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Cisco Meraki Documentation

APN Selection

To initiate a data session with a cellular service provider network, the MG requires an Access Point Name (APN). There are three distinct methods through which an APN can be configured on the modem:

  1. APN loaded by modem firmware
  2. Manually configure an APN via Dashboard or the local status page
  3. Created using the AutoAPN process

Some modem vendors provide specific modem firmware tailored to major service providers, for example Verizon or AT&T. The modem detects the SIM card and identifies the carrier associated with the SIM card during boot-up. The modem then loads the corresponding firmware required by that carrier. The firmware linked to major service providers includes an APN repository specific to those carriers. 

For instance, Verizon firmware loads the 'vzwinternet' APN, while AT&T firmware loads the 'broadband' APN. By default, the host platform should utilize these APNs to establish the data session when operating on the networks of these specific service providers. This ensures seamless compatibility and optimal performance in alignment with the service provider's network configurations.

Some customers opt to use a custom created APN. This usually happens when they want to use a custom APN other than the generic APN associated with a service provider.  This could be to restrict inbound access to devices behind a firewall with a virtual private network (VPN) to route traffic through VPN tunnel, or to create a second layer of data encryption. Users can configure this APN via Dashboard or on the Local Status Page. 

Click on the "Uplink" tab of the MG and scroll down to the "Configuration" section. Click on the "edit" button as shown:

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edit_sim.png

The configurable fields are explained below:

  • Name - This field is used to configure the APN provided by the carrier.
  • IP type - This field is used to specify the preferred IP type when connecting to the APN. The different options are IPv4, IPv6 and IPv4v6.

  • Authentication - Select the authentication method the MG uses to establish a successful connection, if needed. The different options are PAP (Password Authentication Protocol), CHAP (Challenge Handshake Authentication Protocol) and None.

  • Username - This field is used to specify the username when authentication is set to PAP or CHAP.

  • Password -  This field is used to specify the password when authentication is set to PAP or CHAP.

Note: If incorrect information is entered for any or all of the parameters mentioned above, this will prevent a data session from establishing over the cellular network. As a result the MG will be unable to connect to the carrier's network.

Once you open the local status page of the MG, click on the “Configure” tab. In the "Cellular Settings" section, check the checkbox for “Override SIM1 data session setting” (if active SIM slot is SIM1) or “Override SIM2 data session setting“ (if active SIM slot is SIM2). An example for "Override SIM1 data session setting" selected is shown here:

LSP_cellular.png

The configurable fields are explained below:

  • APN Name - This field is used to configure the APN provided by the carrier.

  • IP Type - This field is used to specify the preferred IP type when connecting to the APN. The different options are IPv4, IPv6 and IPv4v6.

  • Authentication - Select the authentication method the MG uses to establish a successful connection, if needed. The different options are PAP (Password Authentication Protocol), CHAP (Challenge Handshake Authentication Protocol) and None.

  • Username - This field is used to specify the username when authentication is set to PAP or CHAP.

  • Password -  This field is used to specify the password when authentication is set to PAP or CHAP.

Note: If incorrect information is entered for any or all of the parameters mentioned above, this will prevent a data session from establishing over the cellular network. As a result the MG will be unable to connect to the carrier's network.

With the exception of a few major carriers, most carriers lack a dedicated modem firmware for their cellular network. When the modem identifies a SIM card from one of these carriers, the modem loads a generic firmware to facilitate compatibility and connectivity. Generic firmware does not have any default APNs in its repository. This is when the “AutoAPN Management Process” will create a data APN based on an algorithm.

APN FAQ   

How does the MG determine which APN to use?

The default MG behavior when first powered on is to scan the SIM card, determine from the scan which carrier APN could be used, and then initiate a connection. The APN assumed is based on a combination of SIM card and operator MCC (Mobile Country Code) and MNC (Mobile Network Code). From this combination, the MG selects that APN from the firmware APN list as mentioned in APN Loaded by Modem Firmware or creates an APN as described in APN Created by AutoAPN Process.

Subscribers who opt for a static IP APN, often referred to as a private APN, usually need to manually adjust the settings on the local status page. Most carriers do not permit the use of both a private APN and a dynamic APN concurrently for their service plans. Consequently, users must configure the appropriate bearer parameters, including the APN and username/password, to ensure connectivity as explained in Configured Manually, Failure to adhere to these bearer requirements may result in the device being unable to access the cellular network, particularly if an incorrect APN is entered.

 

Will the MG test connectivity from the APN list and the override?

No, once the override settings are configured on the local status page, the MG will only use the override configurations. There is no logic in the firmware at this time to fallback if the local status page configuration is incorrect. We recommend users test and validate configurations by checking for connectivity after configuring overrides.

 

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