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[Vanburen]

I have a Billion 7800DXL, which has 3300ms of bufferbloat when uploading on an ADSL2+ connection (888 kbps upload).

Given that the BiIlion Bipac 8800NL is quite popular here, I was wondering if anyone had experienced anything similar when using ADLS2+ on the 8800NL? Or wherever this is just a 7800DXL issue.

What is Bufferbloat?:
Basically Bufferbloat happens when a router buffers traffic, using a basic first in first out queue. As RAM has got cheaper, buffers in routers have got bigger. This means packets can be caught in the buffer long periods of time. This can destroy the performance of interactive performance of your internet connection, as it means that time sensitive packets like TCP acks can be held up for a long time. for much more info and better descriptions than I can manage, please see the below links:
http://www.bufferbloat.net/projects/bloat/wiki/Introduction

https://www.youtube.com/watch?v=quAaZKBHvs8

https://www.youtube.com/watch?v=y5KPryOHwk8

How do I test for Bufferbloat?
You can use the ICSI Netalyzer: http://netalyzr.icsi.berkeley.edu/

Look out for the uplink buffering section of the report, that should give you an estimate of the upload buffering. However bear in mind that the netalyzer tool has to be able to fill your upload buffer, which is quite easy on my 888 kbps upload, however I don't think it can fill the upload buffer on lines with much larger upload speeds (e.g. FTTC lines).

I have posted on the Billion forums:
http://www.billion.uk.com/forum/viewtopic.php?f=18&t=3509

But haven't heard any experiences from other billion users yet.

*18:40 (16-3-15): Edited to add extra bufferbloat video

[Chrysalis]

you have QoS or prioritisation functions enabled on the device?

[Vanburen]

you have QoS or prioritisation functions enabled on the device?

I haven't, mainly because Dropbox (which uses most of my bandwidth) uses port 80 and 443, so I would need to get a definitive list of Dropbox IPs to ensure I didn't shape my browser traffic.

Ideally, I don't want to have to use QOS, as it can be pain to setup, and even then it won't cover every edge case. A more ideal solution in the case of Bufferbloat, would be to use a better algorithm to manage the upload buffer. Specifically FQ_Codel has been created for this purpose. With FQ_Codel on the Billion, it would allow Dropbox to upload as fast as it could, but still let time sensitive packets like TCP acks get through in a timely manner. 

I'm hoping Billion can be convinced to enable FQ_Codel in their firmware 

[Chrysalis]

I asked as QoS would cause bufferbloat, so I have no explanation why you got the problem.

[richb-hanover]

If you're reading this forum, you might also be interested in the Quick Test for Bufferbloat at:

http://www.bufferbloat.net/projects/cerowrt/wiki/Quick_Test_for_Bufferbloat

As described there, you measure ping times, and then start a speed test. If the ping times increase during the test, then your router is not serving you well because it's buffering more data than can be sent (or received) at the time.

The other posters are correct that the fq_codel, PIE, or other smart queue management algorithms are well known and well tested techniques for solving bufferbloat.

[Tedworthy]

Just thought I'd add my experience here, given that I have a Billion Bipac 8800NL and saw your post both on this forum and Billion's.

I have noticed very similar behaviour on my router - like you I have a fairly marginal ADSL line so Billion routers are a very good option with their target SNR margin tweaks, which are invaluable to stop my exchange giving me stupidly high SNR margins and throttling the sync as a result. I've managed to take our download speed from around 1.8 meg actual to around 2.8 meg actual, with no noticeable instability or dropouts.

However the connection isn't perfect - I've always noticed latency going out the window when large uploads are occurring (Dropbox, iCloud Backups/Photos, etc.), which is a huge problem when trying to use Skype at the same time. At the moment I'm using a global upload limit QoS rule to limit each network client to 70% of the upload bandwidth, and a QoS prioritising rule matching traffic that vaguely looks like Skype on certain PCs.

Upon running the ICSI test I can also confirm similar results - 2800ms uplink buffering.

Whilst I have QoS turned on normally, as mentioned, I have since run the test both with my QoS rules active and with all QoS rules disabled, and the results are virtually identical - around 3 seconds of uplink buffering, hence bufferbloat.

I'm really hoping for some sort of solution from Billion on this, it sounds like fq_codel is an excellent alternative algorithm and there has clearly been lots of work done by kind people independent from router manufacturers to investigate and solve bufferbloat. Why OEMs can't integrate this into their respective firmwares is beyond me. If a massive security issue suddenly became public that affected router firmwares, surely they would try to rush out a fix to all the affected devices? I appreciate bufferbloat is not quite in the same level of urgency but it seems like a relatively simple fix to implement to give certain users a vastly improved experience.