im new to linux kernel compilation,

i want to modify the linux TCP window size value to windows TCP/IP default values,
how can i cahnge that can any one o u plz tell, how to change it in kernel level,

i changed /proc/sys/net/icore/rmem_max/, /proc/sys/net/icore/rmem_default/, /proc/sys/net/icore/wmem_max/, /proc/sys/net/icore/wmem_default/ to 1000, after changing that, i use tcpdump or ettercap , in that result it shows some winow size values not what im gave in that files,
can any one please tell me it's urgent...
thanks in advance