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NetFixer
From My Cold Dead Hands
Premium Member
join:2004-06-24
The Boro
Netgear CM500
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TRENDnet TEW-829DRU

1 edit

NetFixer to JohnInSJ

Premium Member

to JohnInSJ

Re: [Speed] Comcast Business Class Speed Upgraded in California

said by JohnInSJ:

rebooted this morning in san jose
12/2 is now

Upstream: No shaper detected.
Median received rate: 3397 Kbps.

Downstream: Burst size: 9843-9962 KB; Shaping rate: 17024 Kbps.

17/3 - nice.

Not sure why it didn't see a speedboost on the uplink.

I randomly see no PowerBoost reported on both the upstream and the downstream when testing with ShaperProbe.

But I would actually like to see Comcast offer a config option to disable PowerBoost anyway. In fact, I usually run through a VLAN segment of my Netgear GS108e switch just behind my cable modem so that I can use its rate limiting QoS capability to compensate for the sometimes extreme buffer bloat effect that the combination of Comcast's PowerBoost and channel bonding sometimes exacerbate. Since the "leak" of Comcast's plan to increase the bandwidth for the two lower business class tiers, I have removed that VLAN connection until I could verify exactly what the new speed tier delivered. Now that I know, I will probably put that rate limiting VLAN segment back into operation.

EDIT:
I just put my rate limiting VLAN segment back into service, and I thought I would post some ICSI Netalyzr results to illustrate why I did it:


Netalyzr results without rate limiting


The 690 ms upstream buffer value above is actually an improvement over the ~1000 ms value I was seeing prior to the rate increase from 2mbps to 3mbps (which makes sense because the improved excess buffering ratio tracks the real bandwidth increase ratio).


Netalyzr results with rate limiting


Here is a link to an ICSI FAQ that explains the effects of excessive buffering (AKA buffer bloat): »n3.netalyzr.icsi.berkele ··· fer.html

Here is a brief extract from that FAQ:
said by ICSI :
Often, your computer wants to send or receive data faster than some point in the network allows. Thus that point needs a buffer to store this data until it is able to send it. The problem arises when the buffer is too large or too small. If the buffer is too small, network protocols such as TCP are unable to send as fast as the network allows. If the buffer is too large, a single transfer will fill up the buffer, delaying all other traffic.

Currently, a lot of users have networks which are significantly over-buffered. As a result, if the network is running at capacity, packets may be substantially delayed. This is why, for example, BitTorrent may slow down a user's web surfing, even though TCP is able to share all the bandwidth, the file transfer fills up the buffer which now slows down all other traffic.

In other words, those of you who are bemoaning an apparent loss of PowerBoost with the new speed increase, might want to be thankful instead of angry.

ropeguru
Premium Member
join:2001-01-25
Mechanicsville, VA

ropeguru to pflog

Premium Member

to pflog
said by pflog:

Definitely looks like I've lost power boost on the upstream side, and either all or most of it on the downstream side.

Exactly what I am seeing here.

But as someone else was saying. Just deal with it! J/K

NetFixer
From My Cold Dead Hands
Premium Member
join:2004-06-24
The Boro
Netgear CM500
Pace 5268AC
TRENDnet TEW-829DRU

NetFixer

Premium Member

said by ropeguru:

said by pflog:

Definitely looks like I've lost power boost on the upstream side, and either all or most of it on the downstream side.

Exactly what I am seeing here.

But as someone else was saying. Just deal with it! J/K

Or perhaps even be happy about the reduced PowerBoost?

Some of us actually go to the trouble to limit the negative effects of PowerBoost:
»Re: [Speed] Comcast Business Class Speed Upgraded in California

Of course, the universal YMMV disclaimer is always in effect.

pflog
Bueller? Bueller?
MVM
join:2001-09-01
El Dorado Hills, CA

pflog

MVM

I can understand folks being upset about losing something they had for a long time, especially if their rep told them to expect it.

That said, I for one would much rather have sustained 27/7 with no PB and have it shaped properly, which lets me control things much more on my end via shaping/QoS.

Anyone know of a good consistent host to wget/fetch a file from in California (at least 256 MB) so I can do a pcap capture and see how the throughput graph looks for sustained transfers?

JigglyWiggly
join:2009-07-12
Pleasanton, CA

JigglyWiggly

Member

powerboost on buisness is really nice.
Like if you host a bunch of images, it will load faster with the high upload rate for the short period. Especially if those pictures are like 8 megabytes.

JohnInSJ
Premium Member
join:2003-09-22
Aptos, CA

JohnInSJ

Premium Member

Likely it will return. Just give it a few days for them to get the kinks out.

ropeguru
Premium Member
join:2001-01-25
Mechanicsville, VA

ropeguru to pflog

Premium Member

to pflog
said by pflog:

I can understand folks being upset about losing something they had for a long time, especially if their rep told them to expect it.

That said, I for one would much rather have sustained 27/7 with no PB and have it shaped properly, which lets me control things much more on my end via shaping/QoS.

Anyone know of a good consistent host to wget/fetch a file from in California (at least 256 MB) so I can do a pcap capture and see how the throughput graph looks for sustained transfers?

Look around at some of the linux mirrors where you can download the DVD. THat will give you a good 4GB worth of data to test with.

I am getting ready for work now but if I have a little time when I get there, I will take a quick look and see if I can find on for ya.

pflog
Bueller? Bueller?
MVM
join:2001-09-01
El Dorado Hills, CA

pflog to greg925

MVM

to greg925
Click for full size
Picked a local FreeBSD mirror to fetch a large file from, and the speeds start out relatively smoothly shaped. But then the shaping becomes less smooth and it bounces around between slow and fast rather erratically.

Anyone else in California on a 22/5 (now 27/7?) plan who can do a pcap and generate similar data to see if the shaping is broken in other locations as well?

SpaethCo
Digital Plumber
MVM
join:2001-04-21
Minneapolis, MN

SpaethCo

MVM

said by pflog:

Anyone else in California on a 22/5 (now 27/7?) plan who can do a pcap and generate similar data to see if the shaping is broken in other locations as well?

I don't have the data to post right now, but yes, I'm observing the same behavior in the Minneapolis market.

pflog
Bueller? Bueller?
MVM
join:2001-09-01
El Dorado Hills, CA

pflog

MVM

said by SpaethCo:

said by pflog:

Anyone else in California on a 22/5 (now 27/7?) plan who can do a pcap and generate similar data to see if the shaping is broken in other locations as well?

I don't have the data to post right now, but yes, I'm observing the same behavior in the Minneapolis market.

Ok, cool. I was starting to worry it was my TCP stack, but I've fiddled with a number of things including different congestion control algorithms, etc and am seeing similar results and the fact that it's relatively smooth in the beginning then erratic after the point where powerboost would normally cease tells me it is something on Comcast's end.

I'm guessing they are just ironing out the kinks in the buffering/etc with the new speed profiles?

JohnInSJ
Premium Member
join:2003-09-22
Aptos, CA

JohnInSJ

Premium Member

said by pflog:

I'm guessing they are just ironing out the kinks in the buffering/etc with the new speed profiles?

Seems like it to me, too, on whatever 12/2 is now I saw a brief moment of speedboost on the uplink this morning. Once. Weird.

SpaethCo
Digital Plumber
MVM
join:2001-04-21
Minneapolis, MN

SpaethCo to pflog

MVM

to pflog
Yeah, after seeing that behavior I ended up using tc to smooth the traffic myself using hierarchical token buckets on my Linux NAT box.

What I'm doing is loosely based on this: »www.iplocation.net/tools ··· trol.php

I've had favorable results shaping to 30,000,000 bps so far.
ualdayan
join:2004-07-17
Antioch, TN

ualdayan

Member

From my latest bill, the name of my plan changed to: "Ultra Internet 22Mbps with Powerboost speeds up to 30Mbps". I just upgraded from the 12Mbps to the 22Mbps this month, so can anybody else say if that was always there or not on their bill too?

ropeguru
Premium Member
join:2001-01-25
Mechanicsville, VA

1 edit

ropeguru

Premium Member

Here is what is on mine:

Internet Premium Pkg 10/05 - 11/04 99.95
Business Class Internet

Here is what it was:

Ultra Internet Service 09/05 - 10/04 99.95

To add that my July bill had this:

Ultra Internet Service 08/05 - 09/04 99.95
Includes PowerBoost

So they have taken away powerboost without notifying us business customers and changed the package name TWICE! Would be nice if one of the folks from Corporate would chime in and tell us what is going on.

Guess it is time to call my rep and hammer on him.

EDIT: Added July bill and changed some wording
biomesh
Premium Member
join:2006-07-08
Tomball, TX

biomesh

Premium Member

The speeds at »business.comcast.com/smb ··· et/plans have been updated, but the prices have not increased.

I hope this just means the speeds were increased and not the prices going forward.

ropeguru
Premium Member
join:2001-01-25
Mechanicsville, VA

ropeguru

Premium Member

said by biomesh:

The speeds at »business.comcast.com/smb ··· et/plans have been updated, but the prices have not increased.

I hope this just means the speeds were increased and not the prices going forward.

I just got a response back from my rep that assured me that the PowerBoost speeds I used to see have not been removed for my market. He advised me to contact customer care, and I will, to check on the issue. I also advised him that if the terms had changed, I would possibly be looking to cease the current contract with no ETF.

NetFixer
From My Cold Dead Hands
Premium Member
join:2004-06-24
The Boro
Netgear CM500
Pace 5268AC
TRENDnet TEW-829DRU

NetFixer

Premium Member

said by ropeguru:

said by biomesh:

The speeds at »business.comcast.com/smb ··· et/plans have been updated, but the prices have not increased.

I hope this just means the speeds were increased and not the prices going forward.

I just got a response back from my rep that assured me that the PowerBoost speeds I used to see have not been removed for my market. He advised me to contact customer care, and I will, to check on the issue. I also advised him that if the terms had changed, I would possibly be looking to cease the current contract with no ETF.

Wow, you actually have a sales rep who returns your calls/emails? I have not been able to get any kind of reply from my "official" sales rep since the day that I signed the contract.

Anything I have needed since that day, I have had to just make multiple calls to support, or use the »Comcast Direct forum (or just post here and hope that someone from Comcast would see the thread).

ropeguru
Premium Member
join:2001-01-25
Mechanicsville, VA

ropeguru

Premium Member

Guess I should feel lucky. I have also posted in the Direct forum and ComcastSteve just replied. However, what he replied with really didn't make much sense. So I am awaiting further clarification.

pflog
Bueller? Bueller?
MVM
join:2001-09-01
El Dorado Hills, CA

pflog to greg925

MVM

to greg925
I actually wouldn't be that upset about losing power boost, as I kind of prefer a consistent, stable connection. However:

- with these speed changes, the downloads are now erratic as I and others have pointed out. Hopefully this is just a hiccup and not permanent.

- lack of notification of the change is rather troubling, especially for people like ropeguru See Profile who was told by their rep they had it. I don't recall whether I was told about it or not, but if I had been and it suddenly went away, that would concern me as a breech of contract.

I would be thrilled with 27/7 if it were consistent. So hopefully they will fix the erratic throughput issue with their shaping settings. But for those that rely on powerboost, hopefully you get it back.

I will say it again: I wish there was a way to opt out of powerboost. It would make doing my own traffic management much easier.

ropeguru
Premium Member
join:2001-01-25
Mechanicsville, VA

ropeguru

Premium Member

said by pflog:

- lack of notification of the change is rather troubling, especially for people like ropeguru See Profile who was told by their rep they had it. I don't recall whether I was told about it or not, but if I had been and it suddenly went away, that would concern me as a breech of contract.

While loss of powerboost is something I am upset about, I am more upset that we pay higher rates for business level service and there is absolutely NO communication that changes are coming or have even taken place which effect our service.

I will say that since I have had Comcast business class service, going on three plus years now, the ONLY communication I have received from them was the note in my bill about the modem rental fee and sales crap. Nothing else.

pflog
Bueller? Bueller?
MVM
join:2001-09-01
El Dorado Hills, CA

pflog

MVM

Yeah, I called support (because apparently I can't login to businessclass.comcast.net, nor could I create an account, yet comcast.com had worked for years to see my bill). Anyway, while I was talking to the rep, I mentioned the 27/7 and loss of speed boost and erratic download speeds after the first ~30 seconds (coincidentally about when PB would have ended) and she told me my modem stats were bad (look fine on my end) and had no knowledge of this 27/7 plan.

Typical large corporation with the left hand not talking to the right.
noisefloor
join:2010-05-09

noisefloor

Member

Pretty obvious the bin file burst settings are broken. Not I care, I'd rather not have it. »business.comcast.com/smb ··· et/plans is updated with the new speeds.
Tekneek
join:2012-02-19
Bethlehem, GA

Tekneek to greg925

Member

to greg925
Until we lost our connection for a short time last night, we were usually testing anywhere from 55 to 75 Mbps down. Since the small outage last night, it has maxed out at just over 35 Mbps down. We would also tend to test at 11 to 14 Mbps up, and it stops at just over 7 Mbps down now.

Is this likely the result of changes to the service that Comcast enacted this week? We were not given any notice of an outage or other change to the service, it just happened sometime between 10 PM and midnight last night (eastern). I have not called to discuss it yet, because I am waiting to see if the change creates a usage problem on our end before assuming it will.

pflog
Bueller? Bueller?
MVM
join:2001-09-01
El Dorado Hills, CA

pflog

MVM

Yes, it sounds like you had the same configuration/speed profile change happen.

The things that appear to have changed (not sure if these would affect you or not):

1. complete loss of powerboost on the upstream
2. complete or almost complete loss of powerboost on the downstream
3. download speeds are shaped properly for the first 30 seconds, but then become erratic afterwards. Overall speed is great (~3.4 MB/s for me), but the traffic is up and down, similar to what one would see with packet loss or a mis-configured shaper past the CPE.

Anyone else notice any other differences? Those were the big 3 I noticed.
crucialcolin11
join:2004-09-12
Roseville, CA

crucialcolin11 to greg925

Member

to greg925
interesting to see a speed increase coming to the business class side. There was a noticed Comcast outage about a week or so ago at our business location. also funny the upgrade happens right about the same time we just switched the connection from Comcast to Surewest now getting 18/18 mbps via fiber.

Unfortunately at home I don't have that option as our street doesn't have fiber installed. I'd be curious if this means speed upgrades might be coming shortly to res service(currently on blast 25/4). I've also been noticing outages here as well overnight lately during normal maintenance hours. Same thing happened last time before they added upstream channel bonding.
greg925
join:2010-12-23

greg925

Member

I just noticed today My speed is back to the old speed (22mbps) I hope it gets back to the new speed (27mbps) or I will call Comcast tomorrow.

Chester2
join:2000-10-17
Menlo Park, CA

Chester2

Member

said by greg925:

I just noticed today My speed is back to the old speed (22mbps) I hope it gets back to the new speed (27mbps) or I will call Comcast tomorrow.

My 12/2 connection went to 17/3 and then for the last 48 hours bounced around between 2/1 and 17/3. Tonight it is right back at 12/2.
greg925
join:2010-12-23

greg925

Member

I have just restarted my modem and router and still my speed is 22/5 which is definitely the old speeds. I wonder if anyone else is also experiencing this issue ?
noisefloor
join:2010-05-09

noisefloor to Chester2

Member

to Chester2
Try using a download manager (such as downthemall for FF) and download something 200MB in size like an Nvidia video driver. You might need multiple tcp connections per download to see your maxed rate. This way I get a continuous 2MB/s which equals 16Mb.

SpaethCo
Digital Plumber
MVM
join:2001-04-21
Minneapolis, MN

1 recommendation

SpaethCo to pflog

MVM

to pflog
said by pflog:

So hopefully they will fix the erratic throughput issue with their shaping settings.

It's pretty clear it's set to hard discard packets above the subscribed rate after the powerboost byte quantity has been satisfied. My guess is the profile probably has an option to police or shape, and this is policing instead.




Graph is packets per second in relation to time on a steady transfer from a well connected public mirror.

You can see TCP responds sharply to a surge of packet loss once the transmit rate threshold is crossed.