NetGroup problems connecting devices with different internet connection

Question

Create a chat using technology Cirrus (p2p) and class NetGroup.
If the device is a mobile phone, and has network via 3G or 4G, then connect to the same group with other devices is not happening.
For example, there are a PC and the mobile device:
1 If both are connected to one Wi-Fi:
onNetConnectionNetStatus: NetConnection.Connect.Success
onNetConnectionNetStatus: NetGroup.Connect.Success
onNetGroupNetStatus: NetGroup.Neighbor.Connect
A connection is made.
2 If both are connected to different Wi-Fi:
onNetConnectionNetStatus: NetConnection.Connect.Success
onNetConnectionNetStatus: NetGroup.Connect.Success
onNetGroupNetStatus: NetGroup.Neighbor.Connect
A connection is made.
3.If one device is connected to Wi-Fi, and the other to a 3G or G4
onNetConnectionNetStatus: NetConnection.Connect.Success
onNetConnectionNetStatus: NetGroup.Connect.Success
No connection.
Sample code that was tested:
package {
import flash.display.Sprite;
import flash.events.NetStatusEvent;
import flash.net.GroupSpecifier;
import flash.net.NetConnection;
import flash.net.NetGroup;
import flash.text.TextField;
public class NetGroupSample extends Sprite {
   private static const CIRRUS_URL:String = "rtmfp://p2p.rtmfp.net";
   private static const CIRRUS_DEVELOPER_KEY:String = "************************";
   private var _netConnection:NetConnection;
   private var _netGroup:NetGroup;
   private var _outputTextField:TextField;
   public function NetGroupSample() {
  _outputTextField = new TextField();
  _outputTextField.width = this.stage.stageWidth;
  _outputTextField.height = this.stage.stageHeight;
   this.addChild(_outputTextField);
  _netConnection = new NetConnection();
  _netConnection.addEventListener(NetStatusEvent.NET_STATUS, this.onNetConnectionNetStatus);
  _netConnection.connect(CIRRUS_URL, CIRRUS_DEVELOPER_KEY);
   private function onNetConnectionNetStatus(event:NetStatusEvent):void {
   this.traceToOutput("onNetConnectionNetStatus:", event.info.code);
   switch (event.info.code) {
   case "NetConnection.Connect.Success":
   var gspec:GroupSpecifier = new GroupSpecifier("Group1");
  gspec.multicastEnabled = true;
  gspec.postingEnabled = true;
  gspec.serverChannelEnabled = true;
  gspec.objectReplicationEnabled = true;
  gspec.routingEnabled = true;
  _netGroup = new NetGroup(_netConnection, gspec.groupspecWithAuthorizations());
  _netGroup.addEventListener(NetStatusEvent.NET_STATUS, this.onNetGroupNetStatus);
  break;
   private function onNetGroupNetStatus(event:NetStatusEvent):void {
   this.traceToOutput("onNetGroupNetStatus:", event.info.code);
   private function traceToOutput(...strings):void {
  _outputTextField.appendText(strings.join(" ") + "\n");
Tested on Adobe AIR SDK 3.2, 3.4, 13.0.0.111

Answer 1

the results you're showing indicate a symmetric NAT (that is, a NAT that uses a different translation for each unique destination).  there is no way for a peer behind a symmetric NAT to coordinate and find another peer that's behind a different symmetric NAT or behind a port-restricted cone NAT.
this posting by Matthew Kaufman explains the situation with NATs in more detail:
  https://forums.adobe.com/message/1064983#1064983
as far as "fixing" it: the issue isn't the protocol -- a symmetric NAT is inherently defective.  the only fix is to not use a symmetric NAT in your network.  unfortunately this is often outside your control (such as with your mobile provider).