So how do I choose between two carriers or two SIMs on the same network?

Typically two different carriers provide the strongest redundancy because you avoid a single network outage affecting both SIMs. If both SIMs sit on the same network, you still gain some resilience for plan management and failover behavior, but the geography and core network diversity is limited. If you can’t get two carriers, we can design a resilient setup using the same-network SIMs by configuring health checks, failover timing, and preferred SIMs, and by testing under realistic outages at the site. This includes defining health-check targets, failure thresholds, retry timing, and the conditions for returning to the primary service. Comset can review site conditions and propose the best approach, and help plan a site-specific failover test.