How to optimize my app for for a carrier-provided satellite network?

Is it correct that isUltraConstrained will reliably indicate a satellite connection?

Yes and no. You’ll note that isUltraConstrained is not called isCarrierProvidedSatelliteNetwork. The name tells you about the expected behaviour of the network, not the exact medium used by the network.

Should I also check for linkQuality == .minimal … ?

No. That’s not really what linkQuality was designed for. Let me explain…

Some apps wants to scale their network use based on the available network bandwidth. The canonical example of this is a video streaming app, which can switch between low- and high-bandwidth streams.

The standard way to do this is to continuously monitor network performance and adjust your network use depending on how well things are going. That approach works reasonably well, but it has one significant limitation: There’s no obvious place to start.

Video streaming apps often getting around this by starting with a low-bandwidth stream and then scaling up to higher-bandwidth streams if things go well. The obvious downside to this is that the stream always starts out ‘blocky’.

The linkQuality property provides a hint to help with this. If the link quality is good, a video streaming app might start out by using a higher-bandwidth stream, allowing it to more quickly converge on the best rate for this specific network scenario.

None of this is relevant to ultra-constrained networks, where you should always assume that the available bandwidth is very low.

Are there any additional APIs or best practices for detecting and optimizing for satellite connectivity that I should be aware of?

Yes. My general advice in situations like this is to not rely on NWPathMonitor but instead apply the constraint to the connection by setting properties on NWParameters. In this case that means setting the allowUltraConstrainedPaths property and then, once you’re connection, looking at the current path to determine whether it’s ultra-constrained.

I recommend this approach because it avoids race conditions. The problem with using NWPathMonitor is that the network state can change between when you look at it and when you make your connection. In constrast, if you constrain your connection than

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

is it a fair understanding that if my app is implemented accordingly, the app will be considered as a carrier-constrained.app-optimized app?

I don’t understand the question. Considered by who?

Also, is there a way to test(simulate) a ultra-constrained network on a device or a simulator?

I’m tackling that question on your other thread.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

I don’t understand the question. Considered by who?

My assumption is that if an app is submitted to the App Store with the carrier-constrained.app-optimized entitlement set true, Apple will review the app if it is actually optimized to a constrained network and reject the app if it is not.

So I would like to know how should I implement the app so the App Store reviewers will consider the app is optimized to a carrier-constrained network and accept it.

Or, can an app still connect to a carrier-provided satellite network without carrier-constrained.app-optimized entitlement? Is carrier-constrained.appcategory the only requirement to use the satellite network? Then what is the requirement to set the appcategory and get accepted? Or even none of those is required to connect to the satellite network?

I couldn't find any description on the Apple's public developer resources.

Thanks again!

A related additional question: will URLSessionConfiguration and URLRequest provide a property like "allowsUltraConstrainedNetworkAccess" so all requests on URLSession with this configuration won't happen on satellite mode?

Currently in Xcode 26 Beta 4, there isn't such property, but I think it would be needed. There is a common need that we should fail some on-going requests once the device connects to satellite channel.

will URLSessionConfiguration and URLRequest provide a property like

I can’t talk about The Future™ but…

I think it would be needed.

… the best way to get this feedback seen by the folks who have the power to enact change is to file an enhancement request.

Please post your bug number, just for the record.

Oh, and before you file, check this post to see whether your ultimate goal is feasible.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"