they dont have local servers so I dont get the speeds they I get to a local server. I want to see when it is that my speed drops to see if I can find a pattern.

Thanks all.

 

[jacof]

Here you can see what happens.

https://www.youtube.com/watch?v=Rn9N85Zxlfw

 

[savage]

Does the speeds return to normal after a while, or MUST you disconnect / reconnect to get back to the normal speeds?

If the speeds come back by itself (without disconnecting / reconnecting), my money is going to be on congestion on the PON interface. Yes, PON networks is shared, once the port is over subscribed, your speeds will be affected by others on the same port - just like on DSL and "exchange" congestion.

 

[jacof]

I had a Openserve tech at my house this morning and he saw with his own eyes what was happening. They gave me a Telkom test account and then all was fine. They are going to monitor my port today and I will switch between the Telkom account and the
WebAfrica one. They will give me a report on the speed on that port. It seems that the ISP is not capable to handle the speed all the time.

What is interesting is that both MWEB and WebAfrica are on the IS backbone. Maybe that has somthing to do with it. Is it just me that is seeing this or do other also see their speed going up and down all the time ?

 

[PBCool]

Are you sure you don't have recursive DNS open on your tik? And so disconnecting and reconnecting changes your IP which resolves it temporarily?

EDIT yeah throughput does look all over the place. Would help if I finished the video.

 

[jacof]

So after testing with the Telkom test account it is clear to see that the problem is with WebAfrica and not with the Fibre. I have beet switching between the accounts and run the tests all the time and as you can see using the Telkom account the speed stays above 90 most of the time.

 

[cavedog]

The joys of a PON.

I noticed some slowdowns for me during peak time too. I have fibre from A360 and they like Openserve installed a PON fibre and it gets congested quickly especially if there is a lot of 100Mbps users on the network.

 

[jacof]

Hi. Sorry I just want to make sure I understand correctly. PON is the hardware side of the network. https://en.wikipedia.org/wiki/Passive_optical_network
So if it was the fiber link then I should see the same speed issue when on Telkom as well as it is using the same fibre link. But if I switch to the Telkom account all is fine. Or am I missing something on how the fibre works? The way I understand it is that the speed issue is on the IS backbone.

 

[willsotaku]

Hi. Sorry I just want to make sure I understand correctly. PON is the hardware side of the network. https://en.wikipedia.org/wiki/Passive_optical_network
So if it was the fiber link then I should see the same speed issue when on Telkom as well as it is using the same fibre link. But if I switch to the Telkom account all is fine. Or am I missing something on how the fibre works? The way I understand it is that the speed issue is on the IS backbone.

PON has limited bandwidth for all users as they install a few users on the same splitter so you share the 2.4GBps on that link (numbers might be wrong) but if you get better speed on another ISP then its throttling for sure i have no love for WebAfrica if during peak times when everyone is home and your speed is still good i would say its more throttling then congestion would take quite a few 100MBps users to max a PON splitter

 

[Kyoto]

PON has limited bandwidth for all users as they install a few users on the same splitter so you share the 2.4GBps on that link (numbers might be wrong) but if you get better speed on another ISP then its throttling for sure i have no love for WebAfrica if during peak times when everyone is home and your speed is still good i would say its more throttling then congestion would take quite a few 100MBps users to max a PON splitter

My understanding is that Telkom/openserve use a 32:1 split ratio, so if all 32 customers were maxing out the line they would get +-75Mbs, this does not take into account statistical multiplexing etc. Since the average speed sold in the SA is between 25 and 40meg, the PON ports are never (at this time) going to be congested. The biggest issue weather it is GPON or AE is the backhaul if that is not provisioned correctly you can get significant congestion.

 

[savage]

My understanding is that Telkom/openserve use a 32:1 split ratio, so if all 32 customers were maxing out the line they would get +-75Mbs, this does not take into account statistical multiplexing etc. Since the average speed sold in the SA is between 25 and 40meg, the PON ports are never (at this time) going to be congested. The biggest issue weather it is GPON or AE is the backhaul if that is not provisioned correctly you can get significant congestion.

Many, many, assumptions there. Telkom has a history of congestion and over selling, just look at ADSL. I do not for one second believe that Telkom won't oversell PON either. Neither do I for one second believe PON will never be congested either.

Yes, you can average this, average that. Fact of the matter is, as users get added, as speeds are bumped up, things WILL get congested. It will go the same route as "exchange congestion" and ADSL...

 

[Kyoto]

Many, many, assumptions there. Telkom has a history of congestion and over selling, just look at ADSL. I do not for one second believe that Telkom won't oversell PON either. Neither do I for one second believe PON will never be congested either.

Yes, you can average this, average that. Fact of the matter is, as users get added, as speeds are bumped up, things WILL get congested. It will go the same route as "exchange congestion" and ADSL...

I never said that, I said Telkom use 32:1 split which gives each customer +-75meg, and since at THIS point in TIME the average speed purchased is 25 to 40 meg, so congestion on a PON will be very unlikely, yes in future it may well be.

 

[cavedog]

My understanding is that Telkom/openserve use a 32:1 split ratio, so if all 32 customers were maxing out the line they would get +-75Mbs, this does not take into account statistical multiplexing etc. Since the average speed sold in the SA is between 25 and 40meg, the PON ports are never (at this time) going to be congested. The biggest issue weather it is GPON or AE is the backhaul if that is not provisioned correctly you can get significant congestion.

Well I did read that on a single OLT it splits like 4, 8, 16 and 32 making the total 64 users per OLT. So I'm not sure why you would think that Telkom won't max an OLT on 64 users and later install more OLTs as the congestion or uptake increases.

I stand to be corrected though but that is what I read.

 

[SpiderGear]

If you have a linux box you can probably run Speedtest-CLI on cron every X minutes/hours and output that to a webpage.

 

[mister]

If you have a linux box you can probably run Speedtest-CLI on cron every X minutes/hours and output that to a webpage.

You can do the same thing on winblows

 

[jacof]

OK I wrote some python code using the ookla speedtest API. I am now plotting the download and upload every 10 minutes.
I will let it run over the weekend and see what we get as we are going away so nobody will be using the link.

As for the PON link. I don't think that is the issue as when I use the Telkom test account everything is ok. I am using the same fibre link therefor if it was congestion on the link I should still see it even with the telkom account.

 

[Geoff.D]

Does the speeds return to normal after a while, or MUST you disconnect / reconnect to get back to the normal speeds?

If the speeds come back by itself (without disconnecting / reconnecting), my money is going to be on congestion on the PON interface. Yes, PON networks is shared, once the port is over subscribed, your speeds will be affected by others on the same port - just like on DSL and "exchange" congestion.

Unfortunately yes you are correct. The only time this will not happen is if the service provider deliberately ensures that a particular PON interface "never" exceeds the total data capability as "sold" to all those sharing it. In other words for example, IF the interface is a 1G interface, then 10 users can be connected to it, all getting 100 Mb/s each.

 

[Geoff.D]

OK I wrote some python code using the ookla speedtest API. I am now plotting the download and upload every 10 minutes.
I will let it run over the weekend and see what we get as we are going away so nobody will be using the link.

As for the PON link. I don't think that is the issue as when I use the Telkom test account everything is ok. I am using the same fibre link therefor if it was congestion on the link I should still see it even with the telkom account.

At this stage you are correct. It is rather difficult to imagine that any of the fibre providers have reached saturation on a PON. The problem is capacity related feeding that PON, which is more likely than not an oversell issue with your ISP. Any ISP, Telkom included, will always/should make sure their "test" accounts are "never" exposed to "congestion" at any point in the network.

I am sure we are going to see more of this and finally we will get to the point about where most issues of poor performance slow throughputs etc actually occur and maybe even get to the point where the "bad" reputation that ADSL has will finally be exposed for what it is -- Nothing more than gross overselling of capacity.

 

[jacof]

The Python code works very well. I first had it running on a Raspberry Pi. The download speed is fine but the SD card can not handle the upload so I moved the code to a Windows PC on my network.

Here you can see how it works.

[video=youtube;lr6m_6Tasck]https://www.youtube.com/watch?v=lr6m_6Tasck[/video]

Here are the EMON plots. and as you can see when I moved the code to the Windows PC the upload jumped to what it has to bee because the Pi cant hanle the upload on the SD card side.

Download and Ping



Upload.



I will check the avg speed now that the code is running on the Windows PC, But as far as I can see I will never get 100Mbps. Thus the question is why do the ISPs say its a 100Mbps line when in fact it is only a 90 or 86. I am paying for a 100 but dont get it. I am getting 14 Mbps less. The is more that 100% less that a 10Mbps line. Thus they should reduce the cost of the 100 Mbps line with the full cost of a 10 Mbps line.

How do the rest of you feel about the fact that you pay for 100 and only get 86 ?

 

[coop]

How do the rest of you feel about the fact that you pay for 100 and only get 86 ?

If I had that problem constantly, I would be annoyed. However, I'm lucky in that I'm with Vumatel for fiber and CISP for bandwidth, so I rarely see any speeds of less than 100Mb/s for local traffic. See http://www.speedtest.net/my-result/6514724920

I wouldn't expect to get those results for international traffic as a lot depends on the configuration of the remote server.

That said, there is a small overhead to running an internet connection, so I would be happy with slightly less than 100Mb/s. But going as low as 86Mb/s would make me feel aggrieved.