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Cuba's Internet Routing Is Messed Up
Internet access in Cuba has gotten far better in the last year, thanks in large part to thawing relations between Cuba's government and the U.S. In the case of a censorship-heavy, technology-impaired regime, though, "better" doesn't necessarily mean good. Northwestern engineering professor Fabián E. Bustamante and graduate student Zachary Bischof decided to quantify the performance of Cuban internet connections, and found them "perhaps even worse than they expected," with regards to routing in particular. Reader TheSync writes with this excerpt: During their study, Bustamante and Bischof found that when a person in Havana searched for a topic on Google, for example, the request traveled through the marine cable to Venezuela, then through another marine cable to the United States, and finally landed at a Google server in Dallas, Texas. When the search results traveled back, it went to Miami, Florida, up to the satellite, and then back to Cuba. While the information out of Cuba took 60-70 milliseconds, it took a whopping 270 milliseconds to travel back.
Satellite ISP customer here. Tonight I'm averaging about 610ms pings. That means the skies are clear both where I live and where my ISPs has their ground station. 800-1000ms pings are not uncommon for me.
Probably not a "problem", more likely it is a "decision". BGP routing isn't really about finding the fastest or best route, though InterNAP has some special sauce they can add via an appliance to help with that. It is about finding the "shortest" in terms of number of ASNs traversed, often weighted by company policy about what is cheapest. A satellite link directly to Cuba is probably fewer ASN hops than a cable to Venezuela and another cable to Cuba, so BGP picks that as best. The company pushing the traffic out the satellite either don't know to prefer the other path, have congestion on that link (just because it comes in that way doesn't mean it is going out the same link return, and there could be asymmetric loading), or it is more expensive to pass it to that provider. And it could be that using the exact same path to return traffic reduces latency, but increases loss due to overloaded links, so the satellite may provide a way better experience even if it is slower.
BGP routing can be tricky.