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slickplaid

Slow Ramp Up on Download

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Does anyone have an explanation of what is going on with my speed tests? I've been noticing this lately that I have a high middle variance, and hitting my maximum speed takes a good 3-5 seconds, then it quickly drops back off after hitting it when it nears the end of the test.

 

Is this considered a "good" test?

 

qLVzp9X.png

 

Notice the "Middle" value is 100+mbps different from my final result, and the "maximum" speed is 180+mbps different.

 

My question is: What causes this and is there anything on my end I can do differently to correct it?

 

From TWC's own speed test:

QusVTYP.gif

 

Locally on my office network, transferring between nodes instantly hits a max speed (1gbps minus TCP latency overhead, before anyone suggests that I expect to receive that kind of speed or latency remotely on these tests, I understand this relationship well and don't need to be reminded).

 

Is there some sort of traffic shaping going on to slowly ramp up speeds on TWC's end or could there be something wrong on my end? Is it simply a router in my path to the source server seeing a longer connection and prioritizing it, outside of my control? Does anyone have good explanations for this if it's the norm? This even happens on TWC's own speed test, as it slowly ramps up to ~200-250mbps speeds over about 10-15 seconds.

 

The drop off at the end is what is most interesting to me, although the slow "ramp up" to appreciable speeds is what I am affected by most. Smaller filesize downloads never even reach close to my max speed, I only hit them with the 200mb test file size. (ex. 100mb, 50mb, 25mb - Links to test results)

 

My local network path looks like this:

D-Link DGS-1024D 1gbps Switch

Ubiquity EdgeRouter Lite

Motorola SB6183

to Time Warner Cable 300/20 mpbs Cable Internet

 

Thoughts? Suggestions?

 

As far as I can tell my connection is good to TWC:

 

0QP94Hq.png

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Ahhh, the Motorola Surfboard SB6183. I recently had one... actually two of them, returned them in favor of an 8 channel modem because the numbers here don't lie. Consistently slow starts on that modem. The 8 channel SB6141 initiates quicker and reaches full speed quicker. TestMy.net results were very clear and totally steered me to better performance. More channels don't always equal more performance.

Read this topic that unfolded when this happened.

SB6141, still kickin' butt. Saved money AND I'm faster.

post-2-0-64006500-1439819435_thumb.png

post-2-0-78460700-1439819445_thumb.png

I suggest you hit up BestBuy and give it a try. Hopefully you're still within the return policy on the 16 channel modem. I recommend buying from BestBuy because of their return policy... no questions asked if you decide that it's not what you need. -- seriously, I just went through the same deal. I'm pretty sure you're experiencing the same idiosyncrasies that made me loose confidence in that modem. For what I do here, developing TMN, that kind of wildly unpredictable performance arch wasn't going to suit the job.

Let me know how it goes. :wink:

(btw, don't bother with extended warrantees, if it runs for a few days with no problem... chances are it will run for years that way. These are very reliable pieces of equipment... just don't cover the all important air vents or restrict the heat dissipation in any way. e.g. don't put it in a confined space or put anything on top of it or your router.)

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Excellent response, thank you! I will see about getting the 6141 to see if it fixes the issue and report back.

 

I've recently done a complete overhaul of my home office networking equipment because a Mikrotik router was giving me some huge problems (sub 10mbit speeds on 1gbps link negotiation) and just bought what I assumed was the best cable router available.

 

Everything has been much better, but as always I'm looking for "best" not just "better", which prompted this query. I almost wonder if this is by design given how it ramps back when nearing the end of the file. I'll have to test it with a high speed VPN or something to see if the same traffic shaping pattern emerges when it can't detect the start and end of a transfer.

 

Unfortuantely, I bought it on Amazon about 4 months ago, so I doubt any return method is viable for me at this point. I'll eat the cost ;)

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@CA3LE, in your experience, will the SB6141 work with the 300/20 speed of DOCSIS 3.0?

 

On Time Warner's site, the SB6141 is listed as being able to reach speeds "up to 100Mbps" (obviously from your post above, that isn't completely true). Would it be able to reach 300mbps download or should I look at some of the other rated 300mbps routers listed on their "approved list" of routers?

 

The following are their approved list of ~300mbps approved routers:

 

C6300 - $200

CM500-100NAS - $100

D3CM1604 - $100

 

 

OnV64hf.png

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Unfortuantely, I bought it on Amazon about 4 months ago, so I doubt any return method is viable for me at this point. I'll eat the cost :wink:

 

Don't eat the cost... sell it on Amazon.  Still worth more than the 6141, even used.  

 

The SB6141 has a theoretical max of 343 Mbps down, 131 Mbps up.  Even my old SB6121 (4 channel) did well over 100 Mbps, easy... but I seemed to max out around 130 Mbps (it's theoretical max is 172 Mbps).  

 

You might need a 16 channel modem to truly pull your full 300 Mbps but I think that the SB6141 is worth a shot.  I'd try it... just make sure you can return it after your experiment.  ... if you find it works better sell the other one online and you'll probably still break even after seller fees.   :wink:

 

Personally, even if I dropped 20+ Mbps off the top end, I'd rather have it initiate instantly.  It's worth more to me if I was able to pull a consistent 260-280 Mbps vs having over 300 with that slow ramp up that you're displaying.

 

If you try it out, after you try it out... please share your results here.  You may help others in your same situation.

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Everything has been much better, but as always I'm looking for "best" not just "better", which prompted this query. I almost wonder if this is by design given how it ramps back when nearing the end of the file. I'll have to test it with a high speed VPN or something to see if the same traffic shaping pattern emerges when it can't detect the start and end of a transfer.

 

Unfortuantely, I bought it on Amazon about 4 months ago, so I doubt any return method is viable for me at this point. I'll eat the cost :wink:

 

First, I think that we're very similar consumers.  I too am always looking for the best technology available (in everything) and I thought that the latest Motorola modem would do what ever other previous generation did.  But it didn't.  I had to pull it back a little to get better performance.  Maybe it's the cable systems right now... maybe it shows what they're moving towards.  -- hope not, that would suck.

 

If you (or anyone else) happen to find a 16 channel modem (or better) that out performs the 8 channel SB6141 I'd love to know about it.  The two 6183's I tried both had the same curve that yours displayed.  Motorola in my mind has the absolute best cable modems.  Would be interesting to see a contesting brand with 16 channels or more that showed a definite performance gain in these tests.

 

I'd almost bet money that you'll have improved performance with the 8 channel modem.  We'll see soon.   :wink:

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So I've ordered the SB6141 and spoke with Time Warner about it after doing so.

 

They've told me that when I switch to the SB6141, their system will not allow me to use the 300/20mbps "Ultimate" speed provisioning and I will be reverted down to the old 100/10mbps speeds and they will not be allowed to modify that to use the theoretical 300+mbps speed rated on the packaging. Something to do about network saturation and the amount of bonded channels (8 down instead of the needed 16). The guy was pretty nice and he seemed to know what he was talking about (3rd person I spoke to, I assume he was a higher level tech support than the norm).

 

So, with that information, I've also purchased the CM500-100NAS, which despite it's product ID, does not contain a NAS controller or do anything but route those sweet packets down the cable.

 

Once I receive the SB6141, I will hook it up and test what the person I spoke to said, and see what kind of speeds I get. If it does indeed bump me back down to 100/10, I'll switch it back until I receive the CM500-100NAS to test it as well.

 

I'll report back when I have some of my findings once the mail gets delivered.

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So I've ordered the SB6141 and spoke with Time Warner about it after doing so.

 

They've told me that when I switch to the SB6141, their system will not allow me to use the 300/20mbps "Ultimate" speed provisioning and I will be reverted down to the old 100/10mbps speeds and they will not be allowed to modify that to use the theoretical 300+mbps speed rated on the packaging. Something to do about network saturation and the amount of bonded channels (8 down instead of the needed 16). The guy was pretty nice and he seemed to know what he was talking about (3rd person I spoke to, I assume he was a higher level tech support than the norm).

 

So, with that information, I've also purchased the CM500-100NAS, which despite it's product ID, does not contain a NAS controller or do anything but route those sweet packets down the cable.

 

Once I receive the SB6141, I will hook it up and test what the person I spoke to said, and see what kind of speeds I get. If it does indeed bump me back down to 100/10, I'll switch it back until I receive the CM500-100NAS to test it as well.

 

I'll report back when I have some of my findings once the mail gets delivered.

 

Well, that would suck if they do that.  They may train their reps to downgrade your account if you're not using the exact modems they want you to.  Lame.

 

Let us know how it goes.  I'd love to know that there was something better out there or a solution for the weak performance I've seen from 16 channels.

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Alright, so this has been pretty eye opening ordeal.

 

Just to recap: Ordered two routers to test. SB6141 and CM500-100NAS. I currently had the SB6183.

 

 

SB6183

 

Old test with SB6183 for comparison:

 

JpkQTrY.gif

eUvpsna.gif

 

SB6141

 

Now, I had them activate the SB6141. I didn't say anything about the type of router or anything, they just asked for the MAC address and it was activated 2-3 minutes later. Here are the results:

 

Kb3vdxO.gif

DJF1D9V.gifcpgLdLZ.gif

 

I asked them about it downgrading me, and the lady had no idea what I was talking about. She said my plan was correct and that router "just can't do the speed you have available". I didn't press any further because I'm sure what the outcome would have been unless I could trick one of them to accidentally enable the speeds it wasn't "rated" for in their system.

 

CM500-100NAS

 

I had them activate the new router and my first result was this:

 

p4vfUmX.gif

dauqQ2s.gif

Nice! That's what I'm talking about. The lady said she had to do a few more things to my account to clean up, so she put me on hold again. I ran a few more speed tests after a minute or two:

 

eUvpsna.gif

PMeYLgL.gif

pivPtLm.gifWat. I asked her if she did anything and she said she was just doing some clean up operations of my account and tested my connection one more time. What the heck? Almost identical now to what the SB6183 was doing before.

 

Long story short: Stayed on the phone for several hours tweaking things, even got a few other support members on the phone. All said everything looked good. Never got back to those initial results. They are sending someone out to look at the actual lines and diagnose it from my end Friday. I'll report back with more findings then.

 

Anyone have any thoughts to how that could have happened?

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I read this right when you posted it... realized just now I hadn't replied.

 

So when you got the killer speed it sounds like you were still on the phone with them.  Then, when she was 'finished' setting things up the speed dropped into that gradual curve pattern again.  Sounds to me like something is done on their end to make it curve like that.  I really hope that's not the direction things are moving in the industry.

 

I find it funny that they make the SB6141 top out at 100 Mbps.  It's far more capable.  My guess is that whatever they're implementing to cause it to ramp up so slowly can only be done on those 16 channel modems.  So, because the SB6141 is more capable... and would sully their plans... they won't allow it to be used with the top tier service.  Their network admins may have only allowed the modems they want.

 

I feel lucky now that Comcast isn't doing that to me... I'm not on a 300 Mbps plan like you are either...

 

post-2-0-00222300-1440486914_thumb.png

http://testmy.net/db/mNDz2o3u

 

That's an SB6141 on 150 Mbps Comcast, as you can see, there's no reason they need to limit that modem to the 100 Mbps plan.  It should be able to do near 300 Mbps too (theoretically higher)... and if it doesn't reach that absolute full speed then you as a customer should be able to make the choice whether or not to use it.  Not be forced to use a modem that obviously is made to perform to their overall network's favor. (not yours)

 

300 Mbps sounds better when you don't know the fact that it takes 3 seconds to ramp up to it's potential.   :sad1:

 

Watch... they'll start moving more in this direction.  Then, long term, they'll want to charge us more for them to turn that BS off!    -- better get that Platinum Extreeeeme level!   :evil:

 

--- btw the 'like' on your post... I like that you responded in such detail.  Not that you're still in the same boat. :wink: -- this topic will definitely help some people with questions.

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