Change the subnet mask for a SW200E Switch ?

That's actually my fault you can say - I suggested Tony to post the question on the Switch in the Brocade Forum to attract broader audience.
Thanks for your double clarifications
Cheers and Good night,
Sandip

i already gave you my take on making array/fabric changes in production in Clariion forum

Can I change it via the GUI interface or via a telnet session ?

Thanks

what fabric OS version are you running ? This is what the admin guide says:

When you change the Ethernet interface settings, open connections such as SSH or Telnet may be dropped. Reconnect using the new Ethernet ip information or change the Ethernet settings using a console session through the serial port to maintain your session through the change.

another note

Never change the IP address of the switch while two Telnet sessions are active. If you do, your next attempt to log in fails. To recover, gain access to the switch by one of these methods:

- You can use Web Tools and perform a fast boot. When the switch comes up, the Telnet
quota is cleared. (For instructions on performing a fast boot with Web Tools, see the Web
Tools Administrator¿s Guide.)

- If you have the required privileges, you can connect through the serial port, log in as root,
and use operating system commands to identify and kill the Telnet processes without
disrupting the fabric.


i personally like to maintain constant contact to my switch when i change settings, so that's why i prefer console ..but you have options.

I always did these kind of changes using telnet and as soon as the connection dropped, because of the ip change, I tried the new address. If it didn't work, I simply used the console. That always works

FC traffic is never interrupted during this change !