I already have a purpose for it. For that I need to have acceptable networking performance to make it work.
And acceptable means about 20 TCP/IP connections per seconds. Every connection has to transfer a JSON messages of about 300 bytes.
If there was DTLS support in the W5100 or FPGA, then I could have had a more relaxed MSX because of the way more efficient message format.
I will see where the bottlenecks are and if I can work around it.