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I live on a campus in the US and I am trying to understand why my upload speed to the online backup service Backblaze on area Y of the campus is 10 times slower than on area X of the campus (20000 vs 2000 kpbs as you can see in the details below).

Area X on campus (Ethernet):

  • Backblaze speedtest: Download Speed: 48764 kbps (6095.5 KB/sec transfer rate); Upload Speed: 25035 kbps (3129.4 KB/sec transfer rate)
  • speedtest.net speed test: Download Speed: 82460 kbps; Upload Speed: 71640 kbps
  • Backblaze actual upload speed using the client: around 20000 kbps

Area Y on campus (Ethernet):

  • Backblaze speedtest: Download Speed: 50500 kbps (6312.5 KB/sec transfer rate); Upload Speed: 3249 kbps (406.1 KB/sec transfer rate)
  • speedtest.net speed test: Download Speed: 94790 kbps; Upload Speed: 50880 kbps
  • Backblaze actual upload speed using the client: around 2000 kbps

I have similar results for wifi but I think that's enough details.

The network administrator suspects that Backblaze is doing IP-based throttling. This surprised me as

  • the Ethernet's IP is pretty similar between area X and Y
  • the Wifi's IP is pretty similar between area X and Y
  • I don't see what Backblaze would target area Y and not Y, since both are on the same campus. Also Backblaze vehemently denies doing any IP-based throttling, and I couldn't find anyone complaining about it.

My feeling is that area Y "as well connected" as X to the outer Internet, but most of the web services work fine, which gives credit to my network administrator's explanation.

Hence my question: is there any way to detect whether an online backup service is doing IP-based throttling, beyond comparing the upload speed with different IPs?

EDIT: Some details:

  • all tests where carried out using the same laptop.
  • I disabled the throttling in the Backblaze client's options.
masegaloeh
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Franck Dernoncourt
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    You will almost certainly find the problem _on campus_. – Michael Hampton Apr 17 '14 at 21:24
  • There could be a number of factors on and off campus. Are the school's routers ports different speeds? How many people are on the school's routers? WiFi, are they the same technology? On my campus we are in the middle of an upgrade and have some N and some G routers. Was one of the tests done when internet connection on/off campus is at a peak? (if it one was done in the evening upstream providers may be bogged down). – Travis Pessetto Apr 17 '14 at 21:28
  • @TravisPessetto Wifi is N everywhere. Ethernet is 100 Mbps at area Y (due to floor switches; cables are 1 Gbps though), 1 Gbps at area X. The test where carried out at 30 minute interval, and I have seen this trend (X is 10 times faster than Y) for months, any day of the week, any hour of the day. – Franck Dernoncourt Apr 17 '14 at 21:32
  • @MichaelHampton Thanks, but more generically speaking, regardless of the fact that I am located on a campus, is there any way to detect whether an online backup service is doing IP-based throttling, beyond comparing the upload speed with different IPs? – Franck Dernoncourt Apr 17 '14 at 21:39
  • Another thought, say your internet connection does not guarantee the full 1 Gbps at anytime, which most ISPs don't. Your 1Gbps connection at X is the full dedicated connection and is running at full speed, but at area Y your switch has 10 computers attached and guarantees each of the computers on the switch an equal share of the full bandwidth, this in turn only gives you a fraction of what is available and seems to go along with being ten times slower. If you could remove a connection to a switch and go directly to the 1Gbps it may show different results. – Travis Pessetto Apr 17 '14 at 21:55
  • In that case how would it explain that in area Y the speedtest.net results are good while backbaze is slow? – Franck Dernoncourt Apr 17 '14 at 21:58
  • Why the downvote? (off-topicness is no reason to downvote) – Franck Dernoncourt Apr 17 '14 at 22:57
  • Actually my bad, off-topicness [is a reason to downvote](http://meta.serverfault.com/q/6266/126950) on this SE. So go ahead. – Franck Dernoncourt Apr 18 '14 at 03:43

1 Answers1

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"is there any way to detect whether an online backup service is doing IP-based throttling" -

Even though your question is Off-Topic for ServerFault, I'll help before a Meta post shows up.

Since you mention it is Backblaze, they provide a service URL to test your speed:

http://www.backblaze.com/speedtest/

And on that same page discuss how to check if throttling is enabled in the client or not.

It would appear from your tests that you've already been to that page, but that's about the best you are going to get.

If there is speed throttling occuring it is more likely at the firewall/router/LAN layers within area Y. So either the netadmin doesn't know or isn't being truthful about the setup.

TheCleaner
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  • Thanks. If my question is off-topic here, I'm fine if you migrate it to the right SE. I replied to your answer in the questions' details: all tests where carried out using the same laptop, and I disabled the throttling in the Backblaze client's options. – Franck Dernoncourt Apr 17 '14 at 21:37
  • I doubt the question will be migrated, just likely closed. You could consider asking again on SuperUser though. I think the final 2 sentences I posted though is your likely answer. You can go here: http://www.measurementlab.net/tests and try out their tests, but they may prove inconclusive in this instance. – TheCleaner Apr 17 '14 at 21:49
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    Pleased don't answer off topic questions it implicitly encourages them :( and stops the cleaning fairies from cleaning them up. – user9517 Apr 18 '14 at 05:26
  • @Iain - ok. I felt the question itself was on-topic even the OP wasn't. I figured the closed question would still linger and allow for searches of "detect bandwidth throttling" – TheCleaner Apr 18 '14 at 12:56
  • Frankly I didn't argue but I believe my question is on-topic and falls under "Network routing, switches, and firewalls". I am pretty sure that some of network admins would probably like to know a direct way to detect IP-based throttling (which is my one and only question, the rest being simply the motivation behind to avoid people asking why I want to do it, as I'm tired of this kind of comments). Also, I'm pretty far from being in a home or development environment: my network environment is the entire 18.0.0.0/8. – Franck Dernoncourt Apr 18 '14 at 15:35
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    @FranckDernoncourt: You're not the administrator of that network though, you're just an end user of it. You don't have any control or authority over the network. Server Fault is not here for end users of other people's networks it is here for the administrators of the networks. We regularly close end user questions as off topic for one reason or another. – user9517 Apr 19 '14 at 05:37