This is more "home networking" than "homelab," but I imagine the people here might be familiar with what in talking about.
I'm trying to understand the logic behind ISPs offering asymmetrical connections. From a usage standpoint, the vast majority of traffic goes to the end-user instead of from the end-user. From a technical standpoint, though, it seems like it would be more difficult and more expensive to offer an asymmetrical connection.
While consumers may be connected via fiber, cable, DSL, etc, I assume that the ISP has a number of fiber links to "the internet." Those links are almost surely some symmetrical standard (maybe 40 or 100Gb). So if they assume that they can support 1000 users at a certain download speed, what is the advantage of limiting the upload? If their incoming trunks can support 1000 users at 100Mb download, shouldn't it also support 1000 users at 100Mb upload since the trunks themselves are symmetrical?
Limiting the upload speed to a different rate than download seems like it would just add a layer of complexity. I don't see a financial benefit either; if their links are already saturated for download, reducing upload speed doesn't help them add additional users. Upload bandwidth doesn't magically turn into download bandwidth.
Obviously there's some reason for this, but I can't think of one.
Cable does this because of the inherit bandwidth restrictions it comes with, along with being able to price gouge customers to pay for faster upload. Coax (really, DOCSIS) and the related infrastructure around it simply does not have the bandwidth to offer symmetric connections, at least for companies like Comcast (yuck). They will wait until it's absolutely necessary to upgrade their infrastructure to support faster upload. Even then, it likely will not be symmetric since there needs to be channels for TV/phone too.
Fiber has much more bandwidth, and the related infrastructure does too. That's why it's almost always symmetric.