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

Insufficient MTU: 253. #219

Open
RoeeNadam opened this issue Jun 16, 2024 · 3 comments
Open

Insufficient MTU: 253. #219

RoeeNadam opened this issue Jun 16, 2024 · 3 comments

Comments

@RoeeNadam
Copy link

What can be the reason that I got this 253?
The write is successful but at a low rate of 0.3-0.4 kb/sec.

@dinesharjani
Copy link
Contributor

Hi @RoeeNadam - this is "standard behaviour" in a way.

Usually it means you set the MTU higher than is supported by the current device / connection, so you need to set it to the value given with the error (it's an enum with an associated value, if memory serves right). You can check how this is handled in ImageManager:

if case let McuMgrTransportError.insufficientMtu(newMtu) = error {

@everuribe
Copy link

I'm also seeing this error:
Request (SMPv2, group: image, seq: 120, command: upload) failed: Insufficient MTU: 505.

But our MTU is set to 512...

# RX/TX packet sizes
CONFIG_BT_BUF_ACL_RX_SIZE=512
CONFIG_BT_L2CAP_TX_MTU=512

@dinesharjani
Copy link
Contributor

@everuribe the error is in the logs, or DFU fails with this error? The error message might show up in the logs to "correct" the MTU down to the maximum length. As for that seven byte disparity, it could be many things. The McuMgrHeader is 7-8 bytes I think, could account for that, but don't hold me to it. Important thing: does DFU outright fail, or is it that you see this message on the logs? The latter is OK and expected behaviour.

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

3 participants