After configuring CAM to use TCP, the port multiplexer (csampmux) service hangs periodically, resulting in various product stability and performance problems.

Document ID : KB000097127
Last Modified Date : 01/08/2018
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Issue:
In your environment, CAM is configured to communicate via TCP communication, and you are experiencing the following symptoms:
- Unable to open new DSM Explorer windows. 
- Existing DSM Explorer windows are marked, "not responding" by Windows. 
- CAM has high CPU and very high memory usage. 
- Other processes with high memory usage: ccsmactd.exe, rcMansrv.exe, SD_Taskm.exe, cmEngine.exe, etc. 
- Instman process is stopped (SD_Taskm.exe) 
- Unable to retrieve a "camstat -a" output, with busy/no reply error from CAM.
- Unable to stop and restart the CAM or CA Connection Broker (csampmux) service.
- The csam.log file contains recurring messages: 
serviceMain: - listener (port no. 4105) - did not respond to accept within timeout period of 5 seconds 
- Killing csampmux.exe seems to resolve the problem temporarily.
- In some cases both cam.exe and csampmux.exe are unable to be killed by Windows Task Manager.
Environment:
Client Automation (ITCM) -- r14 SP1, SP2
Cause:
When CAM is configured to use TCP for messaging, a listener on the CSAM port multiplexer is configured to intercept and re-transmit the traffic.  When CSAM receives TCP traffic destined for CAM, it has a short timeout window in which it expects the local CAM service to accept and acknowledge the incoming connection.  If CAM does not respond within 5 seconds, it will cause CSAM to deregister the CAM service, therefore discontinuing TCP message communication, which will cause product instability.
Resolution:
1- Apply the following product patch, which will update the algorithm for de-registering and re-registering the listener for CAM traffic within the CSAM component:
T55L084 (CAM RESPONDS AFTER PMUX KILLED)

Note: Patch T55L084 is compatible with ITCM r14 SP1 and SP2 releases, only.

2- If using Windows Server 2008 R2 SP1, the following Microsoft KB patch must be applied (KB4338821):
https://support.microsoft.com/en-us/help/4338821/july242018kb4338821osbuildpreviewofmonthlyrollup