Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Analyzer captures own analysis traffic #122

Open
mossmann opened this issue Jul 11, 2024 · 2 comments
Open

Analyzer captures own analysis traffic #122

mossmann opened this issue Jul 11, 2024 · 2 comments

Comments

@mossmann
Copy link
Member

mossmann commented Jul 11, 2024

If Cynthion's CONTROL port is connected to the same hub as TARGET, CONTROL traffic is observed on TARGET, resulting in an infinite loop. This appears as many "invalid groups" in Packetry:

image

Note that adjacent USB ports on some computers are connected to an internal hub, so this can happen even when not using an external hub.

Workaround: Connect CONTROL to a USB port with a different host controller than the host port connected to TARGET. Most computers have more than one USB host controller. Typically ports that are physically distant from one another have separate host controllers. One way to be absolutely certain is to use two separate computers, one for CONTROL and one for TARGET.

Various solutions are possible, probably involving implementation of a capture filter in the analyzer gateware and some way to control it from within Packetry.

@mossmann
Copy link
Member Author

Even if we implement capture filtering to solve this problem, there would still be failures due to the bandwidth limitation when a high-throughput target device is being captured. We will always want to advise users to avoid this setup whenever possible, and we may want to try to detect the scenario and warn the user.

@martinling
Copy link
Member

I think this issue should be moved to the Cynthion repo. Any solution will need features in the analyzer first before we can support them in Packetry.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

2 participants