Windows Mobile and Push Email

One of the key areas of interest for customers at the moment is the Direct Push capabilities we are introducing shortly with Exchange 2003.

I've had lots of questions from customers and wanted to disolve some of the confusion around this as well as explain the background on the technology and it's benefit to customers.


Historically access to Exchange 2003 has been through a synchronisation mechanism whereby your device would contact the server at a pre-defined interval between 5 minutes and 4hrs and it would download any updated email, calendar or contact items.  This synchronisation uses a protocol and solution called Exchange Activesync. 

We've had that capabilitiy in Exchange 2003 by default and also previously had it with Mobile Information Server and Exchange 2000.

The recent announcement will provide Direct Push capabilities directly from Exchange 2003 (only)

What is Direct Push and how does it work?

With the release of Exchange 2003 Service Pack 2 and Windows Mobile 5.0 devices equipped with the Messaging and Security Feature Pack (MSFP) customers will have a different experience of mobile messaging with Exchange 2003.  Essentially what Direct Push provides is a mechanism to ensure your device is always up to date with the latest information in your mailbox.

With Direct Push - when a change is detected in your mailbox a trigger is sent over IP to your device to tell the device to synchronise.  The device then picks up any new email, calendar, contact or tasks.  No data is sent directly to the device except for the trigger.  If no trigger is received after a period of time then a heartbeat is sent to ensure the device is still available.  This heartbeat uses a very small amount of data which over a month period will use approx 1MB. (See data compression section later).  Through this mechanism the device will always get new items as soon as they are received whether the device roams, is on GPRS, WiFi, CDMA or any IP based network.

Many people are familiar with the mobile email experience that Blackberry provides which is termed 'Push Email' with Blackberry as a new email appears in your mailbox - the first 2kb of that email is forwarded from your Exchange server to the Blackberry Network Operations Centre (NOC) and then on to your device.   

Direct Push provides the same real-time experience as Blackberry in that when a new email is sent it is received almost immediately on the device.  In fact if you set a RIM device next to an MSFP device then they bleep about the same time (if not quicker on the MSFP device) - typically email is received between 5-7 seconds on my device after leaving my mailbox.  In reality it's like I get email on my device as soon as it's sent. 

The major benefit to IT Professionals and Security teams about Direct Push is that no data is sent to a 3rd party (the NOC) and similarly the Direct Push solution doesn't have the scaleability challenges of other Push Email solutions such as Blackberry which is limited to 500 users per server (or 2,000 if you cluster them)

In Microsoft we have over 20,000 users being provided Mobile email on Pocket PC's and Smartphone's using just 2 (yes 2) servers in Redmond.  Those Servers are managed by 2 people and also provide all other remote email services for Laptops and Web Browsers.  Check out the paper written on our own deployment -

So how do I get this Direct Push working?

For customers who are on Exchange 2003 it's really simple - you just need an Exchange 2003 Front End Server with the Mobile Services enabled running Exchange 2003 Service Pack 2 (you don't need to upgrade all backend mailbox servers) and a device running Windows Mobile 5.0 with MSFP.   Those devices will be available later this year - around the same time as Service Pack 2 is scheduled to be released (Second half of 2005)

For customers who have devices which are using a previous version of Windows Mobile (eg 2003) you can either upgrade them to Windows Mobile 5.0 (if there is an upgrade available) or continue to use the existing Synchronisation solution.  You have to have Windows Mobile 5.0 for Direct Push.

The only other thing you will need to check is the timeout you have on your SSL connections from your firewall as they need to be greater than 15 minutes.

OK - so I get the Messaging bit of MSFP - what about the S - Security?

Exchange 2003 Service Pack 2 and MSFP introduce some excellent security enhancements into Windows Mobile.  Primarily these are as follows:

1) Password Policy enforcement - You can define a centralised password policy which is enforced across all devices.  You can specify a minimum password length, strength of password, timeout and how many incorrect attempts are allowed before the device is wiped.  All this is done centrally from Exchange.

2) Device Wipe - if a user enters a password a certain number of times incorrectly (defined in Exchange as above) then the device will be wiped.  You can also set a device wipe remotely too.  The Wipe is essentially a hard reset so all data is erased and you are back to the Welcome to Windows Mobile screen (align the screen, book a dental appointment etc...)

3) Certificate support - we have introduced the ability to authenticate against Exchange with Certificates instead of  a username/password.

Data compression!

With Exchange 2003 Service Pack 2 we've also introduced Data Compression into Exchange Activesync.  Typically we see compression of data anywhere from 35% to 50% depending on the content.  Data compression really brings two benefits - firstly it obviously reduces data consumption, the second benefit is that synchronisation is much quicker!

My customers typically see data usage today of 4MB per month for Smartphone and 6-7 MB with Pocket PC.  With Exchange 2003 Service Pack 2 we'll see that drop to around 2MB and 3.5MB. 

So what else does Exchange 2003 SP2 and MSFP provide?

Well apart from Task synchronisation you also get GAL lookup - that is the ability to find people in the Global Address List and call, text or email them directly.  You can even add them to your contacts directly on the device to save you searching for them again!

For more information.....

There are some great resources available now on the page. 

1) To see how the "heartbeat" of Direct Push Technology keeps your mobile device up to date, view screenshots of the GAL Lookup and of other features, and more, register on the Microsoft Events site to watch the Secure and Scalable Messaging with Windows Mobile 5.0 webcast.

2) To see MSFP in action look at -

View video at 300 kilobits per second

3) The Community Technology Preview for SP2 has been released at: 


Comments (13)
  1. Hi Jason,

    Thanks you very much for this post… It´s much more clear now, how everything works.

    PS. Now, we just need to wait for WM5 devices !!

  2. Nino.Mobile says:

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  4. Derek says:

    Get your facts straight. BlackBerry Enterprise Server 4.0 easily supports up to 2000 handheld users, depending mainly on the server hardware and the network it is on. Normally the only limitation is MAPI.

    Read the BES 4.0 Quick Start Guide for recommended hardware.

  5. Derek says:

    Get your facts straight. BlackBerry Enterprise Server 4.0 easily supports up to 2000 handheld users, depending mainly on the server hardware and the network it is on. Normally the only limitation is MAPI.

    Read the BES 4.0 Quick Start Guide for recommended hardware.

  6. MSDNArchive says:

    Derek – my facts are correct – yes you can support 2,000 users on a server but you are effectively running 4 servers on one box as MAPI has a 500 user limitation which is the underlying technology that BES uses. Without any fault tolerance, load balancing, active failover or clustering support – I don’t think putting 2,000 users on a server is a good thing.

  7. Barty says:

    thanks for this. Interesting to hear about activesync. One question though, Bberry users have on average about 3MB/month usage. Rumour was that MSFT push email was a richer experience and far heavier usage, around 20MB, so it could be quite expensive when the bills come in. Anything to add here??

  8. Someone Else says:

    Choosing a device One of my recent projects at work has been to introduce a pilot scheme for smartphone

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