On the topic of WAN vs DC it's about reliability. A lot of the engineering behind TCP assumes an unreliable transport, but in a data center context a lot of the

On the topic of WAN vs DC it's about reliability. A lot of the engineering behind TCP assumes an unreliable transport, but in a data center context a lot of the unreliability doesn't exist, or can be engineered out of the network infrastructure you use. A good example of this in my space is video over IP (ST 2110), which is over RTP/UDP, but RTCP (for retransmission and rate control) is much more of a vestigial component, and if I remember correctly is entirely optional in the specs. A lot of the SDN solutions even default to not carrying the RTCP back channel. Now, in the video over IP space, there is essentially zero time available for retransmission, so such packet loss would be better handled as a dropped frame or audio packet, but it's not like this is an expected outcome of using UDP in such a controlled environment as a dedicated video transport network