How Google works internally

To build a connection between the Google talk client and Google talk The servers are encrypted Except while using the international versions of client ,Gmails chat over HTTP, a fedrated network that  does not support encryption or using a proxy as IMLogic.The purpose of doing all this process is that messages are not necessarily encrypted from end to end, although it may have been from end to end encryption in GTalk network using Zfone or OTR (Off-the-record) chat when all participants to connect through HTTPS.