Q140007: WFW Direct Hosting over ODI Drivers Drop Network Connections
Article: Q140007
Product(s): Windows for Workgroups and Windows NT Networking Issues
Version(s): WINDOWS:3.11; winnt:3.5,3.51
Operating System(s):
Keyword(s):
Last Modified: 08-AUG-2001
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The information in this article applies to:
- Microsoft Windows NT Workstation versions 3.5, 3.51
- Microsoft Windows NT Server versions 3.5, 3.51
- Microsoft Windows for Workgroups version 3.11
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SUMMARY
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A Windows for Workgroups 3.11 client, running IPX and connecting to an Windows
NT version 3.5 or 3.51 Server or Workstation by default uses direct hosting.
Direct hosting is a method of bypassing the NetBIOS layer and sending
client/server messages (SMBs) directly over the transport, in this case, IPX.
If the Windows for Workgroups 3.11 client is using an Open Datalink Interface
(ODI) driver rather than an NDIS driver, the client may drop packets from the
server and lose the connection.
This is most evident where you have large file reads and a fast server.
MORE INFORMATION
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You may be able to improve the connection reliability by not using direct
hosting from client to server. This forces NetBIOS to manage the session, rather
than making the redirector manage retransmissions. To turn direct hosting off at
the client, add the following parameter to the [network] section of system.ini:
directhost=no
Note: Page 4-12 of the "Windows for Workgroups Resource Kit", Addendum for
Version 3.11 incorrectly states this parameter as 'directhosting'. This is a
documentation error.
Additionally, you must install the IPX/SPX Compatible Transport with NetBIOS on
the Windows for Workgroups client.
When you turn direct hosting off, large file read requests from the client are
requested in a read block raw SMB, and the data is transferred over the NetBIOS
session. The following trace shows at frame 20, the client initiates a read
block raw, and the data is returned by the server over the NetBIOS session:
# DeltaT Src MAC Dst MAC Protocol Description
20 0.004 WFW Client NT server SMB C read block raw, FID = 0x800,
Read 0xfe00 at
21 0.147 NT server WFW Client NBIPX Session Data
22 0.001 NT server WFW Client NBIPX Session Data, Send Seq 0x0C,
Offset 0x5AC
23 0.002 WFW Client NT server NBIPX Session Data, Ack, Recv Seq
0x0D, 0x10 Bytes Received
24 0.002 NT server WFW Client NBIPX Session Data
25 0.002 NT server WFW Client NBIPX Session Data
26 0.001 NT server WFW Client NBIPX Session Data, Send Seq 0x0F,
Offset 0x16B0
27 0.002 WFW Client NT server NBIPX Session Data, Ack, Recv Seq
0x10, 0x13 Bytes Received
If direct hosting is on, then the redirector initiates a read block multiplex,
and the data is sent back in read block multiplex response SMBs, directly over
IPX. The following trace shows a read block multiplex coming from the client at
frame 19. Frames 20 through 29 show the server responding with read block
multiplex responses, and frame 30 is another read block multiplex command from
the client:
# DeltaT Src MAC Dst MAC Protocol Description
19 0.005 WFW Client NT server SMB C read block mpx, FID = 0x800,
Read 0x3750 at 0x00000000
20 0.003 NT server WFW Client SMB R read block mpx, Read 0x588 of
0x3750
21 0.006 NT server WFW Client SMB R read block mpx, Read 0x588 of
0x3750
22 0.001 NT server WFW Client SMB R read block mpx, Read 0x588 of
0x3750
23 0.002 NT server WFW Client SMB R read block mpx, Read 0x588 of
0x3750
24 0.002 NT server WFW Client SMB R read block mpx, Read 0x588 of
0x3750
25 0.001 NT server WFW Client SMB R read block mpx, Read 0x588 of
0x3750
26 0.001 NT server WFW Client SMB R read block mpx, Read 0x588 of
0x3750
27 0.002 NT server WFW Client SMB R read block mpx, Read 0x588 of
0x3750
28 0.001 NT server WFW Client SMB R read block mpx, Read 0x588 of
0x3750
29 0.001 NT server WFW Client SMB R read block mpx, Read 0x588 of
0x3750
30 0.004 WFW Client NT server SMB C read block mpx, FID = 0x800,
Read 0x3750 at 0x00003750
In this case, the redirector is responsible for requesting resends of lost
packets in either direction. This may be too much of a burden on the Windows for
Workgroups redirector which is running over an ODI driver. The extra layer
needed to map NDIS 3.0 protocols to an ODI NIC driver (MSODISUP.386) may also
contribute to the problem, as running direct hosting over NDIS drivers does not
seem to exhibit this problem.
Additional query words: prodnt 3.11 3.50 3.51 directhost directhosting
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Keywords :
Technology : kbWinNTsearch kbWinNTWsearch kbWinNT351search kbWinNT350search kbWinNTW350 kbWinNTW350search kbWinNTW351search kbWinNTW351 kbWinNTSsearch kbWinNTS351 kbWinNTS350 kbWinNTS351search kbWinNTS350search kbAudDeveloper kbWFWSearch kbWFW311
Version : WINDOWS:3.11; winnt:3.5,3.51
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