Learning tips for analytics and how to include analytics license in developer org 
 

TCPIP vs external interrupt
Why running TCPIP inserts random delays into the external interrupt response time. External interrupt has priority 7 and uses SRS. Nothing else with priority 7.  The TCPIP server is a Harmony example.
If the server is not running, the external interrupt delay is constant  (1us).
After starting the server, it changes between 1 - 2 us.
I do not know what to try anymore.