WFWG NetBEUI Differences Running on Token Ring Network

• Microsoft Windows for Workgroups version 3.11

SUMMARY

When Windows for Workgroups connects to a share over a token ring network, it sends out a Name Query with different token ring information over NetBEUI, depending on whether the protected mode version or real mode version was started.

MORE INFORMATION

When Windows for Workgroups connects to a file/print share or runs a named pipe application, a Name Query is sent out multiple times on the network to find the server it is being connected to. Under Windows for Workgroups version 3.11, the protected mode version of NetBEUI first sends out three Name Queries without the routing information field (RIF), and if no response is received, it sends out three more Name Queries with the RIF. This allows the workstation to work in token ring networks that include transparent bridges or source route bridges.

The real mode version of NetBEUI sends out up to six Name Queries, all with the RIF. This allows the workstation to work properly in a network with source route bridges, but does not allow it to connect to servers on different rings when only transparent bridges are installed.

A transparent bridge, by definition, copies all frames without an RIF from one ring to another without any additional filtering. Most transparent bridges in use today "learn" which network stations are on each ring attached to it and do not copy a frame onto its other rings if the location of the receiving station is known.

A source route bridge only copies frames containing an RIF. If the packet is a discovery packet such as a NetBIOS Name Query, the "all routes" broadcast indicator is turned on and each bridge copies the frame to all rings it is connected to. Once the ring/bridge information has been filled in, source route bridges only consider forwarding packets that contain its bridge number. In addition, these packets will only be forwarded on to rings designated in the RIF. This filtering works to cut down the amount of unnecessary network traffic on each ring.

There is a third bridge type called a source route transparent (SRT) bridge, which is a combination of the two types defined above. SRT bridges copy all frames without an RIF, with an RIF and the "all routes" broadcast indicator on, or if the RIF of the frame contains the number of the bridge examining the frame.

There was a problem with Windows for Workgroups workstations running the protected mode version of NetBEUI connecting to Windows NT or Windows NT Advanced Server systems in a network containing SRT bridges. The problem was with NetBEUI on Windows NT and Windows NT Advanced Server and has been resolved in Windows NT Service Pack 2. The problem occurs when a Windows for Workgroups workstation using protected mode NetBEUI is connecting to a server across an SRT bridge and sends the Name Query without the RIF. The Windows NT server responds to the client with the RIF included in the frame. From then on, the Windows for Workgroups workstation continues to use the RIF, and the server, incorrectly, does not.

Additional query words: wfw wfwg 3.11

Keywords : nttcp
Version : 3.11
Platform : WINDOWS
Issue type :