It's time to replace TCP in the datacenter (2023)

I wonder why Fibre Channel isn't used as a replacement for TCP in the datacenter. It is a very robust L3 protocol. It was designed to connect block storage devices to servers while making the OS think they are directly connected. OSs do NOT tolerate dropped data when reading and writing to block devices and so Fibre Channel has a extremely robust Token Bucket algorithm. The algo prevents congestion by allowing receivers to control how much data senders can send. I have worked with a lot of VMware clusters that use FC to connect servers to storage arrays and it has ALWAYS worked perfectly.

Fibrechannel is far too expensive, you need expensive switches, cables/transceivers and cards in addition to the Ethernet you'll need anyways. And this Fibrechannel hardware is quite limited in what you can do with it, by far not as capable as the usual Ethernet/IP stuff with regards to routing, encryption, tunneling, filtering and what not.

Similar things are happening with stuff like Infiniband, it has become far too expensive and Ethernet/ROCE is making inroads in lower- to medium-end installations. Availability is also an issue, Nvidia is the only Infiniband vendor left.