Mapped drive problem

I map shared folder on windows server 2012 from my xp and 7 machine.
Problem is that after some short time about 15 minutes of idle my connection
drop ,I can access to mapped drive with double click of mouse but there is
delay about 30 seconds to access to resources.<o:p></o:p>

<o:p> </o:p>

I would like to access to resources to be immediately ,with no delay.<o:p></o:p>

Since now i tried:

On client side(on xp and 7) makingReg_DwordKeePConn withffffffffon

HKLM\SYSTEM\CurrentControlSet\Service\lanmanworkstation\parameters

And

Network security: LAN Manager authentication level

The policy is:

Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options\Network security: LAN Manager authentication level

Please change “Send LM & NTLM - use NTLMv2 session security if negotiated”.

And on server side on windows server 2012 with command:

net config server /autodisconnect:-1