Novell NetWare, Windows for Workgroups and ArcNet Cards

• Microsoft Windows for Workgroups version 3.1

SYMPTOMS

If you choose the Novell NetWare option in the Networks dialog box of Control Panel and you are using an ArcNet network interface card (NIC), you receive the following error message:

   The network Novell NetWare cannot be added because Windows for
   Workgroups does not support this network with your ArcNet adapter.

CAUSE

Using an ArcNet NIC to connect to your Novell NetWare network from a Windows for Workgroups workstation is not supported in the current version of Windows for Workgroups. This is because Windows for Workgroups and Novell NetWare handle ArcNet data packets somewhat differently.

MORE INFORMATION

Windows for Workgroups is implemented to fully support Novell NetWare connectivity. You can upgrade a Novell NetWare client workstation to a Windows for Workgroups workstation, or configure a Windows for Workgroups workstation to access a Novell NetWare server. Windows for Workgroups supports the Microsoft network transport protocol (NetBEUI) and the Novell network transport protocol (IPX) on the same network adapter card by including a Novell-compatible protocol, MSIPX.

MSIPX supports Token Ring and Ethernet MAC* header formats, but not token-passing bus network header formats, such as ArcNet. When you use an ArcNet NIC with Windows for Workgroups, the ArcNet NDIS (MAC-level) driver emulates Ethernet protocol and uses Ethernet header formats. That is how Windows for Workgroups recognizes data packets sent along the ArcNet network.

NOTE: *MAC is the Media Access Control layer, a sublayer of the data-link level in the OSI model. The MAC layer communicates directly with the network adapter card.

Novell NetWare's IPX protocol handles ArcNet data packets by "fragmenting" them at the sending end, and then reconstructing them at the receiver end. NetWare does this because ArcNet protocol creates packets that are smaller than the minimum size that NetWare protocol supports.

The problem occurs when you use an ArcNet card with Windows for Workgroups over a Novell NetWare network. The Novell network protocol expects to see a fragmented ArcNet data packet; however, since the ArcNet NDIS driver encapsulates data packets in an Ethernet-type header so that Windows for Workgroups can read them, the Novell NetWare network no longer recognizes them.