The Internet Connection API improves performance because it does not go through CGI processing. See details in the Internet Connection Web Programming Guide:
http://www.ics.raleigh.ibm.com/pub/icswpg.htm
Details on which systems can use ICAPI and additional information is in the README file. These are the steps to configure Net.Data to run with ICAPI on your server:
WWW\CGI-BIN\
The other Net.Data DLLs or shared libraries must be in the server's DLL or shared library directory.
Service /cgi-bin/db2www* c:\www\cgi-bin/dtwicapi:dtw_icapi*