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fuziwuzi
Not born yesterday
Premium
join:2005-07-01
Atlanta, GA

1 edit

Is the Comcast Congestion Management System Throttling?

Split from this topic --> »Data Usage Meter Launched
~sorto'


said by netcool:

The difference is that the usage is now updated every 3 hours whereas before Usage was only looked at once a month by the customer service assurance team.

Getting 3000+ CMTS devices (that include Motorola, Cisco and Arris flavors) to all export the data in a way that is expected took much longer than expected. Erring on the side of caution I think in this case was the right thing to do, otherwise it could have been a major PR blackeye. Worse than delaying the meter for a year anyway.
No, obviously they are able to look at the data realtime if they can automatically throttle your speed for "excessive use" at any time. I just don't buy the excuses on the delay.
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espaeth
Digital Plumber
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said by fuziwuzi:

No, obviously they are able to look at the data realtime if they can automatically throttle your speed for "excessive use" at any time.
First off, the congestion management system isn't a throttle. According to all of the documentation provided, there is actually no integration of the congestion management system into the billing system. It's the billing/portal integration that likely caused the delay for availability of the user viewable meter.

Comcast has published documents that describe the operation of the congestion management systems here:

»downloads.comcast.net/docs/Attac···ices.pdf
»downloads.comcast.net/docs/Comca···0528.pdf


C_Chipperson
Monster Rain
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join:2009-01-17
00000
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2 edits
reply to fuziwuzi

said by fuziwuzi:

No, obviously they are able to look at the data realtime if they can automatically throttle your speed for "excessive use" at any time. I just don't buy the excuses on the delay.
I think its more complicated than that. (A question that does not put any words in anybody's mouth -) What are you saying, its some big conspiracy?


fuziwuzi
Not born yesterday
Premium
join:2005-07-01
Atlanta, GA

1 edit

said by C_Chipperson:

said by fuziwuzi:

No, obviously they are able to look at the data realtime if they can automatically throttle your speed for "excessive use" at any time. I just don't buy the excuses on the delay.
I think its more complicated than that. What are you saying, its some big conspiracy?
No, don't put words in my mouth. I'm simply asking a reasonable question: if they have been able to determine in realtime a customer's usage and take action on that information (which they have), then why can't they provide that same information, in realtime, to the customer?
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I think computer viruses should count as life. I think it says something about human nature that the only form of life we have created so far is purely destructive. We've created life in our own image.
- Stephen Hawking

AVonGauss
Premium
join:2007-11-01
Boynton Beach, FL

1 edit

1 recommendation

What makes you believe the customer usage information was being collected in realtime previously? Everything I have read makes me inclined to believe it was done in an offline batch mode.



jlivingood
Premium,VIP
join:2007-10-28
Philadelphia, PA
kudos:2

1 edit
reply to fuziwuzi

said by fuziwuzi:

No, obviously they are able to look at the data realtime if they can automatically throttle your speed for "excessive use" at any time. I just don't buy the excuses on the delay.
As others stated here, the congestion management system is not a throttling system. Were it so, you'd be throttled to XXXkbps for some period or time or for certain apps -- and that is just not the case. It is a congestion management system that is based in two different best effort QoS levels. As a result, the impact is about as fleeting and minimalist and light touch as you can get.

In any case, as you recognize above, that system looks at the most recent 15 mins of data usage, by examining usage in IPDR records (this is all openly documented, see »networkmanagement.comcast.net). But looking at the most recent 15 minutes and recording usage for 15M devices are two very different systems problems.
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JL
Comcast


fuziwuzi
Not born yesterday
Premium
join:2005-07-01
Atlanta, GA

2 edits

You're playing a game of semantics. If they cut your speed for a period of time because you're using too much bandwidth, that's throttling, in my opinion. You may attempt to call it something else, but I call it throttling..



jlivingood
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Philadelphia, PA
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2 edits

said by fuziwuzi:

You're playing a game of semantics. If they cut your speed for a period of time because you're using too much bandwidth, that's throttling, in my opinion. You may attempt to call it something else, but I call it throttling..
"If they cut your speed for a period of time because you're using too much bandwidth, that's throttling, in my opinion."

The system doesn't cut your speed, period. Ergo, not throttling. Please read the IETF document or FCC document describing how the system works on our Network Management website.
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Comcast

WernerSchutz

join:2009-08-04
Sugar Land, TX

1 edit

said by jlivingood:

said by fuziwuzi:

You're playing a game of semantics. If they cut your speed for a period of time because you're using too much bandwidth, that's throttling, in my opinion. You may attempt to call it something else, but that's being intellectually dishonest.
"If they cut your speed for a period of time because you're using too much bandwidth, that's throttling, in my opinion."

The system doesn't cut your speed, period. Ergo, not throttling. Please read the IETF document or FCC document describing how the system works on our Network Management website.
I am not sure if I understand here. I did read the documents and I understand that if a congestion situation occurs, the packets for a specific user are put in the "best effort" queue, so they may take a longer time to be delivered.

Speed=distance/time

Although the modem may still sync / display a line "speed" of 8 Mbit/sec, the packets taking longer to be delivered would be a de facto decrease of effective usable speed.

Is my understanding incorrect ?


espaeth
Digital Plumber
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When the line is congested, you aren't going to get your full rate regardless; that's what a circuit being congested means.

The congestion management system alters the priority of heavy user connections so that if the line becomes congested, their potential available bandwidth could be reduced, but only in relation to how much light users want to get access to bandwidth at the same time.


WernerSchutz

join:2009-08-04
Sugar Land, TX

1 edit

said by espaeth:

When the line is congested, you aren't going to get your full rate regardless; that's what a circuit being congested means.

The congestion management system alters the priority of heavy user connections so that if the line becomes congested, their potential available bandwidth could be reduced, but only in relation to how much light users want to get access to bandwidth at the same time.
So, then, if all conditions are true, the heavy user would see a reduction in speed.


jlivingood
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join:2007-10-28
Philadelphia, PA
kudos:2

2 edits

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said by WernerSchutz:

said by espaeth:

When the line is congested, you aren't going to get your full rate regardless; that's what a circuit being congested means.

The congestion management system alters the priority of heavy user connections so that if the line becomes congested, their potential available bandwidth could be reduced, but only in relation to how much light users want to get access to bandwidth at the same time.
So, then, if all conditions are true, the heavy user would see a reduction in speed.
That is typically not how these things are perceived by end users.

Here's a recent presentation I made, at »www.phoenix-center.org/symposium···good.pdf. Check out slide #5.

It would entirely depend upon the application being used. (Hey - my 3 hour download took 0.75 seconds longer than expected?)

Again, a throttling system would be like what is now common in the UK, which says that during peak hours, all non-HTTP traffic is throttled to XXXkbps. This is not that type of system. If you all want to group them together, then keep in mind you are losing all technical nuance between major network management system classifications.
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Comcast

WernerSchutz

join:2009-08-04
Sugar Land, TX

1 edit

said by jlivingood:

said by WernerSchutz:

said by espaeth:

When the line is congested, you aren't going to get your full rate regardless; that's what a circuit being congested means.

The congestion management system alters the priority of heavy user connections so that if the line becomes congested, their potential available bandwidth could be reduced, but only in relation to how much light users want to get access to bandwidth at the same time.
So, then, if all conditions are true, the heavy user would see a reduction in speed.
That is typically not how these things are perceived by end users.

Here's a recent presentation I made, at »www.phoenix-center.org/symposium···good.pdf. Check out slide #5.

It would entirely depend upon the application being used. (Hey - my 3 hour download took 0.75 seconds longer than expected?)

Again, a throttling system would be like what is now common in the UK, which says that during peak hours, all non-HTTP traffic is throttled to XXXkbps. This is not that type of system. If you all want to group them together, then keep in mind you are losing all technical nuance between major network management system classifications.
I understand the difference now, after looking at the slide and referencing your UK example.

Very helpful, thanks. I believe it is a good compromise and should be acceptable to all.


sortofageek
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reply to fuziwuzi

This is a re-hash of previous discussion in this thread ---> »The Bandwidth Limits/Congestion Management Topic

Please refer to the first post in that thread and relevant links. This topic will be linked there as well.
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