The same reason you have traffic jams at certain times of day and not others. The same reason Walmart is a major fustercluck on Black Friday. Countless other real life examples where a bunch of people clump up and clog up the flow of traffic in an area.
Everyone is getting crammed into a handful of exchanges along with everyone else (Ormuco peers with only 5 ISP's for Montreal and everyone has to ride one of those networks to get in). Ormuco themselves have tons of bandwidth to support the game's traffic, but either our ISP's or the ones they partner with to get to Ormuco have not negotiated enough upstream bandwidth to get us from here to here. And that leads us to another part of the problem-- hot spots of congestion throughout the US as well. That is again an issue of the ISP's not arranging enough upstream bandwidth at popular exchange points to properly support the high bandwidth plans they have been selling us locally.
Look at the route you take. You may see hops in areas like LA or elsewhere in Southern California, then coming across the US and up the east coast there are a few hot spots around TX, OH, most everyone makes a stop in Chicago, and eventually most everyone hits either the Washburn/DC area and/or the NY/NJ area. Then you finally hit Canada. Unless you came across one of the two or three routes around Vancouver you have about a 50/50 shot of going right to Montreal..other wise you are likely to tap Toronto first. If you are east of the US most of you are coming in through Maine, Nova Scotia, or NY/NJ. Note also that most the traffic west of California comes into the US by way of South Cali--only a small portion comes in up near Canada by way of Washington/Vancouver (this is may be an election made by the ISP's servicing those regions--someone like Telstra may be able to choose either a northern or southern path with the undersea lines).
Lots of choking points in heavily populated areas, that also have heavily utilized networks during prime time--lots of people using the internet in general, clogging the pipes.
Someone in LA can be impacted by issues occuring in Dallas, Austin, Chicago, New York---or any combination of all of them.
Edit:
Finally got home so I can pull up some links to some visuals to help illustrate the problem. Here are network maps for the 5 peers Ormuco uses:
Tata Communications (will show AS6453 in traces)
Notice how they only have TWO corridors for service into the US---and they connect in the North East---as in the NY/NJ area.
Level 3 Communications
Zoom in and you will see once again essentially TWO corridors for service to the US--by way of the north east again as well.
Cogent Communications
This one actually has an image that should render in the forums. Notice once again the limited pathways specifically into Montreal (again, only TWO):
Alter.net/UUnet (their Verizon Business peer)
It's not as easy to follow as the others, but if you zoom in on the Global mesh...you will see TWO corridors feeding into Canada
TiNET/SPA (actually GTT Telecom)
Another one that can render directly in the forum. Notice once again, only TWO corridors specifically into Montreal for the US (looks like a third, but it actually slingshots Vancouver/Toronto first to get to Seattle--it condenses into the one line between Toronto and Montreal at the end)
Until they added Verizon this past year, over 2/3's of the traffic was on Level3, TATA, and Cogent--that's right, it used to be MUCH worse. Here is their current peering breakdown:
Ormuco's Registered IPv4 Peer listing
Code:
AS701 Verizon Business/UUnet
AS3356 Level 3 Communications, Inc.
AS6453 TATA COMMUNICATIONS (AMERICA) INC
AS174 Cogent Communications
AS3257 Tinet SpA
THAT is why we have congestion problems. These top tier ISP's have massive bandwidth available. If you look at their maps, you see how they provide a lot of cross-country transit--you likely use some of these same ISP's to access lots of content elsewhere. But along the particular exchange points to get to Montreal, their are still peering agreements that are not providing enough bandwidth to properly support the loads along the way to Montreal. A major part of the responsibility to remedy that is on the last mile ISP's we purchase internet service from.
Here is a post I made in another thread that has links to articles posted by professionals in the field (these guys have been going to the FCC for some time now about the issue, btw) and statistical data/outage maps to further demonstrate things in case anyone wants to learn more:
http://forum.square-enix.com/ffxiv/t...=1#post3149203