I have a branch connected to the server via lessd-line connection with 64 kbps (=8 KB) band-width, the SDU in TNSnames.ORA is the default 2048 (=2 KB).
the question is :
if I change the SDU to 8 Kb so the packet to transfer will contains more data so the query will be faster?
Probably best to experiment with different values. You may also want to look at the OS settings for TCP/IP if thats what your using. Also you probably wont notice much difference unless you are returning a large amount of data.