We use a service to route calls for our call center. There are about 100 call center agents and everyday, four or five will have trouble launching the soft phone application. We connect to the call manager and soft phone system via and MPLS.
Sometimes restarting the PC fixes it. Sometimes resetting the browser fixes it, sometimes disabling / re-enabling the NIC fixes it. Sometimes it magically fixes itself.
The attached packet capture image from Wireshark typifies what a TCP stream looks like from a PC experiencing a failed application launch.
NOTE: In the attached file, the TCP RST flag is not always seen. Many times I only see the TCP re-transmissions or TCP SEQ Out Of Order.
Questions 1: Am I right to believe my problem is, either a reset is being thrown or the other side stops responding for some reason, hense the re-transmissions
Since this is over an MPLS, I am not able to get a capture from the other side.
Question 1. What troubleshooting steps should I take to identify why I am getting these re-transmission, and or Resets.
Question 2: Is it possible that some traffic might be routing out the MPLS, while other is getting lost in the network? If this were possible, and I wanted to capture the packets on the Switch, would I SPAN the both the interface connected to the PC and the Interface connected to the router, or just the router?
Note: I don't have trouble logging into the portal, I have trouble launching the softphone, which uses a browser extension.
Note: We connect to the portal (user authentication and call manager) and establish the soft phone connection over the MPLS.
Note: When the problem is active, it affects all browsers, so switching browsers does not help..