AUTD on Unreliable GPRS Networks becomes Almost-Up-To-Date


Exchange Server 2003 provides a feature for users of Windows Mobile 2003 devices to receive their email on their device soon after it arrives in their mailbox.  We call this feature Always-Up-To-Date (AUTD) notifications and it can be enabled using the Mobile Services property page under Global Settings in Exchange System Manager. For users with mobile devices that are a bit older than those running on Windows Mobile 5 and the Microsoft Security and Features Pack, it's a step forward from scheduled sync.  Unfortunately, the feature relies on some technologies that can sometimes hinder its performance, and, in some cases, prevent it from working altogether.  I'll be discussing these setbacks below.  Exchange Direct Push, available in Service Pack 2 solves these problems. See Sami Khoury's blog post, Solving the Phone Synchronization Problem End-to-End, for a technical discussion of this new solution.


 


In the released version of Exchange Server 2003, AUTD makes use of SMTP-to-SMS technology that is provided by mobile operators in order to alert a Windows Mobile 2003 or later device that an item has arrived in the user's mailbox.  The SMS alert tickles the ActiveSync software on the device so that it connects back to Exchange Server and syncs down any new items that have arrived since the last sync session.  For many Exchange users, this feature works great but some issues have surfaced as enumerated below:


 


-      Not all mobile operators offer the SMTP-to-SMS service to their customers.  This is basically the ability to send messages to your device using an email address. We recognized this service barrier during the development of AUTD and were working on a parallel solution whereby Exchange enterprise customers would be able to send the SMTP messages to Microsoft's data center.  Microsoft would then convert these to SMS and send them to a mobile operator's SMS gateway.  Since most, if not all, modern day cell phones support SMS (aka Text Messaging), we thought we had this solved. However, the solution obviously would require connectivity agreements between Microsoft and mobile operators around the world.  Alas, we found that mobile operators were not interested enough in the feature to sign up. For Exchange customers of these mobile operators, AUTD is then not an option and schedule synchronization will have to do.


 


-      Connectivity can be hit-or-miss on wireless networks such as GPRS. Anyone who has a cell phone can attest to dropped calls every now and then. This can result in sync sessions that are disconnected or never initiated when out-of-range and also AUTD notifications being queued or altogether dropped when sent from the enterprise Exchange server.  Coupling this with the fact that users may be paying for their SMS text messaging on a per-message or per-byte basis, we needed to be careful about how often and when the Exchange server should initiate sync with an AUTD notification. The Windows Mobile guys were also thinking about this and built in a batching mechanism for dealing with incoming SMS from the Exchange server.  SMS messages are queued at the mobile operator's datacenter, and then sent when a user's device comes in to range.  ActiveSync on the device needs to swallow these queued messages and initiate just one sync back to the server.  So the device waits for three minutes once an AUTD notification is received before initiating server sync.  This can be fined tuned by changing the DWORD registry value (using a 3rd party registry editor) on the device:



 


HKCU\Software\Microsoft\AirSync\Settings\NotifySyncDelay


 


Since the release of Exchange Server 2003 three years ago, we've seen how these technological shortcomings have impacted some of our customers. With the release of Service Pack 2, you will see a radical change for the better in how we ensure that your mobile email remains up-to-date.  The SMTP/SMS technology is totally replaced with an "always connected" implementation.  I really shouldn't say "replaced" because the original feature will still be available for users of older devices.  However, any users of latter-day devices that support the new "always connected" technology should take advantage of the refinements that have been made.  I should mention that both of these features are available for implementation to all licensees of Exchange Active Sync so look for these features coming soon to your favorite device.


 


- Greg Bolles

Comments (7)
  1. Alasdair says:

    isn’t this kind of old news?

    however:

    In the UK the SMTP to SMS has never been supported all the operators manipulated the generated SMS such that it meant nothing to the device.

    To make the new AUTD  work the server must have the messaging and security feature pack (MSFP) installed.

    you will also need a windowsmobile 5.0 device that has the AKU2.0 update applied as a minimum.

  2. faespiritu says:

    Hello everyone! I am Exchange Newbie. I badly needed your help no this. i would really appreciate any help from you guys. thanks a lot.

    I’ve got single Exchange 2003 server ent. ed. OWA and OMA is working fine without activating SSL. however, when i used SSL, OMA won’t work and got an error saying “A System error has occurred while processing your request. Please try again. If the problem persists, contact your administrator.” I also found error in the Event Viewer saying:

    Source: MSExchangeOMA
    Category: (1000)
    EventID: 1503

    An unknown error occurred while processing the current request:
    Message: The remote server returned an error: (440) Login Timeout.
    Source: Microsoft.Exchange.OMA.ExchangeDataProvider
    Stack trace:
      at Microsoft.Exchange.OMA.ExchangeDataProvider.OmaWebRequest.GetRequestStream()
      at Microsoft.Exchange.OMA.ExchangeDataProvider.ExchangeServices.GetSpecialFolders()
      at Microsoft.Exchange.OMA.ExchangeDataProvider.ExchangeServices..ctor(UserInfo user)

    Message: Exception has been thrown by the target of an invocation.
    Source: mscorlib
    Stack trace:
      at System.Reflection.RuntimeConstructorInfo.InternalInvoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean isBinderDefault)
      at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
      at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
      at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
      at Microsoft.Exchange.OMA.UserInterface.Global.Session_Start(Object sender, EventArgs e)

    Message: Exception of type Microsoft.Exchange.OMA.DataProviderInterface.ProviderException was thrown.
    EventMessage:
    UserMessage: A System error has occurred while processing your request. Please try again. If the problem persists, contact your administrator.
    Source: Microsoft.Exchange.OMA.UserInterface
    Stack trace:
      at Microsoft.Exchange.OMA.UserInterface.Global.Session_Start(Object sender, EventArgs e)
      at System.Web.SessionState.SessionStateModule.RaiseOnStart(EventArgs e)
      at System.Web.SessionState.SessionStateModule.CompleteAcquireState()
      at System.Web.SessionState.SessionStateModule.BeginAcquireState(Object source, EventArgs e, AsyncCallback cb, Object extraData)
      at System.Web.AsyncEventExecutionStep.System.Web.HttpApplication+IExecutionStep.Execute()
      at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

    For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

    Can anyone help me?

    thanks a lot.

    FAESPIRITU

  3. mtvedten says:

    I have a qtek 8310 with Windows Mobile 5 and AKU 2 – but i still experience the gprs dropping the connection to the Exchange server quite often. I then need to restart the phone to get connected again. So much for AUTD;-)

  4. Vytas says:

    Morten-

    Have you changed your SSL timeout on your firewall and your front end exchange server to 900 seconds?

  5. David Magda says:

    How about the possibility of using IMAP IDLE (RFC 2177)?

    Updates are instantaneous (sp?), and almost no bandwidth is used. It would simply be necessary for the mail client to pay attention to the possible time-out of the TCP connection between itself and the IMAP server. (Perhaps leaving and entering ‘IDLE mode’ every 580 seconds (which could be user-definable value)).

    If the connection is lost (e.g., going into a tunnel, subway, etc.), the mail client simply reconnects to the IMAP server as it would when it’s first launched.

  6. Bernard Megan says:

    None of the operators in Ireland provide smtp to SMS and have no idea when it will be implemented. I have a Nokia 30 on a server here that monitors my network. Can I utilise this to trigger the sms to the PDA’s? has anyone ese tried using their own SMS device to route email?

    Cheers

  7. Peter Mac says:

    I am trying to set up a shared contact database on Exchange Server 2003 so that any changes by any moblile device will replicate on the master contact copy.  We are using HP Mobile devices with Windows Mobile Pocket PC 2003 installed.  Currently there is no way that I can see to implemplement the share since the Active Sync uses the "Users" profile to access the users contacts.  I know that setting up a shared contact is done with relative ease on the server side but cannot seem to get the Active Sync side to work correctly.  Any Ideas?

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