[lemagedurage]

Even though they arguably shouldn't, some middleboxes assume that protocols don't change. They have made it hard for protocols such as TCP and TLS to evolve without breaking things.

Similarly, middleboxes have made it unviable to deploy protocols that aren't TCP or UDP based.

https://en.wikipedia.org/wiki/Protocol_ossification

[243423443]

I did not know that protocol ossification was a such a thing. Thanks for the link, it's an interesting article.

It says that middleboxes near the edge are more likely to be the cause of ossification. Are there any stats about that? Such as some manufacturers or software companies "infringing" on the end-to-end principle more often than others?

[Karrot_Kream]

Not sure about stats but if you hang out in networking forums, you'll see netops complaining about bad implementations of protocols in their networking gear forever. This has been a huge problem in several protocols, everything from SCTP to IPSec to UDP RTSP.