---
title: "activatePreferredSliceForCategory(_:)"
framework: coretelephony
role: symbol
role_heading: Instance Method
path: "coretelephony/ctslicingmanager/activatepreferredsliceforcategory(_:)"
---

# activatePreferredSliceForCategory(_:)

Activates a preferred network slice for new connections.

## Declaration

```swift
final func activatePreferredSliceForCategory(_ appCategory: CTSlicingManager.AppCategory) async throws
```

## Parameters

- `appCategory`: The doc://com.apple.coretelephony/documentation/CoreTelephony/CTSlicingManager/AppCategory to activate. Available categories include: communication: An app category for communication apps like messaging and voice calls. gaming: An app category for gaming apps that require low latency and high performance. streaming: An app category for streaming apps that require high bandwidth and consistent throughput.

## Discussion

Discussion Call this method before establishing network connections to route your app’s traffic through a specific network slice. After calling this method, new network connections that your app establishes use the specified slice category. The array that availableSliceAppCategories returns must include the specified category for activation to succeed. important: This method only affects connections that the system creates after calling it. Existing active connections continue to use their current routing until the system closes them. do {     // Activate the gaming slice before starting a multiplayer session.     try await CTSlicingManager.shared.activatePreferredSliceForCategory(.gaming)

// Establish network connections for gaming traffic.     // New connections route through the gaming network slice.     // Existing connections remain on their current routing. } catch POSIXError.ENOTSUP {     print("Network slicing isn't currently available.") } catch {     print("Failed to activate slice: \(error)") } note: POSIXError.ENOTSUP if network slicing is not currently available. POSIXError.EINVAL if an invalid parameter or system error occurs.

## See Also

### Managing network slicing

- [disableSlicing()](coretelephony/ctslicingmanager/disableslicing().md)