Resilient SIM in Ajax hubs

Resilient SIM is a feature that enables Ajax hubs with installed Ajax SIM to maintain stable cellular communication. In the event of data transmission failure, the feature allows the system to search for and connect to a more stable network. The Resilient SIM logic overrides the modem's default algorithm when the modem repeatedly connects to an unstable network.

System requirements

The Resilient SIM feature is available only for Ajax hubs with Ajax SIM installed and activated.

Ajax hubs running the following OS Malevich versions or later support the feature:

Ajax hubs not listed in the table above support the feature out of the box.

Operating principle

By default, most modems connect to an available network with a strong signal that has been used before. However, data transmission issues may arise on the network provider's side, even if the signal is strong. In such situations, the hub may lose internet connectivity via the cellular channel, while the modem still has a stable cellular connection.

The Resilient SIM feature allows Ajax hubs to switch from unstable networks to stay online. Once the connectivity issues are detected, the hub disconnects from the current network and searches for other available networks. Then, it connects to the one that provides stable data transmission, even if that network has a weaker signal or lower priority.

With Resilient SIM, the hub can:

• scan for available cellular networks and save a list of them;
• manage how the network is reselected after a connection failure.

The following connectivity issues activate the feature:

• The hub cannot connect to a cellular network.
• Cellular data service is available, but there is no internet access.
• The hub cannot establish a TCP/IP connection with the Ajax Cloud server.
• The hub switches between SIM cards.
• All previously scanned networks failed to connect.
• No available mobile networks are found during a manual scan.

Setting up the feature

The Resilient SIM feature is enabled for Ajax SIM by default. To ensure it operates correctly, follow the system configuration steps below.

Before setting up the feature, ensure Ajax SIM is installed in the hub and activated. Also, make sure the hub is added to the space and is currently online.

To configure the Resilient SIM feature, in an Ajax app:

1. Select a space and go to:

   • Devices → Hub → Settings → Cellular

2. In the Modem settings section, enable the following options:

   1. Cellular data

   2. Roaming

   3. Disable communication check with the operator

3. In the SIM cards section, select the SIM card slot in which the Ajax SIM card is installed.

4. Enter internet.gma.iot in the APN field.

5. Tap Back to apply the settings.