Comcast Outlines New Broadband Policy 350
Slatterz writes "US cable provider Comcast has presented its long-term solution for managing broadband traffic. The new system is set at putting to bed a minor scandal that erupted around the company when it was found that Comcast deliberately limited traffic for certain applications. The company said that under its new system, traffic will be analyzed every fifteen minutes. Users who are found to be occupying large amounts of bandwidth will be placed at a lower priority for network access behind users with less bandwidth-intensive traffic. The new system will not replace or be related to the company's earlier installment of bandwidth caps, which limited a user's data intake to 250GB per month."
Pretty sure this was in place for a while now (Score:1, Informative)
...As my cable modem service slows to a CRAWL if I have a torrent open for more than 20-25 minutes. Once you terminate the d/l, it stays that way for 20-25 minutes or so... The throttling is so severe that DNS requests time-out... Not really that awesome of a solution, IMO.
Re:Dang... (Score:5, Informative)
I don't know what you're talking about. Where I live, I have two options.
Beats my old options: Comcast, unreliable ISDN, or 12.6Kbps dial-up.
My take on this? It's a much better policy than just randomly killing connections that look like they might be doing something that may be using large amounts of bandwidth.
Re:OK, but can we help? (Score:1, Informative)
Technically that is your responsiblity by having a router that has QoS support and you set your gaming console to higher priority over everything else so that you don't lag out when your little brother decides to watch the latest music videos on youtube.
Re:OK, but can we help? (Score:5, Informative)
The types defined in the RFC are:
I believe an extension also had a "maximize security" option as well.
Alas, almost nothing supports these flags, and I believe a later RFC has proposed reusing the QOS bits in the IP header for an incompatible use.
Re:250GB (Score:4, Informative)
So they are saying... (Score:2, Informative)
That all the World of Warcraft players, when installing the new patch for the Lich King, will now be subject to slower download rates cuz they need a 1GB patch?
Woo hoo!?!
Re:Pretty sure this was in place for a while now (Score:5, Informative)
That's probably not throttling. Same thing happens to my cousin, and the same thing happens to me (though not as bad.) Every seed and leech in that torrent is still hammering your connection and timing out, requesting what parts you're advertising. At least that's what my firewall logs seem to suggest.
Power cycle your cable modem and get a new IP address. Your former cloud will no longer be DDoSing your connection.
This Statement Is False (Score:3, Informative)
"Comcast deliberately limited traffic for certain applications."
That's wrong. It shouldn't be in past tense. Some IPs on Comcast space still drop p2p connection after 30 seconds. Dropping is common. Dropping consistently at 30 +/- 5 seconds from those IP blocks is too much coincidence to bear.
"The new system will not replace or be related to the company's earlier installment of bandwidth caps, which limited a user's data intake to 250GB per month."
Of course it won't replace their previous 'solution'. It will apply to uploading, as does their connection dropping, not to downloads.
If they can get their quotas to fly, they'll next offer to keep users off their slowdown list for a fee. That way they can charge users more without having to up their bandwidth.
Re:Dang... (Score:1, Informative)
Yep same thing here. ATT DSL is 6 MBPS for me ALL the time and I have had no issues with it whatsoever.
I know a fix for this (Score:4, Informative)
Re:Dang... (Score:5, Informative)
Here's an email from one of Comcast's engineers recently sent to Dave Farber's Interesting People mailing list. It clarifies the policy quite well:
From: "Livingood, Jason"
Subject: Clarifying Misconceptions of the New Comcast Congestion Mgmt Syste
Hi Dave
I wanted to try to clear up a misconception about how the new Comcast congestion management system works. I believe we have both heard people complain that they fear that they will be unable to use their provisioned speeds during off-peak hours, for example, or at all times of the day, or that users are somehow throttled to a set speed. Neither of these two things are correct. Part of the problem appears to be confusion over how a user's traffic enters a lower priority QoS state, so I hope to clarify that here
In order for any traffic to be placed in a lower priority state, there must first be relatively high utilization on a given CMTS port. A CMTS port is an upstream or downstream link, or interface, on the CMTS in our network. The CMTS is basically an access network router, with HFC interfaces on the subscriber side, and GigE interfaces on the WAN/Internet side. Today, on average, about 275 cable modems share the same downstream port, and about 100 cable modems share the same upstream port (see page 5 of Attachment B of our Future Practices filing with the FCC, available at http://downloads.comcast.net/docs/Attachment_B_Future_Practices.pdf [comcast.net]). We define a utilization threshold for downstream and upstream separately. For downstream traffic, a port must average over 80% utilization for 15 minutes or more. For upstream traffic, a port must average over 70% utilization for 15 minutes or more
When one of these threshold conditions has been met, we consider that individual port (not all ports on the CMTS) to be in a so-called Near Congestion State. This simply means that the pattern of usage is predictive of that network port approaching a point of high utilization, where congestion could soon occur. Then, and only then, do we search the most recent 15 minutes of user traffic on that specific port, in order to determine if a user has consumed more that 70% of their provisioned speed for greater than 15 minutes. By provisioned speed, we mean the "up to" or "burst to" speed of their service tier. This is typically something like (1) 8Mbps downstream / 2Mbps upstream or (2) 6Mbps downstream / 1Mbps upstream
So how does this work in action? Let's say that a downstream port has been at 85% utilization for more than 15 minutes. That specific downstream port is identified as being in a Near Congestion State since it exceeded an average of 80% over that time. We then look at the downstream usage of the ~275 cable modems using that downstream port. That port has a mix of users that have been provisioned either 8Mbps or 6Mbps, so 70% of their provisioned speed would be either 5.6Mbps or 4.2Mbps, respectively. So let's use the example of a user with 8Mbps/2Mbps service on this port. In order for their traffic to be marked with a lower priority on this downstream port, they must be consuming 5.6Mbps in the downstream direction for 15 minutes or more, while said port is highly utilized
Once that condition has been met, that user's downstream traffic is now tagged with the lower priority QoS level. This will have *no* effect whatsoever on the traffic of that user, until such time as an actual congestion moment subsequently occurs (IF it even occurs). Should congestion subsequently occur, traffic with a higher priority is handled first, followed by lower priority (and this is not a throttle to X speed)
I hope this helps. You can others can feel free to contact me directly if you have any questions
Regards
Jason Livingood
- Engineering & Technical Operation
For verification, you can find the original in the IP Archives. [listbox.com] Date of the email is 2008-09-24 12:37:35
Re:Backwards? (Score:3, Informative)
Clarification: when they say "lower priority", they mean "higher latency". It shouldn't noticeably affect streaming video or torrents, because those require high bandwidth, but not low latency. It's not the end of the world if you need to wait 5 seconds for your YouTube video to start streaming, as long as it doesn't pause to buffer while you're trying to watch the video.
On the other hand, VOIP and online games -- which don't require high bandwidth -- will benefit from better latency than they currently get. (As I understand it, the telcos have already been doing this for VOIP, but not in an unbiased way.)
This is actually a sudden outbreak of common sense. Of course, Comcast still has bandwidth caps, but that's nothing new if you were around in the days of dial-up. Dial-up was closer to a free market, though, which is how we ended up with unlimited bandwidth deals to begin with.
Up here in Canada, Bell has been forced to lease their bandwidth to third-party ISPs, and that helps (we probably have two dozen options for ISPs in Toronto) but it's not quite ideal [slashdot.org].
Re:Look. (Score:3, Informative)
If you seriously think you are going to exceed 250GB a month, spend the extra money and get a business account. If you are that heavy of an internet user, moving to 70 bucks a month or so shouldn't be that big of a deal.
Guess what, I have the Comcast Business 16/2 Account at home - and we got the "You now get 250GB of monthly bandwidth " e-mail just like everyone else....
unlimited usage. that was my contract. (Score:3, Informative)
That was their selling point.
I want a lower price. What makes ISPs so brash that they can just alter the terms of an agreement to suit them and we're expected to pay the same price.
Re:Pretty sure this was in place for a while now (Score:2, Informative)
Check your outbound usage.
Considering cable connections are asynchronous if your outbound pipe fills up your whole connection will slow to a crawl since the acknowledgment packets will be unable to be delivered outbound in a timely manner to tell the nodes you are downloading from to send more data.
Basically if you have 500KB/s inbound and 100KB/s outbound, if you saturate all 100KB/s outbound you can expect your inbound traffic to drop to 100KB/s or less as well as increasing the latency over the connection to 2 seconds or more (on some connections).
The way to fix this is to throttle your outbound maximum traffic in your BT client to less than 80% of your maximum cap as tested through sites like speedtest.tds.net or whatever your favorite site is. This should allow for overhead traffic like ACK packets to leave your network in a timely manner.
Re:Backwards? (Score:3, Informative)
"So they're saying that if I am doing something that requires more bandwidth, I will get less bandwidth; and when I don't need much bandwidth, they're going to give me more? I'm really confused by this. Can anyone make sense of this for me?"
You got it wrong. If you are using a lot of bandwidth you do NOT get throttled down. You are simply put at the end of the queue and a few shorter network packets are allowed to go to the front.
What they have is a fixed size pipe. When they see more demend for bandwidth then they have tey go into "rationing mode". In this mode they let the user with the lowest bandwidth requirements in front. This is a very old idea and comes from the scheduling algorithms used on operating systems from about the 1960's called "shortest job first" doing this can be shown to make the entire system seem more responsive to the greatest number of users. What they are doing is maximizing the amount of customer satisfaction.
Will they fix oversaturation? (Score:2, Informative)
Re:ENCRYT, ENCRYPT, ENCRYPT (Score:3, Informative)
All they need to know is that there is alot of it - they don't care what it is.
Re:Dang... (Score:2, Informative)
Let's see... Google calculator tells me my 4.2Mbps is roughly 525KB/s.
Maybe it's because I only get files in serial, but in the year I've had Comcast I've pretty much never come anywhere near that, especially at a sustained speed.
(s/I/my friend/g?)
Re:What...? (Score:2, Informative)
So they should be able to slow my traffic down because I'm trying to actually use their advertised bandwidth? How is me wanting what I was sold unreasonable?
This is a little unreasonable, yeah, because they don't advertise anything that ought to make an intelligent person instantly assume that they can run their 6 or 8Mb connection all-out, 24/7. It's been a very long time since I've seen them advertise "unlimited" anything. There might have been a point, a few years back, when you could make an argument that they'd advertised unlimited service and ought to deliver on that, but it hasn't been the case for a while.
They are very careful, at least in every ad I've seen, about only advertising peak speeds as being "up to" or "burst." The connection is capable of it, in other words, but it's not meant to be used that way continuously. If this offends you, that's fine, but it shouldn't be any more offensive than a car manufacturer printing up the power generated by an engine while at redline, or a CD/DVD drive manufacturer highlighting their burst speed while burying their sustained speed in the small print. If your problem is with advertising as it is carried out in the U.S. today generally, than I'm all with you. But Comcast isn't that much worse than the norm.
While I wouldn't mind if some states' Departments of Consumer Protection mandated that ISPs display their continuous, sustainable transfer rates alongside and in the same size/typeface as their burst speeds, there's no requirement for them to do anything like that right now. (It'd be amusing to see them advertising "101kB/s" internet, since that's what the 250GB cap works out to be.) It's up to consumer to read the small print and know what they're buying.
yes they are limiting it to 250GB (Score:2, Informative)