[SRU] network-manager can’t modify MTU automatically based on what ModemManager exposes for WWAN modems.

The .debdiff file “network-manager_1-1.22.10-1ubuntu2.3-focal.debdiff” is attached for focal(20.04).

The attachment ".debdiff for focal" seems to be a debdiff. The ubuntu-sponsors team has been subscribed to the bug report so that they can review and hopefully sponsor the debdiff. If the attachment isn't a patch, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are member of the ~ubuntu-sponsors, unsubscribe the team.

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Status changed to 'Confirmed' because the bug affects multiple users.

Hey Jerry! This looks good and I can certainly sponsor it for you.

One question before I do that though. Looking at the original source commit:
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/499?commit_id=212758ea05a4c13d65f36b55c90aee7919642631
It is mentioned there by some user that MM can also expose this via MTU from the IPv6 bearer, not only IPv4. Not sure if this is an use case we are concerned about, and if there was a follow up patch for this use case.
Can you take a look and give me a sign if we should still continue as-is? Thanks!

Hi Lukasz,

Carrier network providers use bearer information to carry the MTU setting, this can be received by the modem then exposed to its host system either via NetworkManager's ipv4_config or ipv6_config.

I think ipv4_config is the must supported setting in carrier's network, that may be why this upstream patch has not considered ipv6_config. (MTU should be the same(per device) for both ipv4 and ipv6)

Our customer has used this patch in the field testing and this patch worked as expected.
There should be no concern to get MTU only via ipv4_config.

Thanks for highlight this question.

Sponsored the change, it should now be in the focal Unapproved queue, waiting from someone from the SRU team to review and accept. I also pushed the change to the git repository.

Hello Jerry, or anyone else affected,

Accepted network-manager into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/network-manager/1.22.10-1ubuntu2.3 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-focal. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

Test passed with Lenovo ThinkEdge SE30(11ND) on Focal:
   * The version of the packages tested:
     network-manager: 1.22.10-1ubuntu2. 3

The detail testing procedure and result is provided as the attached file : "SRU for network-manager(verify report).pdf"

The verification of the Stable Release Update for network-manager has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

This bug was fixed in the package network-manager - 1.22.10-1ubuntu2.3

---------------
network-manager (1.22.10-1ubuntu2.3) focal; urgency=medium

  * wwan: Set MTU based on what ModemManager exposes
    (LP: #1955797)

 -- Jerry Lee <email address hidden> Mon, 27 Nov 2021 09:37:06 +0800