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Comment by dangrossman | Hacker News Reader

Is there any evidence TW is throttling versus these CDN servers you're being routed to simply being slow or overloaded?

I've noticed a change in YouTube buffering on FiOS the past few weeks as well. Other commenters here see it on Comcast. That may point to YouTube leaning more heavily on a CDN that can't handle the traffic (or some hop along the network to that CDN) rather than throttling by any one ISP.

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I have TW... and I just tried what the guy suggested.

One hell of a difference. I'm pretty shocked that they're doing this. I always thought it was Youtube that was being slow. http://www.youtube.com/watch?v=CB8UADuVM5A is an accurate depiction of what I just experienced right now.

That blocking the CDN improved your loading speed doesn't provide evidence of throttling. It's equally plausible that the CDN is slow for everyone, whether you're a Time Warner subscriber or not. The way to verify this would be to connect to that CDN from different ISPs with similar routes and see if there appears to be a hard cap in one connection but not the other.

I'm on TWC and this fix with iptables just made a massive difference. Whether it's throttling or not, I'm very impressed with the results.

You can easily check if you have a 4g (LTE, HSPA+, WiMax, etc.) and checking the same youtube video in HD. It's truly night and day and really got me so mad at Roadrunner once I discovered that.

Except you aren't necessarily hitting the same CDN when you connect via 4g

Ditto. I don't know how many times I've said "man, freaking Google owns Youtube, how can it take so long to load."

I've never been able to watch anything in 1080 or 720 unless I want to go run an errand while it's loading.

After running these commands...1080 streaming like a boss.

I have Verizon, as does a buddy of mine, and he and I have both been trading horror stories about how much YouTube sucks for the past few months.

I also applied the trick and now, magically, everything is quite a bit faster.

That said, while I'm not a network guy, this suggests that there's an issue with the YouTube CDN, not anything in particular with Time Warner or Verizon, unless they're doing something horrible relating to net neutrality.

My guess is just that there are a couple of CDN blocks that are preferred by the load balancers and they're saturated as a result, and blocking these IP ranges sends you to a less balanced block of CDNs.

Prior to blocking these subnets, I would have significant pauses every few seconds using 360p. I just tested a few 1080p videos with no issues and without buffering, which is about as big of difference as possible.

Whatever the problem is, it's not that those specific IP ranges are slow.

I just temporarily blocked everything except 74.125.0.0/16 (google's home address), 173.194.55.0/24 and 206.111.0.0/16 (the CDN).

Youtube is plenty fast using the CDN. It can be slow to start because it sometimes tries other addresses first.

I also don't know if there is any evidence. The cause can be many things. However, I can now verify without a doubt that this works. I turned the firewall rule on and off and tried multiple videos. When the rule is on, I can actually buffer an entire video like I could in the old days. With the rule off, it works, but is not so great.

I can only refer to anecdotal evidence I have seen on forums, Reddit, and from friends. That being said, it seems to be a stronger correlation with TWC rather than Verizon, but YMMV. Let me know if you uncover more details!

yeah I noticed youtube buffers are mad slow on FiOS these couple weeks.

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