Small tcp/iip stacks for microcontrollers
https://www.utwente.nl/en/eemcs/dacs/assignments/completed/bachelor/reports/B-assignment_vanderPloeg.pdf
Tcp/ip stacks (LwIP & uIP)
http://dunkels.com/adam/software.html
How to Implement TCP/IP and UDP/IP for Embedded Systems
https://barrgroup.com/Embedded-Systems/How-To/Embedded-TCP-IP