BDIX is the reason a movie from a local server arrives in minutes while an international download crawls. Here is what is actually happening to your traffic.
BDIX is the Bangladesh Internet Exchange. It is a physical place where local internet providers connect their networks to each other directly, instead of sending traffic abroad and back.
Two very different journeys
When you download from a server that is also connected to BDIX, your data travels a few kilometres between two Dhaka data centres. There is no submarine cable in the path and no international transit cost, so we can hand you the full speed of your package.
When you download from a server in Europe or the US, the traffic has to cross submarine cable capacity that the entire country shares. That capacity is finite and expensive, so international throughput varies with time of day in a way BDIX traffic does not.
Why we also cache Facebook and YouTube locally
Google and Meta place cache servers inside large ISP networks. Once a popular video has been fetched, it is served from a machine in Dhaka rather than from abroad. This is why a trending video loads instantly while an obscure one takes a moment - and it is also why we invest in local CDN nodes rather than only buying more international bandwidth.
What this means when you compare ISPs
Any provider can advertise a big number. What decides your real experience is whether they peer directly at BDIX, how much international capacity they actually own, and their contention ratio. Ask all three questions before you sign anything.