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Cisco Bug: CSCup16651 - Max TCP connections reached on SIP CIPC resulting in delayed responses

Last Modified

Jul 08, 2019

Products (1)

  • Cisco IP Communicator

Known Affected Releases

8.6(3) 8.6(4)

Description (partial)

When using CIPC SIP with a CallManager Group that has more than 1 node, and one of those nodes happens to be down, CIPC will exhaust all TCP connections attempting to connect to that node resulting in delayed responses to the node it is registered to.

The delay can be anywhere from 6-30 seconds.  This can cause call drops, hold and unhold failures, CIPC un-registering, and other issues.

The traces will show the following right after the delay when CIPC finally responds.

Mon Jun 02 15:46:05.379 : ERROR : (  4616) SIP : sip_tcp_create_connection : socket connect failed errno: 9 ipaddr:, port: 5060
Mon Jun 02 15:46:05.379 : ERROR : (  4616) SIP : sip_tcp_detach_socket : Max TCP connections reached.
Mon Jun 02 15:46:05.379 :   DET : (  4616) SIPCC-SIP_TCP_MSG: sip_tcp_purge_entry: Socket fd: 2996 closed for connid 1 with address: 1, remote port: 180994258
Mon Jun 02 15:46:05.379 : ERROR : (  4616) SIP : sip_transport_setup_cc_conn : DN :tcp channel create error server addr=, server port=5060) failed.

Sniffer captures will show that the SIP packet arrive in time, however CIPC delays processing it.

CIPC using SIP with one or more nodes in the CCM Group down.
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