Now seems to be the trend to bring TCP to retro machines from first principles.

8088 PC's already have M Brutman's "mTCP" driver. And DogCow (D. Finnigan) has been working on and off on the "Sabina" networking suite for the original 128K Macintosh on the MacGUI site: https://macgui.com/sabina/ https://macgui.com/news/article.php?t=550

Though it's a been slow going, apparently because of a day job. (Also note that the MacGUI site now requires an account to read progress posts.)