Q:

How to determine the iOS connection type (Edge, 3G, 4G, Wifi)?

How is it possible to determine the iOS connection type? 
I want to know if there is Edge, 3G, 4G oder Wifi available at this moment on my device.
This information I need to load different data with a different size. 
So, I don't want to load an image of 4 MB with a connection type "Edge". 

A:

For swift we can use following function:
func getNetworkType()->String {
    do{
        let reachability:Reachability = try Reachability.reachabilityForInternetConnection()
        do{
            try reachability.startNotifier()
            let status = reachability.currentReachabilityStatus
            if(status == .NotReachable){
                return ""
            }else if (status == .ReachableViaWiFi){
                return "Wifi"
            }else if (status == .ReachableViaWWAN){
                let networkInfo = CTTelephonyNetworkInfo()
                let carrierType = networkInfo.currentRadioAccessTechnology
                switch carrierType{
                case CTRadioAccessTechnologyGPRS?,CTRadioAccessTechnologyEdge?,CTRadioAccessTechnologyCDMA1x?: return "2G"
                case CTRadioAccessTechnologyWCDMA?,CTRadioAccessTechnologyHSDPA?,CTRadioAccessTechnologyHSUPA?,CTRadioAccessTechnologyCDMAEVDORev0?,CTRadioAccessTechnologyCDMAEVDORevA?,CTRadioAccessTechnologyCDMAEVDORevB?,CTRadioAccessTechnologyeHRPD?: return "3G"
                case CTRadioAccessTechnologyLTE?: return "4G"
                default: return ""
                }

            }else{
                return ""
            }
        }catch{
            return ""
        }

    }catch{
        return ""
    }

}

A:

in Objective C:
first import  @import CoreTelephony.
Reachability *reachability = [Reachability reachabilityForInternetConnection];

    [reachability startNotifier];

    NetworkStatus status = [reachability currentReachabilityStatus];

    if(status == NotReachable)
    {
        //No internet
    }
    else if (status == ReachableViaWiFi)
    {
        //WiFi
    }
    else if (status == ReachableViaWWAN)
    {
        CTTelephonyNetworkInfo *netinfo = [[CTTelephonyNetworkInfo alloc] init];
        NSString * carrierType = netinfo.currentRadioAccessTechnology;
        if ([carrierType isEqualToString:CTRadioAccessTechnologyGPRS]) {
//             @"2G";
        } else if ([carrierType isEqualToString:CTRadioAccessTechnologyEdge]) {
//             @"2G";
        } else if ([carrierType isEqualToString:CTRadioAccessTechnologyWCDMA]) {
//             @"3G";
        } else if ([carrierType isEqualToString:CTRadioAccessTechnologyHSDPA]) {
//             @"3G";
        } else if ([carrierType isEqualToString:CTRadioAccessTechnologyHSUPA]) {
//             @"3G";
        } else if ([carrierType isEqualToString:CTRadioAccessTechnologyCDMA1x]) {
//             @"2G";
        } else if ([carrierType isEqualToString:CTRadioAccessTechnologyCDMAEVDORev0]) {
//             @"3G";
        } else if ([carrierType isEqualToString:CTRadioAccessTechnologyCDMAEVDORevA]) {
//             @"3G";
        } else if ([carrierType isEqualToString:CTRadioAccessTechnologyCDMAEVDORevB]) {
//             @"3G";
        } else if ([carrierType isEqualToString:CTRadioAccessTechnologyeHRPD]) {
//             @"3G";
        } else if ([carrierType isEqualToString:CTRadioAccessTechnologyLTE]) {
//             @"4G";
        }

    }

A:

CoreTelephony.framework is needed.  
let networkInfo = CTTelephonyNetworkInfo()
let networkString = networkInfo.currentRadioAccessTechnology

if networkString == CTRadioAccessTechnologyLTE{
  // LTE (4G)
}else if networkString == CTRadioAccessTechnologyWCDMA{
  // 3G 
}else if networkString == CTRadioAccessTechnologyEdge{
  // EDGE (2G)
}

