Forum Discussion
TLS handshake failure between IoT product and AWS
- 6 years ago
Just adding an update for closure on this thread...
In the end, the problem was corruption of the TLS handshake caused by a default buffer size in Microchip's TCP/IP library being too small. I haven't completely studied the cause yet, but it appears that traffic received via a HughesNet link uses a larger than typical MTU setting or something along those lines. Simply resizing that buffer made the problem disappear.
Patrick
I can't rule that out, of course, but it doesn't feel like a timeout problem. I simulated a network connection with 2,500ms latency and the TLS handshake completed normally over a landline internet connection. I also added an arbitrary 15 second delay between TLS handshake steps, and the handshake completed normally despite taking a very long time to finish. When our device tries to connect to AWS over a HughesNet connection, the steps that lead up to the missing packet don't take any longer than expected, aside from the overhead of the latency inherent to the link.
I'm just beginning a conversation with an engineer at HughesNet, and I'll ask about the possibility of a timing problem if we don't head down a more likely path first. Thanks for continuing to add ideas to the mix...
Patrick
Just adding an update for closure on this thread...
In the end, the problem was corruption of the TLS handshake caused by a default buffer size in Microchip's TCP/IP library being too small. I haven't completely studied the cause yet, but it appears that traffic received via a HughesNet link uses a larger than typical MTU setting or something along those lines. Simply resizing that buffer made the problem disappear.
Patrick
- Liz6 years agoModerator
Good morning Patrick,
Thanks so much for updating us here in your thread, sounds good. I'm glad you were able to figure things out with our engineers! If you ever need anything else, please don't hesitate to reach out again!
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