Hi, Michael. The steps you have available to you for cause identification and remediation of forwarding loss within the path visualization will depend on your level of access and control of the offending nodes, beyond simply modifying a ThousandEyes test's configuration.
Forwarding loss typically occurs by way of firewalls filtering packets based on protocol, port and/or packet characteristics (e.g., sequence numbers compared to connection states). Check out the following doc for a more detailed explanation:
Cisco ASA Breaks Path Visualization
Reconfiguring the test to utilize a different network protocol (e.g., ICMP instead of TCP) and/or probing mode (e.g., Force Syn instead of Prefer/Force SACK), along with setting the "Path Trace Mode" to be "In Session," could alleviate the forwarding loss. I encourage you to "play around" with the settings to get an idea of how network nodes might respond in the Path Visualization.
If you're still observing forwarding loss, after trying different test configurations, then feel free to contact our support team. We're available 24x7x365 and happy to perform live analysis/troubleshooting with you. Just click on the "Chat with Support" link, under the "Help and Support" menu at the top of your ThousandEyes portal page. You can also click the "Chat with Support" link in the bottom-right of the main login page.
More details about contacting ThousandEyes support can be found here:
ThousandEyes Chat: The Quickest Way to Get Support
Kindly,
Jeremy Stark
Technical Consulting Engineer
ThousandEyes (part of Cisco)
