APN Editor: Issues with 'Same APN as for Internet' checkbox

[Tony Espy]

ofono on Ubuntu currently supports three distinct APN types:
 * Internet
 * MMS
 * Combined Internet/MMS

The value of the 'Type' property for Internet and MMS is just lower-cased versions of each. A combined Internet/MMS APN is of type 'internet', but has the additional MMS properties 'MessageCenter' and 'MessageProxy'. Here's an example for ATT:

[context1]
Name=ATT Phone
AccessPointName=phone
Username=
Password=
Type=internet
Protocol=ip
MessageProxy=proxy.mobile.att.net:80
MessageCenter=http://mmsc.mobile.att.net

The current APN Editor doesn't allow a user any way to view the current MessageCenter ( aka MMSC ) or MessageProxy ( aka Proxy & Port ) of an existing APN ( ie. provisioned by ofono ). There's a bit of overlap with bug #1388222. The only way a user can even tell that an APN is combined currently is if the APN is active; in this case the "Same APN as for Internet" will show a checkmark.

<https://wiki.ubuntu.com/Networking#apn-mobile>: "Choosing an item should open the corresponding dialog."

Also, there's no way for a user to extend an existing APN by adding MMS parameters to it. The Networking specification states that the "Same APN as for Internet" should be on the Custom MMS page, but it's currently a list item in the MMS APN list.

Futhermore, if the checkbox were to move to the Custom MMS page, it could only be used in the existing model if there was an active Internet APN. Finally, the editor would need to ensure that it added the new attributes to the existing Internet APN vs. creating a brand new Custom MMS APN. If the checkmark moves, then it makes it hard to identify combined APNs from the top-level lists ( see above ).

<https://wiki.ubuntu.com/Networking#apn-mobile>: "“Internet APN” should include the suggestion “Copy from MMS APN”."

Finally, we also will need to protect against a user selecting a Custom MMS APN when the current active Internet APN already supports MMS. This would lead to undefined behavior.

This bug is being reported against vivid-devel on mako, image #136, but also exists in RTM.

[Launchpad Janitor (janitor)]

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

[Matthew Paul Thomas (mpt)]

"Futhermore, if the checkbox were to move to the Custom MMS page, it could only be used in the existing model if there was an active Internet APN."

Why would this be a problem? If your current Internet APN settings aren't working, what would be the point of copying them to MMS APN settings?

"If the checkmark moves, then it makes it hard to identify combined APNs from the top-level lists"

What is a "combined APN"?

"we also will need to protect against a user selecting a Custom MMS APN when the current active Internet APN already supports MMS"

How would you know whether the active Internet APN also works for MMS? Do you automatically try activating one when the user asks to activate the other?

[Matthew Paul Thomas (mpt)]

Sorry, I misread the description. If I understand correctly:
- MMS APN settings are a superset of the Internet APN settings, but the common settings might have all the same values.
- If they are the same, you might achieve this by typing them all twice, or by copying and pasting between them, or by choosing a database entry that is specifically targeted at both.
- This dual-purpose database entry is what Ofono calls a "combined APN".

I guess that, as with anything else in the database, a combined APN might be wrong -- and one of the ways it could be wrong is that it's correct for one data type but incorrect for the other.

[Matthew Paul Thomas (mpt)]

Specification updated. <https://wiki.ubuntu.com/Networking?action=diff&rev2=262&rev1=260>

[Sebastien Bacher (seb128)]

is that still an issue with the new UI? that option seems to have been removed