Large Number of DAP (Data Access Pack) TCP Sockets have CLOSE_WAIT Status
Last updated on APRIL 04, 2018
Applies to:
Oracle Communications Network Charging and Control - Version 5.0.0 to 5.0.1 [Release 5.0]Information in this document applies to any platform.
Symptoms
The Data Access Pack (DAP) application is not closing down its TCP port connections which are left in CLOSE_WAIT state. These TCP ports remain in the CLOSE_WAIT state and are not cleared out and accumulate over time.
Example of problem scenario:
Setup:
- DAP communicating with a remote system on port 8001
- The remote system timeout on inactive port is 30 seconds, before sending out a TCP FIN message to DAP
- persistentConnectionCheckTimeout parameter set, as per <note 1513094.1>
1. DAP establishes a connection
2. DAP message is sent out, the message is sent successfully
TCP connection Status:
Fri Apr 5 12:43:28 GMT 2013
10.48.42.137.48462 10.48.42.138.8001 130880 0 139264 0 ESTABLISHED
10.48.42.137.40669 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
10.48.42.137.60438 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
10.48.42.137.35789 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
10.48.42.137.41044 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
10.48.42.137.34035 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
10.48.42.137.45899 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
3. After 30 seconds inactivity, the remote server decides to close the TCP connection and initiates the TCP disconnection procedure to DAP
4. DAP gets the fin and turns its TCP port into CLOSE-WAIT
TCP connection status:
Fri Apr 5 12:44:02 GMT 2013
10.48.42.137.48462 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
10.48.42.137.40669 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
10.48.42.137.60438 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
10.48.42.137.35789 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
10.48.42.137.41044 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
10.48.42.137.34035 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
10.48.42.137.45899 10.48.42.138.8001 130880 0 139264 0 CLOSE_WAIT
5. After 30 seconds, the TCP scoket is still in CLOSE_WAIT and is still not cleared out.
The CLOSE_WAIT state is temporary and should only remain for a split second, between the first FIN and the last ACK, but remains forever.
Cause
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