How to set value of udp_max_buf

Addition info:
I have already set the value by using:
ndd -set /dev/udp udp_max_buf 1048576
I just want to know how to set this value permanently in  kernel parameter file.

This is from SUN's Tunable Parameters Guide -
To set a TCP/IP parameter across system reboots, include the appropriate ndd
command in a system startup script. Use the following guidelines to create a system
startup script to include ndd commands:
Create a script in the /etc/init.d directory and create links to it in the
/etc/rc2.d, /etc/rc1.d, and /etc/rcS.d directories.
The script should run between the existing S69inet and S72inetsvc scripts.
Name the script with the S70 or S71 pre¿x. Scripts with the same pre¿xarerunin
some sequential way so it doesn’t matter if there is more than one script with the
same pre¿x.
See the README ¿le in the /etc/init.d directory for more information on
naming run control scripts.
I'm not sure if /etc/system can be used here, but you could also try to add your parameter to /etc/system.
Btw. SUN doesn't recommend changing udp_max_buf  -
Again from the Tuning Guide -
Changing the following parameters is not recommended unless there are extenuating circumstances that are described with each parameter. udp_max_buf
Do not change the value. If this parameter is set to a very large value, UDP socket applications can consume too much memory.  
Here is the book - http://dlc.sun.com/pdf/819-2724/819-2724.pdf
wmp

set it in /etc/system file

Dear All,
Thanks for your replies. I will check them out and will let you know.
I am changing the value as it is pre-requisite for Oracle RAC.

Thanks.