Opengear models with an internal cellular modem can be configured in three primary modes of operation:
- Out-of-band (OOB) access
- Always-up OOB
- Failover OOB
- Dormant failover OOB
These modes of operation are summarized below.
Whichever mode you choose for your Opengear device, it is imperative that you take time to familiarize yourself with and implement the recommended measures to secure your cellular connection and mitigate data overage charges.
Also note that if regularly idle, long-lived cellular connections (particularly "always-on" connection modes) will generally need the cellular modem watchdog enabled to ensure availability.
In this mode, the Opengear device is primarily an access server for remote, inbound connections to serial/USB console ports and managed devices – i.e. a "cellular console server".
Always-up/failover/dormant failover schemes determines how and when the Opengear device activates its cellular connection. These schemes are covered in detail in this article.
In OOB access mode, an important consideration is how to access the Opengear device's cellular IP address, e.g. enabling inbound access to an Opengear device behind carrier NAT.
You may also configure your cellular Opengear device as a standalone cellular gateway router as detailed in this article, capable of providing Internet connectivity to a LAN. This mode may be used in conjunction with providing OOB access.
IP Passthrough (F2C)
The IP Passthrough feature allows the Opengear device to offload its cellular IP to a dedicated router, such as a Cisco ISR, as detailed in this article, while maintaining inbound connectivity for OOB access via Service Intercepts.
From the Opengear device's perspective, IP Passthrough is an "always on" mode of operation with the dynamic failover component being controlled by the downstream router.