I've noticed a disturbing trend in the last month with my Comcast internet service: in the evening my internet connection slows to a crawl. And by a crawl, I mean my normal 20 Mbps (Megabits-per-second) download speed drops to an average of 0.73 Mbps! The upload speed is just the same as always, about 2.5 Mbps.
With all the news reports about Comcast blocking or throttling communications through Level 3's backbone because the popular streaming video provider NetFlix is hosted on Level 3 servers, I am suspect the slowdown is due to one of two reasons:
- Comcast is indeed throttling the connection speed when a user's traffic comes from Level 3, or
- Comcast's own network does not have the bandwidth to handle massive amounts of users who come home from work, and watch streaming video over the internet.
So, I decided to conduct some tests. (Yes, this is what us geeks do for fun!)
Both are very similar: Between 19 and 20 Mbps download, and a little over 3 Mbps upload.
The picture at 8pm in the evening is very different! According to Comcast's Speed Test, I am getting almost 3 Mbps down and over 2 Mbps up. Not great, but not enough for the Comcast Technical Support Representative to be concerned about. (Seriously?)
However, using SpeedTest.net (which is NOT on Comcast's network, and requires the traffic to traverse Level 3's backbone) a very different picture emerges: I am only getting 0.73 Mbps down! My upload speed, interestingly, is not affected.
WHY THIS IS SIGNIFICANT
For years, I've used SpeedTest.net as my reference because it is representative of "normal usage." Why is that? Because most traffic comes to your computer via outside backbone providers! Think about it… If you live in Florida and email your brother in California, it is NOT going to stay exclusively on Comcast's network. That file is going to bounce across several backbone providers on its trip.
The same is true if you are watching YouTube, playing an online game, buying or listening to music, or any other internet activity. The chances of your traffic staying on your own Internet Service Provider's network is slim at best.
When I called Comcast for tech support, the very first thing the representative had me do was conduct the speed test using Comcast's own Speed Test servers. Which of course are going to have a much better rate because it's staying inside Comcast's own backyard.
And… They are not throttling traffic to their own servers!
It's interesting to note also that a year ago and earlier, Comcast's own installers were using the third-party SpeedTest.net site for bandwidth testing. So why now are the representative downplaying any other speed test site over their own?
Because they are not throttling traffic to their own servers!
This is very convenient for Comcast support representatives, so they can easily point out that the customer is getting a sufficient (notice I did not say "good") connection to the network "as agreed to in their terms of service."
This connection and speed test is not a realistic portrayal of what the user sees when they are on the internet, and it's sad they are using this argument to shut customers up, and get the support call marked as a "resolved issue."
Most customers will go "Oh, I guess it's not so bad," when they see the speed tests via Comcast's site, and not question it any further. It seems to be concrete proof that you have a good internet connection. But the reality is your 20 Mbps service is --in the evening when everyone around you is online-- running as slow as an ancient DSL connection!
THE CONDITIONS LEADING UP TO THIS POINT
2010 saw a dramatic increase in the number of people using streaming movie services. The effects of this transition were widespread: we've watched most of the video rental stores close up shop, and even record stores are shrinking inventory and closing now as most people would rather preview and purchase music online.
With millions of people turning to streaming video instead of renting DVD's or watching whatever happens to be on cable TV, the traffic on all backbone providers have multiplied exponentially. As a whole, the public has become extremely "bandwidth hungry" without even realizing it.
This is why Comcast and Level 3 are fighting over the agreements made regarding letting each other's traffic pass back and forth. This is also why almost all internet providers (and cell phone companies with data plans for smart phones) are starting to move to tiered data plans, where the more data you use, the more you pay.
They know their networks are not capable of handling the traffic if we ALL go online and watch movies at the same time: they need to invest in a lot more equipment to be able to handle that kind of traffic, and that money's gotta come from somewhere.
SUMMARY OF FINDINGS
Since both Comcast's and third-party speed test show a significant reduction in download speeds in the evening, this indicates that Comcast's local architecture (internet over coaxial cable into neighborhoods and apartment complexes) is not able to handle the increased load of all the traffic that is generated when people come home from work and school and get online.
The disparity between Comcast's speed test and third party speed tests indicates that there is indeed a network slowdown when traffic is coming from outside Comcast's network.
Given the rather sudden change (in November and earlier, both speed tests showed the same results at all hours) AND the fact that Comcast is complaining about incoming traffic from Level 3's backbone (primarily because of NetFlix), leads me to the conclusion that Comcast has indeed started throttling network traffic.
Of course, it ~could~ indicate problems on Level 3 or other networks, or that those providers are throttling traffic. However, due to Comcast's threats to charge Level 3 more for incoming traffic (or else they will throttle it) in the last 3 months, it seems clear that throttling is in place.
What does this mean for the average Comcast user? We're paying for 20 Mbps service in the evening whernwe actually use it, and we're now getting a tiny fraction of that: 0.73 Mbps.
Here's the math: 20 Mbps / $50 monthly = $2.50 per Megabit of download speed.
According to that math, I wonder how Comcast would feel if I paid my bill according to my real download rate? Here's the math:
$2.50 (calculated dollar per Megabit rate) X 0.73 (my actual evening download speed) = $1.83 monthly.
That seems fair to me.