Standard operating procedure on TCP/IP network is to drop and reconnect. However, it should be transparent to the user as access to network share is supposed to be instant.
A – are you using AD (Active Directory) which presupposes DNS? Delay in reconnect could be lookup problems – holdover ‘netbios’/WINS processes.
B – IPX still running? Broadcast traffic under control?
C – Check the binding order of protocols on the network adapters. If Client for netware is first then it has to time out before the client for microsoft talks to the 2k3 server which ignored the netware client.
D – are all your clients W2k / XP then clean up your authentications.