Named Pipes

This section describes limitations and problems involving the use of named pipes in Windows NT 3.5.

To upgrade from Windows for Workgroups to Windows NT 3.5, installing IPX/SPX protocol in addition to NetBEUI protocol, you need to install a new VREDIR.386, which is available on the Windows NT Server CD in \clients\wfw\update\vredir.386.

Make sure the default frame type is correct. It has been changed from ethernet_802.3 to ethernet_802.2. If you are using 802.3, you need to change the following entry in the protocol.ini under the [nwlink] section:

FRAME=ETHERNET_802.3

Windows NT Server 3.5 can support a maximum of 512 named pipes. Each SNA Server client uses two named pipes, so you can run out of SMB server resources at around 250 clients if you are using named pipes as the transport. The 20xx events in the Event Log typically result from SMB running out of these MaxWorkItem resources.

The maximum is raised to 4096 in Windows NT Server 3.51, and the SNA Server 2.11 automatically sets this entry to 4096. The default is still set to 512 if you are running SNA Server 2.1 on Windows NT 3.51, so you'll have to manually change this parameter. There are some other improvements in SNA Server 2.11, including not having to log on twice, so you should upgrade to it.

It would be a good idea to switch to sockets from named pipes for several reasons:

• • TCP/IP or IPX connections don't have the resource limitation described here
• • You can get up to a 30 percent improvement in performance
• • Negotiating a session with sockets takes one third less traffic on the network compared to using named pipes
• • Named pipes consume quite a bit more memory on the server