Blackout affecting Garmin inReach devices

Please provide an accessible link to something which describes this. Those of us in the US don't know what this is about.

You should be able to communicate with your inReach device, activate SOS, and receive emergency/rescue services during a blackout.  Germany has laws that require critical infrastructure be protected.  But as with any technology designed by humans, nothing is ever guaranteed 100% unfortunately. See link below. 

www.bmi.bund.de/.../critical-infrastructure-protection-node.html;jsessionid=FC2686AEDB180A20FAEFA7A068497EE8.1_cid332

If this is referring to the power grid, inReach coverage is not affected as long as your device is charged. If the grid outage is long enough, you might need a power bank to recharge the device.

There ARE ground stations involved in the Iridium network. I suppose it's possible that a ground station in a blackout area might be offline. The Iridium constellation forms a mesh network. Messages are relayed from one satellite to another as needed to reach a ground station (or the vicinity of a receiver). I don't know for sure, but it seems like this SHOULD make the network resilient when a ground station is temporarily out of service.

All communication between an iR device and ANY destination (SMS, email, another iR device) is routed through the Garmin servers. Even iR to iR device traffic does not travel directly over the Iridium satellite network.

Some message destinations, such as email and SMS, require operational non-Garmin infrastructure. For example, email requires a working Internet connection. SMS delivery requires a working SMS gateway in "the general vicinity" of the recipient's cell provider. And, of course, working cell towers. This affects end to end communication independent of the Garmin infrastructure.

I BELIEVE that device activation is recorded in the Iridium infrastructure, as well as at Garmin. I do not believe that the Garmin servers must be online to check to see that a previously activated device has a subscription.

Garmin web sites (such as explore.garmin.com) are fronted by a content distribution network provider (Cloudflare, at least in the US). These ought to be solidly reliable even in the face of localized power outages. Still, the back end web site must be up.

There are a number of components to the iR service. Availability is tracked individually. You can see the list of components and current status here;

https://status.inreach.garmin.com/

I have never, ever seen an outage for SOS. Like everything else, this depends on core Garmin servers. These would have to be massively reliable. Peripheral services, such as activation/deactivation, single sign on, weather forecasts, etc. are less reliable. 

I have no real idea (and cannot find out because Cloudflare is in front) where the core Garmin servers are located. But they, as well as backbone interconnects, must be reliable. I would expect that messages (between iR devices and the Garmin servers, not necessarily end to end) and sent track points would be as reliable as SOS. As a back country user of a safety device, that's mostly what I care about.

This is really all related to standard practice for a high-availability data centers. You always have redundant power sources (local grid, plus generators if needed), at least 2 (and sometimes more) Internet backbone connections, redundant components and/or redundant server clusters, and so forth.

Unless your in CA… 

nice explanation twolpert

one has to look at the iridium communication in different levels. To be accepted as part of maritime GMDSS system for example, Iridium had to build up lot of redundancy worldwide first. There are some services they have to organize the delivery too and for maintaining such services they are paid even when no payload traffic is generated.

This is not valid for private communication networks like inreach. They deliver it if possible, but they will not build an extra communication network to handle such traffic. This has to do the customer (~Garmin) himself.