MSDLC32 May Not Receive All Packets in Heavy Traffic

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Article ID: 156149 - View products that this article applies to.
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SYMPTOMS

Programs using the Microsoft 32-bit DLC protocol may not be able to connect to the host over the network, especially when first starting up.

CAUSE

If the client receives a large number of DLC packets in an extremely short period of time, the MSDLC32 protocol may be unable to dynamically allocate additional buffers quickly enough to successfully receive all incoming packets.

STATUS

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 http://www.microsoft.com/windows.

MORE INFORMATION

When MSDLC32 initializes, it allocates a certain number of buffers (specifically, Read CCB2 buffers) for incoming DLC packets. Over time, as additional buffers are needed, they are allocated dynamically. In the original release of MSDLC32, the initial number of Read CCB2 buffers allocated is 16. In this update, that number is increased to 64. By allocating more buffers initially, the buffers are available to be used immediately, 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 with multiple routes to each host. In such environments, a very large number of packets may be received by the client nearly simultaneously in response to a single query. Under such high-stress situations, packets could be dropped 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 usage to be sufficient to accommodate surges in received packets.

Properties

Article ID: 156149 - Last Review: October 1, 2013 - Revision: 2.2
APPLIES TO
  • Microsoft Host Integration Server 2000 Standard Edition
  • Microsoft Windows 95
Keywords: 
kbnosurvey kbarchive kbapi kbnetwork kbpolicy kbprb KB156149

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