Comcast's New Throttling Plan Uses Trigger Conditions, Not Silent Blocking

clang_jangle writes with this excerpt from The Inquirer outlining Comcast's new traffic-throttling scheme, based on information from Comcast's latest FCC filing. "Its network throttling implements a two-tier packet queueing system at the routers, driven by two trigger conditions. Comcast's first traffic throttling trigger is tripped by using more than 70 per cent of your maximum downstream or upstream bandwidth for more than 15 minutes. Its second traffic throttling trigger is tripped when the Cable Modem Termination System you're hooked-up to – along with up to 15,000 other Comcast subscribers – gets congested, and your traffic is somehow identified as being responsible. Tripping either of Comcast's high bandwidth usage rate triggers results in throttling for at least 15 minutes, or until your average bandwidth utilisation rate drops below 50 per cent for 15 minutes."

Comments

Re:Laws

[Saishuuheiki]

Here in america we prefer a system where the ISP gets a monopoly and can advertise what you could get, not what you will get ...sadly

Summary Backwards

[HoboCop]

I read the FCC paper.. the summary is full of errors. The individual user does not get throttled until the entire CTMS port is in a congested state (that's 80% downstream, 70% upstream). And 'throttled' is a loose term.. if the bandwidth is available you get it. You are throttled if there are lower volume users on the shared pipe, and even then they just get a higher priority. Depending on how bad the congestion is, you might not even notice this.

Oops, left something out

[sunking2]

This part is rather important, yet amazingly was left out of the summary.

During the time that a subscriber's traffic is assigned the lower priority status, such traffic will not be delayed so long as the network segment is not actually congested. If, however, the network segment becomes congested, such traffic could be delayed.

So what they are really doing is lowering your priority. If there is no real congestion then you notice no difference. If things get saturated then your packets are delayed before other peoples.

Just to be clear...

[fahrbot-bot]

From the actual PDF:

• ... create two Quality of Service ("QoS") levels for Internet traffic going to and from the cable modem: (1) "Priority Best-Effort" traffic ("PBE"); and (2) "Best-Effort" traffic ("BE").
• During the time that a subscriber's traffic is assigned the lower priority status, such traffic will not be delayed so long as the network segment is not actually congested. If, however, the network segment becomes congested, such traffic could be delayed.
• Given our experience so far, we have determined that a starting point for the upstream Port Utilization Threshold should be 70 percent and the downstream Port Utilization Threshold should be 80 percent. (The term "port" as used here generally contemplates single channels on a CMTS, but these statements will apply to virtual channels, also known as "bonded groups," in a DOCSIS 3.0 environment.) -- (Basically, a "port" is the neighborhood connection.)
• (Given the above) When a subscriber uses an average of 70 percent or more of his or her (individually) provisioned upstream or downstream bandwidth over a particular 15-minute period, that user will be in an Extended High Consumption State.

Simply put, there are four steps to determining whether the traffic associated with a particular cable modem is designated as PBE or BE:

1. Determine if the CMTS port is in a Near Congestion State.
2. If yes, determine whether any users are in an Extended High Consumption State.
3. If yes, change those users' traffic to BE from PBE. If the answer at either step one or step two is no, no action is taken.
4. If a user's traffic has been designated BE, check user consumption at next interval. If user consumption has declined below predetermined threshold, reassign the user's traffic as PBE. If not, recheck at next interval