What is AUTD?

What is AUTD? Always UpTo Date. This is the feature of Exchange server to keep its mobile client uptodate of emails, contacts, etc. There are two version of AUTD. AUTDv1 and AUTDv2. Let me explain.

Think of this scenario. You want all of your emails synchronized to your mobile phone inbox, as soon as the mails arrive to the exchange server. How to achive this? The mobile phone client can poll the server on frequent intervals and get the latest mails. But how frequently? if you set the interval less, the processor has to be active for more time and you may exhaust your mobile battery very soon. if you keep the interval more, there will be more delay in getting the mails. Even if you keep the frequency between less and more, one process has to run always. Running an application always is not all that good for your mobile battery life. So this approch will not suit the requirement. 

           How about the server contacting the mobile phone? But how to make the server contact the client? How the server knows the client address.? The possible solution could be,  as soon as the changes occured in user mailbox at the exchange server end, the server can send special SMS to the client. By intercepting and reading the SMS, the device can contact the server for new emails. In this way even if the mobile client is in hybernation state, it can wake-up when it receives the SMS and can sync-up with the server. This approache is AUTDv1.  But how much can we trust SMS?  How soon the SMS would be delivered to your mobile phone? How reliable the SMS will reach your mobile phone? So the reliability of this solution depends on the reliability of the service provider delivering SMS to the client. And this approach may incur other expences with the service provider for sending  SMS-es.

        Here comes the Directpush for the rescue. This is AUTDv2.  Is it really a push? How it works? Does this approach includes any other dependancy like AUTDv1? I'll  answer all these questions tomorrow.