Knowledge Base

Net3193: A Virtual Circuit Error Occurred on the Session

Article ID: 110222

Article Last Modified on 9/30/2003

Microsoft LAN Manager 2.1 Standard Edition
Microsoft LAN Manager 2.1a
Microsoft LAN Manager 2.2 Standard Edition

This article was previously published under Q110222

SUMMARY

This error is common and most often indicates system conditions more than a specific problem:

NET3193: A virtual circuit error occurred on the session to SERVERNAME.
The NCB command and return code is the data.
96 18

The values translate as follows:

NCB = 96 = receive any
return code = 18 = session ended abnormally

MORE INFORMATION

In plain English this means that errors other than simple time-outs are preventing packets from reaching their destination. The command code, 96h for an NCB indicates that the failed command is: NCB.RECEIVE.ANY, No-Wait. Return code 18h indicates that the session ended abnormally or a time-out occurred.

In most cases this error indicates genuine interference with session traffic--conditions such as workstations being turned off without first logging off, load spikes that drive network usage too high, and physical network problems. Frequently, this error follows NCB time-outs on slow WANs (where time-outs are frequent) and net3100s on networks experiencing physical problems.

A network administrator looking for the source of the problem should first determine if the condition is isolated to one server or is occurring on all servers. It is common to see NET3193 errors scattered through an error log when a link to another network goes down or somebody shuts off a server without first logging it off. On large networks, where people tend to have lots of connections, the error is relatively common.

Depending on your protocol requirements, try increasing the configuration values of these PROTOCOL.INI parameters, in this order: DLCRETRIES, NETBIOSRETRIES, NETBIOSTIMEOUT.

Finally, Net3193 errors on a virtual circuit between a LAN Manager server and a Windows NT server (using NetBEUI) are also considered normal, indicating autodisconnection of the session to an NT server. To reduce these symptoms, increase the AUTODISCONNECT value on the NT server. See article WIN_NT 109555 for more information.

Additional query words: Net error log neterror errorlog 2.10 2.1 2.1a 2.10a 2.20 2.2

Keywords: KB110222