A datacenter has layers of networking, and some of it is what we call "the core" or "the spine" of the network. Sometimes you need to shuffle things around, and you need to move things closer to core, and you can't because there are no ports. Or you procure the machines, and adding new machines requires some ports closer or at the core, and you are already running at full capacity there.
I mean, it can be dismissed like "planning/skill issue", but these switches are fat machines in terms of bandwidth, and they do not come cheap, or you can't get them during lunch break from the IT shop at the corner when required.
Being able to carry 1.2Tbit/sec of aggregated network from a dozen thin fibers is exciting, but scaling expensive equipment at a whim is not.
At the end of the day "network core" is more monolithic than your outer network layers and server layout. It's more viscous and evolves slowly. This inevitably corners you in some cases, but with careful planning you can postpone that, but not prevent.
Ok, that's good to know. But I still don't see how having congestion control be driven by receivers instead of senders makes it harder to fix than it is currently.
I mean, I don't actually see why you would need more ports at all. You still just have a certain number of machines that want to exchange a certain amount of traffic. That number is either above or below what your core can handle (guessing, again, at what the author means by "systemically overloaded").
A datacenter has layers of networking, and some of it is what we call "the core" or "the spine" of the network. Sometimes you need to shuffle things around, and you need to move things closer to core, and you can't because there are no ports. Or you procure the machines, and adding new machines requires some ports closer or at the core, and you are already running at full capacity there.
I mean, it can be dismissed like "planning/skill issue", but these switches are fat machines in terms of bandwidth, and they do not come cheap, or you can't get them during lunch break from the IT shop at the corner when required.
Being able to carry 1.2Tbit/sec of aggregated network from a dozen thin fibers is exciting, but scaling expensive equipment at a whim is not.
At the end of the day "network core" is more monolithic than your outer network layers and server layout. It's more viscous and evolves slowly. This inevitably corners you in some cases, but with careful planning you can postpone that, but not prevent.