Symptoms
When the IP-DLC link service maintains an active Rapid Transport Protocol (RTP) connection for longer than 49 days and 17 hours, the service logs events that resemble the following:
Event ID: 2
Source: SNA IP-DLC Link Service
Description:
Invalid internal state detected
Filename: = file name
Line Number: = line number
FSM Address: = address
FSM State: = state
FSM Input: = input Systems Network Architecture (SNA) applications that connect to the IBM host system by using the IP-DLC link service are not affected when these events are logged.
Cause
The IP-DLC link service uses an internal 32-bit value for a millisecond timer that tracks the time that an RTP connection is active. The 32-bit value wraps (that is, it reaches its maximum value and then overflows and returns to its initial value) after 49 days and 17 hours. This causes the IP-DLC link service to try a path switch for the connection, even though there is no reason to do this. This triggers the IP-DLC link service events that are mentioned in the "Symptoms" section.
Resolution
Cumulative update information
The fix that resolves this problem is included in Cumulative Update package 9 for Host Integration Server 2010. For more information about how to obtain the cumulative update package, see Cumulative update package 9 for Host Integration Server 2010.
The fix that resolves this problem is also included in Cumulative Update 2 for Host Integration Server 2013 (KB2929767).
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.