MSDLC32 May Not Receive All Packets in Heavy Traffic

This article was previously published under Q156149
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Programs using the Microsoft 32-bit DLC protocol may not be able toconnect to the host over the network, especially when first starting up.
If the client receives a large number of DLC packets in an extremelyshort period of time, the MSDLC32 protocol may be unable to dynamicallyallocate additional buffers quickly enough to successfully receive allincoming packets.
This problem no longer occurs in Windows 98. To resolve this problem, install the current version of Windows. For information about the current version of Windows, visit
When MSDLC32 initializes, it allocates a certain number of buffers(specifically, Read CCB2 buffers) for incoming DLC packets. Over time, asadditional buffers are needed, they are allocated dynamically. In theoriginal release of MSDLC32, the initial number of Read CCB2 buffersallocated is 16. In this update, that number is increased to 64. Byallocating more buffers initially, the buffers are available to be usedimmediately, without the delay incurred with dynamic allocation.Additional buffers are dynamically allocated later as needed.

This problem may occur in an environment using multiple DLC hosts withmultiple routes to each host. In such environments, a very large numberof packets may be received by the client nearly simultaneously in responseto a single query. Under such high-stress situations, packets could bedropped during the time new buffers are being allocated to receive them.

This problem is more likely to occur when first starting a DLC session,because the buffer pool typically grows during the course of normal usageto be sufficient to accommodate surges in received packets.
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Article ID: 156149 - Last Review: 10/01/2013 04:35:08 - Revision: 2.2

Microsoft Host Integration Server 2000 Standard Edition, Microsoft Windows 95

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