COSA database overview and frequently asked questions
The Country and Operator Settings Asset (COSA) database is used by mobile operators (MOs) to provision Windows devices for mobile broadband.
To see a list of available settings MOs can configure in desktop COSA, see Desktop COSA database settings.
Here are some frequently asked questions about COSA:
What are the settings that mobile operators can specify in COSA?
For details, see the tables in Desktop COSA database settings.
What events trigger the application of new mobile operator settings?
These events trigger the Windows provisioning engine to look for a change in settings:
- When there's an insertion or removal of a physical SIM (change in ICCID)
- When an eSIM (change in ICCID) is reconfigured
- When the device boots
What SIM information from modems does COSA use?
For MO/MVNO discovery, Windows tries to make the best match for an available profile in the COSA database using identifiers such as MCC / MNC, ICCID, IMSI, SPN, GID1 from the SIM in the modem.
What is a COSA profile?
The COSA database consists of profiles. Each profile contains a set of cellular provisioning rules applied to a device, like APN and MO branding information to be displayed in the Windows UX. Each profile also has a set of targets, matching a cellular device to a set of cellular provisioning rules. Each MO has their own COSA profile, but some MOs have multiple profiles for specific use cases (like implementing a 5G private network or an eSIM provisioning profile).
How does a COSA profile get matched to a device?
Each COSA profile contains a set of targets used by Windows to match the profile to the device. MOs can set which target identifiers they'd like to use. Valid target identifiers are: MNC, MCC, SPN, PNN, GID1, ICCID, IMSI. Windows looks for the profile with the highest number of target identifiers to use. If Windows detects that the device's SIM matches with one identifier (SPN) from COSA profile A, but two identifiers from COSA profile B (SPN and ICCID), Windows utilizes the COSA profile A.
Can OEMs customize COSA?
Microsoft strongly encourages mobile operators to update the central database via the MO Configuration Portal. However, there are some scenarios where an OEM customization of COSA might be more suitable for their devices or manufacturing timelines. OEMs can extend COSA to meet their needs. Windows prioritizes the OEM customization. For more information on OEM customizations of COSA, see Customize the Country and Operator Settings Asset.
OEMs can, in some cases, make modifications to COSA on behalf of an MO. See the Mobile operator configuration portal guide.
Is there an algorithm to make the best APN match?
In versions of Windows before Windows 10, version 1703, MOs could specify an autoconnect order. Windows 10, version 1703 and later continue to use a round-robin approach through all available APNs, but there's no longer a specific order that the algorithm uses.
Where is the COSA database stored and can it be visually inspected?
COSA is in the format of a Windows provisioning package (.ppkg). It is in the Windows\Provisioning\COSA\Microsoft folder. You can use a non-Microsoft tool, such as 7-Zip File Manager, to visually inspect its contents.
Extensions to COSA, if specified in the device image, are in the COSA\OEM folder. For more information, see Customize the Country and Operator Settings Asset.
Are custom or manually created APNs migrated to the COSA database?
When you upgrade to Windows 10, version 1703 or later, COSA replaces apndatabase.xml after the upgrade. If an APN was provisioned in the previous version, whether custom, manual, or device-provisioned via the database, the APN is migrated as a part of the upgrade to version 1703 and the device continues to use it for connectivity without requiring any further action.
Do custom or manually created APNs still have priority over the defaults from the database?
When you upgrade to Windows 10, version 1703 or later, manually provisioned APNs still have priority over the defaults from the database just as they did in version 1607 and earlier.
Why does the "Set as metered connection" setting sometimes change from Off to On?
Updates to the Windows operating system might include updates to the COSA database. If the database is updated, the provisioning engine might remove the cellular profiles. When the system restarts after database updates are installed, the provisioning engine reinstalls the cellular profiles. This operation resets user settings to their default values. For example, Set as metered connection changes from Off to On. This behavior is by design.