Canadian checking in here.
**This comment has been updated with better info and links for the sake of clarity, see below for new info**
>As far as I can tell from my research into how this affects Canada, there is only one undersea fiber cable linking Canada's internet to the rest of the world that doesnt go through the US first. That link goes to Greenland and reportedly has had frequent issues since it was built due to poor construction. Aside from this Greenland link, all other wired Canadian internet traffic goes through the US first before going to the rest of the world. The US could effectively cut Canada off from the internet if it wanted to.
>However, there is a proposal to built a new, modern fiber link through the Canadian arctic that would link London, UK with Tokyo, Japan. This would significantly reduce latency between Western Europe and East Asia while also bypassing the mainland US. It would also provide gigabit internet access to thousands of remote Inuit communities in the Canadian Arctic, which could have life changing effects on their economies.
Thanks to /u/RcNorth and /u/markszpak for highlighting [this more detailed map](https://www.submarinecablemap.com/#/submarine-cable/gtt-atlantic
) than the ones I based the previous version of this comment on. This more detailed map clearly shows that there are 3 fiber links from Halifax to the UK in addition to a fiber link up to Greenland that I mentioned previously.
However as described by /u/SoontobeSam:
>As a former network operations technician for a Canadian ISP, this is correct, telegreenland's cable is the only subsea fiber I am aware of that does not enter the US before Canada, our other main access routes are in Toronto and Vancouver, but both connect to the US to access international networks.
I can also confirm that their network uptime is mostly ok, but when they do have issues it takes forever to get any progress and dealing with ongoing non outage issues is difficult, also Newfies and Scots have a serious language barrier even though they're both speaking "English".
So while my initial remarks regarding the US basically being the gatekeeper for Canada's access to the wider Internet may be more or less correct, I was incorrect in saying that the Greenland fiber link is the ONLY fiber link Canada has to the rest of the world. While the Toronto, Halifax, and Vancouver links /u/SoontobeSam mentioned appear to all go through the US in some way first which technically restricts Canada's direct access through those links.
By popular request here is [the link to the site](http://qexpressnet.com/system/
) for the fiber link through the Canadian Arctic that I mentioned previously. The project was formerly known as Arctic Fiber, but has been re-branded as the Quintillion Cable System after the name of the company task with installing the cable. Yes, you read that right, this project has gotten the green light since I last checked up on it (I didn't have time to check on my way to work when I commented originally). They just completed Phase 1 which covers Alaska, and will be starting the Phase 2 to expand through Asia to Tokyo soon. Quintillion has also built a terrestrial link through Alaska and down to the mainland US in order to provide connection to existing connection hubs on the west coast.
*UPDATE 2: Just have to highlight these two awesome users comments:*
User /u/KrazyTrumpeter05 posted [an awesome comment](https://www.reddit.com/r/askscience/comments/7ez85x/with_all_this_fuss_about_net_neutrality_exactly/dq9ir7v/
) with more info about Canadian Fiber connections, and also linked to [this 293 report](http://subtelforum.com/products/submarine-cable-almanac/
) they claim to have played a major role in writing about Internet Fiber connections around the world. Thanks for the fascinating info!
User /u/Fochang1 posted [this fascinating comment](https://www.reddit.com/r/askscience/comments/7ez85x/with_all_this_fuss_about_net_neutrality_exactly/dq9ic13/
) about how South American/Caribbean nations have a similar issue with the US acting as their Internet gatekeepers. They linked to [this insane Internet Exchange Point](https://en.m.wikipedia.org/wiki/NAP_of_the_Americas
) in Miami that routes most of South/Central America's internet traffic. Thanks for sharing this incredible perspective that Canadians like myself would otherwise be oblivious to!
**Some thoughts on the impact of Arctic Fiber**
The fact that this project is actually being built is incredible, because it will mean a huge boost in connection for remote arctic communities that open up massive new economic and information exchange opportunities to these historically very isolated regions. I can't wait to see what the Inuit peoples of Canada's arctic will do with this new link to the outside world. Reconciliation between Canada's indigenous and non-indigenous peoples has become a major focus for Canada in recent years, with the Canadian government [set to fully implement into law](http://www.cbc.ca/news/politics/wilson-raybould-backs-undrip-bill-1.4412037
) a 2007 [UN declaration on the rights of Indigenous peoples](https://www.un.org/development/desa/indigenouspeoples/declaration-on-the-rights-of-indigenous-peoples.html
). There is a long way to go for reconciliation, and it has been a very rocky road so far, but I hope that this new Fiber link will open up new ways for a large portion of Canada's indigenous population to showcase their own culture to the world and make new economic opportunities for their communities in the digital marketplace.
If you for some reason read through everything to this point, thanks for reading :)
I don't see how any of it would have any impact on anyone outside the u.s.
If you're in Canada or elsewhere, and you're accessing a service in California, the Layer3 provider isn't going to be throttled at all.
The throttling has to happen ONLY at the client level inside the U.S. at the modem for the service to be able to be upgraded as a sellable package, therefore if your ISP is Comcast, their Network HAS to stay fast all the time so they can market those individual services to paying customers selectively.