[QOS] Question Regarding Bandwith and QOS Effectiveness

[AntonK]

Hi Networkers,

At what rate of download speed does QOS become helpful? I know, people usually respond to this by posing a question to the question, along the lines of "depends on your devices, quantity, and what they're doing."

But how about a determination based on your average family household, with say 7-10 wired and wireless devices, doing the usual things people do nowadays. At what download bandwidth (50mbs, 100mbs, 150mbs, 200mbs, etc.) should QOS be turned on? Adaptive QOS?

Thanks,
Anton

 

[dave14305]

I think the more likely your ISP connection is to get saturated, the more likely you want QoS. I would turn your question around to ask at what increasing level of bandwidth might you turn it off? Certainly if your router cannot reach your provisioned speed due to some levels of NAT acceleration being disabled (on Asus routers), then you might consider disabling it.

I’m interested to hear others opinions and experiences.

 

[AntonK]

Don't take this wrong, but that's the usual gibberish, and not generally helpful.

What I tried to communicate was, at what download speed (50,100,150,200...) do you active QOS on your router as a baseline, and work from there...

Anton.

 

[ColinTaylor]

Just because it's not the answer you wanted to hear doesn't mean it isn't correct.

QoS is not about speed but contention. As such it's about deciding what to prioritise when the demand exceeds the available bandwidth.

 

[AntonK]

Just because it's not the answer you wanted to hear doesn't mean it isn't correct.

QoS is not about speed but contention. As such it's about deciding what to prioritise when the demand exceeds the available bandwidth.

Sorry, but I'm not buying it. I understand contention but, for most people, its a question of generalization(ie. at what download speed are most home network users likely to experience contention issues at a given download capablity/bandwidth)? Without tools or the ability to use them effectively (e.g. bandwidth saturation readings, ets...) what good is your recommendation?

The broad-brush point is: at what bandwidth/download mbps account should people be looking at QOS as a likely (not necessarily) valuable tool.

Too often we see remarks on these forums like, "... with that download speed, you don't need QOS!" Really, than be more specific than that.

Anton

 

[ColinTaylor]

Well I don't know what the "average family household" is, or what constitutes "doing the usual things". But let's say your ISP download speed is 10Mbps, that's just enough for two people to concurrently stream Netflix in HD. Now a third person starts using Netflix. What might happen is that they all start getting a bad experience. Fortunately Netflix is clever enough to adjust the stream from HD to SD so that everyone can watch without problems.

Now let's say your ISP download is 500Mbps. Little Johnny is sitting in his bedroom torrenting his warez collection and saturating your download and upload bandwidth. Dad tries watching Netflix in the lounge but it's very poor quality and keeps buffering. Mum tries you use VOIP but can't even make a connection. This is where QoS would be effective. Or just unplug Johnny's PC.

Whenever your upload or download bandwidth approaches saturation the need to prioritise traffic becomes more important. The higher your bandwidth capacity the less likely that is to happen, and when it does the period is usually shorter (because the thing that's hogging the bandwidth completes quicker).

 

[ColinTaylor]

Just wanted to add that it's important to think of the "contention issue" on a moment by moment, second by second basis. It's tempting to think of things like Netflix as continuously streaming data at a certain bitrate but that's not what they're doing. What happens is that they download a chunk of data at the maximum speed possible, buffer it and then pause for a short time. So the traffic is "bursty".

This generally works out well when there are many devices sharing the same connection as it's not really noticeable if you have to wait an extra 200ms for your web page to load because it happens to coincide with Netflix downloading its next chunk. However it can be a big problem with latency sensitive applications like VOIP. With VOIP it's not acceptable to have its traffic repeatedly interrupted for 200ms because someone is watching Netflix. In this scenario QoS is almost essential regardless of how much bandwidth you have.

 

[CaptainSTX]

Based on my 170/12 connection from Comcast I think there is plenty of room for a Netflix stream and a VOIP call.

According to Neflix's fast.com speedtest they rate my connection at 160 Mbps with a 4 K Netflix video stream running when I did the test. While as you can see from the attached screen shot the average useage over ten minutes is only 20.2 Mbps. I don't see that QOS is necessary with my connection and I use a a T-Mobil micro cell for all connections when I am home.

The data screen shots are attached.

 

[RMerlin]

It's a matter of usage really. People generally say that QoS isn't really necessary with 1 Gbps links because it's very unusual for someone to actually saturate such a fast connection. Even torrenting tends to be slower than that because the torrent client often can't keep up with these rates.

If you do have multiple persons constantly saturating that link with multiple connections, then QoS might be necessary. But if you have, for example, one single person downloading a large file, it generally won't saturate the link - and if it does, packets would travel fast enough for a time-sensitive connection (like a Netflix stream) to still be able to mix with that large download with no visible impact.

 

[AntonK]

Great information and explanations. Very helpful to a relatively non-techie.

Anton

 

[Nullity]

Sorry, but I'm not buying it. I understand contention but, for most people, its a question of generalization(ie. at what download speed are most home network users likely to experience contention issues at a given download capablity/bandwidth)? Without tools or the ability to use them effectively (e.g. bandwidth saturation readings, ets...) what good is your recommendation?

The broad-brush point is: at what bandwidth/download mbps account should people be looking at QOS as a likely (not necessarily) valuable tool.

Too often we see remarks on these forums like, "... with that download speed, you don't need QOS!" Really, than be more specific than that.

Anton

There is no simple answer.

Your network, regardless of speed, is either idle or sending a packet. Whether your buffers (upload) or your ISP's buffers (download) are "too" saturated is up to you to decide.


Example: A video stream uses 20mbps of your 100mbps connection, which mean you have 80mbps free... No. Like I said, your connection is either idle or sending a packet (and therefore buffering any packets arriving before the current packet has been sent).

Does this 20mbps stream completely saturate your connection for 20 seconds out of every 100 seconds or does it it only saturate the connection for 20 milliseconds out of every 100 milliseconds? Or, more likely, does it fluctuate somewhat randomly?


Personally, QoS/traffic-shaping/fair-queueing/etc decrease my bandwidth by only a few percent while giving me much more consistent experience across many metrics, so I use it.

 

[CaptainSTX]

After reading this thread I thought I would enable adaptive QOS to see the impact on my connection. Entered my bandwidth and ordered the catergories. My service from Comcast is provisioned at 180/12. I am running the lastest version of Merlin on an AC1900P. VPN tunnel is run on a VPN appliance. Speed tests were run on DSL reports.

1. Test 1 VPN tunnel on no QOS = 169/12 Buffer Bloat Grade C
2. Test 2 VPN tunnel on Adaptive QOS with bandwidth for QOS set at 165/11 = 109/10 Buffer Bloat Grade C
3. Test 3 VPN tunnel off QOS off = 180/13 Buffer Bloat Grade C
4. Test 4 VPN tunnel on QOS off = 171/12 Buffer Bloat Grade C

I am sure if I had spent more time tweaking QOS settings I might have gotten higher download speeds but in my situation with just two adults in the household, I think I would be hard pressed to see any benefit from running QOS. All my homes network WAN traffic except for streaming devices is run through the VPN tunnel which may impact the effectiveness of QOS. Currently without using QOS all my primary streaming devices are hardwired and even with two 4K streams running I never encounter buffering with Netflix or Amazon and only occasionally with YouTube. All my cell traffic is routed over the Internet using a T-Mobil micro cell and I never any issues with call quality even with active streaming sessions running concurrently.

IMHO the usefulness for QOS becomes marginal long before you install a one gig connection for most people or families. I'm sure a case can be made for using QOS if you have a large family with many streamers, serious gamers or situations where someone is constantly uploading large files etc. but QOS is not needed for lots of people unless you have a slow connection. I think Comcast's lowest speed connection in most areas is 75 Mbps and ccording to Speedtest in the Q2-Q3 of 2018 the average download speed on a hardline connection in the USA was 95.24 Mbps. (Yes I know averages are misleading and the USA is only a small part of the world and I'm sorry if you live somewhere and have to depend on a slow DSL connection. )


http://www.speedtest.net/reports/united-states/

 

[ColinTaylor]

@CaptainSTX Thanks for the info.

All of the traffic going through your VPN would have all been put in one category. Even without the VPN active the same situation would have happened (it's the same type of traffic). As such the main benefit of QoS (prioritising different types of traffic) wouldn't have occurred. So in effect the only thing QoS was doing was acting as a bandwidth limiter.

But as you point out, unless people have quite high demands vs. their bandwidth capacity it's probably a moot point.

 

[coxhaus]

We have 2 people in my household with about 10 devices. With 200 Mbps connection there is no reason to use QOS. I don't even turn it on because usually there is overhead associated using QOS. I have to state we are cable cutters and have been for years so we stream Hulu, Netflix, Amazon Prime, HBO and few others from time to time.

I guess you know QOS is for when you saturate your internet pipe or it really makes no difference until you do. It does add overhead to your router all time. So it is somewhat of a trade off using QOS.

In the past I had 300 Mbps upgraded to 400 Mbps. I down graded because with Spectrum the response time or latency is the same. In the old days with Time Warner I got lower latency with the higher connection rate so I prefer lower latency and used the higher connection rate.

 

[AntonK]

We have 2 people in my household with about 10 devices. With 200 Mbps connection there is no reason to use QOS. I don't even turn it on because usually there is overhead associated using QOS. I have to state we are cable cutters and have been for years so we stream Hulu, Netflix, Amazon Prime, HBO and few others from time to time.

I guess you know QOS is for when you saturate your internet pipe or it really makes no difference until you do. It does add overhead to your router all time. So it is somewhat of a trade off using QOS.

In the past I had 300 Mbps upgraded to 400 Mbps. I down graded because with Spectrum the response time or latency is the same. In the old days with Time Warner I got lower latency with the higher connection rate so I prefer lower latency and used the higher connection rate.

Hi Coxhaus,

Please excuse me if this is a silly question, but when you say you are cable cutters, do you mean you're getting your internet feed from some technology other than cable? I've currently got something called Triple-Play from our cable company, where we get our landline service, basic cable, and internet from our cable company (Optimum.net). But, we don't need our landline, and we don't watch cable tv. We'd love to dump those 2 services and just stick with our outstanding 200/35 cable internet. But I've heard they've priced things so you really don't save that much.

Any thoughts?
Anton

 

[coxhaus]

Hi Coxhaus,

Please excuse me if this is a silly question, but when you say you are cable cutters, do you mean you're getting your internet feed from some technology other than cable? I've currently got something called Triple-Play from our cable company, where we get our landline service, basic cable, and internet from our cable company (Optimum.net). But, we don't need our landline, and we don't watch cable tv. We'd love to dump those 2 services and just stick with our outstanding 200/35 cable internet. But I've heard they've priced things so you really don't save that much.

Any thoughts?
Anton

No, I use cable for internet only no TV. I dropped my DirectTV many years ago. I stream all TV and movies except for local channels which I have an antenna in the attic. Cable TV is expensive if get any of the premium channels. I am not interested in their basic plan. Their phone price has gone up a lot also. I have had it all in the past.