In a public cellular network infrastructure, cellular carriers tend to implement timeouts at the application level and allow base stations to decide how they want to service users with different traffic loads. Hence, maintaining a reliable cellular network connection is a constant challenge for industrial M2M applications, especially for mission-critical applications such as real-time remote monitoring of power grids, pipelines, and traffic control centers. Moxa's OnCell products come with GuaranLink support for continuous and reliable cellular connectivity, which translates to on-demand cellular communication and zero data loss in your cellular network.

GuaranLink Technology

GuaranLink's 4-tier connection check helps cellular devices automatically detect connection issues, such as an unresponsive base station or deterioration of the connection quality below an acceptable level, and triggers the recovery process to resume cellular connections before these issues lead to a complete network failure. GuaranLink checks the following four key aspects of a cellular connection:

  • ISP Connection Check
  • Cellular Connection-Alive Check
  • Packet-Level Check
  • Transmission Connection Check

The ISP initial connection check is the first step in GuaranLink's connection process, and is run whenever a cellular device registers with the base station. If the cellular device fails to register with the base station within the timeout period, the GuaranLink recovery process will be activated.


Cellular connection-alive checks are vital for cellular devices that continuously transmit data to the control center. The cellular connection check also includes a transmission connection check to provide higher connection reliability. In addition to detecting the data-transmission rate, the OnCell cellular devices keep the cellular connection alive by performing DNS lookups or sending ping commands to obtain the IP address of the intended receiver, remote host, and control center. Although the transmission connection check can increase airtime costs, it is necessary in some critical cellular applications to ensure continuous connectivity.


Cellular devices need a reliable connection to the base station as well as the control center. The packet-level connection check ensures that there is a reliable link between a cellular device and the base station by periodically sending DNS lookups and remote-host pings, even when no data transmission is in progress, to check if a cellular network is available.


The OnCell cellular devices should receive data polling requests at regular intervals from remote hosts and the control center to keep the connection active. If no polling request is received within the time-out period, the GuaranLink recovery process is activated to ensure that the cellular connection is kept alive.