Push Email - An Introduction

Push Email is a phrase of which you will almost certainly be aware, as it is used with increasing regularity when talking about smartphones and email systems. Initially a tool for large corporations, push email is growing in its availability to end users who do not wish to run their own mail servers. This article aims to explain the basics of push email, looking at the differences between “push” and traditional “pull” email as well as individual email solutions. There is no guarantee that all of these solutions will be available on all handsets, but we hope that it will help you make an informed decision when looking to purchase a new smartphone.

What is “push” email?

When most people think of “push” email, they think of having email arrive (whether on their smartphone or their PC) as soon as it arrives at their mail server. Either that, or they think of RIM’s BlackBerry devices, 

In practice, email is not received on the smartphone the instant at which it is received on the mailserver- generally, there is a few seconds’ delay, but, this tends to be accepted.

An example of a “push” implementation:
• Alan is out of the office, but wants to keep up with his email as and when they arrive- he sets up “push” email on his smartphone, and heads off to his meeting.
• Ben sends an email to Alan’s email address.
• The email travels across the Internet (remember- email is inherently insecure), until it finds Alan’s mail server.
• When it reaches Alan’s mail server, it is immediately pushed to Alan’s smartphone, for Alan to read.

A quick technical overview of “push” email

Different push email solutions work in different ways.

For example, with Microsoft’s Direct Push system, the smartphone sends an HTTP request to the Exchange server, asking to be notified when something (email, calendar appointment etc) changes on the server. This request lasts for the shorter of (a) a timeout period and (b) a change on the server. If there is a change, the Exchange server responds to the smartphone with details of the folders in which the changes have occurred. Upon receiving this response, the smartphone sends a synchronization request in respect of each of the folders notified by the server, and the server delivers the details of the changes – depending on signal strength / connection speed, this takes between 5 and 10 seconds.

If there is no change within the timeout period, the Exchange server sends an empty response to the smartphone. In either case, when the smartphone receives the Exchange response, it reissues the HTTP request – essentially, this is a looping process, and the issue / receive loop is often referred to as the “heartbeat”. Each heartbeat is 309 bytes, and, by default, a heartbeat is issued every 15 minutes. Thus, in addition to the size of any of the actual changes, the figure usually linked to the heartbeat is approximately 1MB / month (309B * 4 (number of 15 minute periods in an hour) * 24 (number of hours in the day) * 31 (maximum number of days in a month) = 919584B = approximately 898KB); if you are not on an unlimited data plan, you should factor this extra megabyte into your decision.

The IMAP IDLE system works in a similar manner. A “traditional” IMAP system works by notifying the smartphone of any changes in the folders on the server when the user is actively monitoring the server; however, this only works when the mail client on the smartphone is active, and thus notifications stop when a user stops using the mail application or puts the smartphone away. IMAP IDLE issues a “NOOP” (“No Operation”) command to the IMAP server at a regular interval, usually every 15 minutes. By sending this command, the connection is kept active, and thus the user is notified of any changes. This is different to Direct Push system above, in that there is no issue / receipt loop, but the overall effect and implementation of the IMAP IDLE “NOOP” issue is similar.

In any case, it is worth noting that a “push” system only operates once the email (or other change) arrives at the recipient’s server- this is different to the time at which the email is sent. As email could be routed through many servers across the Internet, looking for its correct destination, email can be delayed or even lost, thus arriving late / never arriving at the recipient’s mail server. This across-the-Internet routing, coupled with the plain-text nature of email, forms the basis of the reasoning as to why email is an inherently insecure system.

What are the differences between “push” email and “pull” email?

The main difference between “push” and “pull” is that a “push” system does not require a request from the smartphone each time the users wishes to check for email, but instead relies on an open but intermittently renewed HTTP request, whereas a traditional “pull” system requires the user to send a full send/receive command each time the user wants to poll his/her mailbox.

In practice, it is possible to schedule a “pull” system, so that it polls for email on a regular basis- this may be perfectly adequate for your needs. However, the send/receive operation requires more data to be transmitted than the “push” system’s heartbeat, and thus may be less suitable (more expensive) for constant use.

Nearly all smartphones allow you to use “pull” email without installing any extra software on your machine, and should work with most commonly-available email providers (Hotmail being a notable exception to this, and some people report problems with Yahoo! mail).

How do I get “push” email?

So you’re convinced that you would benefit from a “push” email system – but how to do you actually get one? To some extent, this depends on your situation, and which device you have.

If you intend to access your work email, your first port of call will be to your IT function to see if they can help you with the relevant software, settings and security access. Many corporations offer “push” email solutions, although some will mandate particular devices, or even require that they are company-supplied devices, to ensure security and compatibility. If you want to access your work system and are not responsible for the system yourself, make sure you check what you need before parting with any money!

For personal emails on your mobile device you will need a complete solution and the options vary in terms of price and complexity so you need to make sure you choose the right one for you. Bear in mind that, in addition to your hosting costs, you will need to take into account your data charges with your mobile service providers. Some “push” email services are offered through mobile service providers, and they may nil-rate your data charges for data transferred via your “push” solution, but, as with all subscriptions, you should check what usage limits apply, and the cost if you exceed this limit. If your “push” system is independent of your mobile service provider, and you are on a flat rate tariff, data charges may not be a problem, but, if you pay for your data on a per kilobyte basis, your bill could rack up quite quickly, especially if you use the service heavily.

Microsoft Exchange’s “Direct Push” (also known as “Exchange ActiveSync”):
Perhaps surprisingly, this system is available for more than just Windows Mobile devices, although you may need extra software.
• Windows Mobile 2003 SE and earlier: you will need extra software to take advantage of “Direct Push” – for example, Dataviz’s “RoadSync” (http://www.dataviz.com/products/roadsync/winmobile/index.html?redirect=rs_wm2003.
• Windows Mobile 5: provided that your smartphone has AKU2 or higher, it will be capable of using “Direct Push” without any extra software- it is included as part of ActiveSync. Most smartphones now come with the necessary AKU version.
• PalmOS: Palm Inc. has made available a free software patch to enable “Direct Push” on its range of PalmOS Treos. Further information is available at http://euro.palm.com/uk/en/products/easupdate/index.html. Alternatively, DataViz’s “RoadSync” product is available for PalmOS (http://www.dataviz.com/products/roadsync/palmos/index.html).
• Symbian: DataViz’s “RoadSync” product is available for a number of Symbian platforms.

You will also need an account of an Exchange 2003 server (which must have Service Pack 2 installed). You can either run your own Exchange server (not really practical for individual users, due to the costs involved, as well as the need to understand what you are doing), or else use  commercial Exchange 2003 host. If you search the web, there are several companies offering basic Exchange accounts for free, hoping that you will be persuaded to upgrade to their “premium” subscription services. You may like to make use of these facilities, but, do bear in mind that your email, and potentially your calendar, contacts and tasks information will be stored on their servers; there may not be a problem with this, but, it is something to bear in mind.

There are commercial solutions available that do everything for you and the Exchange Email service from Fasthosts is a good example- although, the issue of storing your data on a third party server still applies. For £9.99 per month you get a 1GB Exchange 2003 mailbox which allows direct push email, a copy of Good Mobile Messaging which is compatible with Windows Mobile, Symbian and Palm devices, a copy of Outlook 2003 and access to your contacts and calendar is also included. There is a free 30 day trial which you may want to take advantage of to ensure your device works well with the solution provided. Of course, you should shop around to find the best deal to suit your situation.

1&1 also offer a paid for Outlook exchange solution that costs from £7.04 per month and once again comes with a copy of Outlook 2003. When you consider the costs of Outlook 2003 on it's own this is a good deal, especially if this is a software product you are going to purchase anyway. Remember that you can also sync your contacts, calendar and tasks with this solution where you are so you are not jsut getting push email.

IMAP IDLE:
• Windows Mobile: an independent review of email applications has concluded that the best application for IMAP IDLE support is FlexMail 2007 from Web Information Solutions. If you already have an IMAP IDLE-enabled account, FlexMail could be a much cheaper solution than paying for another hosting package or other “push” email service.
• PalmOS: Chattermail from Marc Blank enables IMAP IDLE functionality on a Treo device. There is a trial version available, so you can make sure that you are happy with it before parting with cash. They also offer an IMAP email account. You should be aware that ChatterMail is no longer actively developed because Marc now works for Palm but, it appears to be a pretty stable piece of software as it currently stands.
• Symbian: In addition to on-device software, you will need an IMAP IDLE-enabled email account. If you already have an IMAP email account, you should check with your service provider as to whether IMAP IDLE is available- some providers do not support IDLE.

BlackBerry Connect:
If you have access to BlackBerry infrastructure, you might be able to take advantage of it on your smartphone via BlackBerry Connect. The BlackBerry Connect client is not available for all devices, and so you should check with whoever is responsible for your BlackBerry infrastructure. Some mobile service providers offer subscriptions to BlackBerry Connect.

Emoze:
Emoze (http://www.emoze.com/) is a “push” email solution for Windows Mobile and Symbian devices, and can be download and used free of charge. Components are installed on your PC and smartphone, and your emails are pushed to your smartphone as soon as they are received in Outlook on your PC. As such, you will need to configure an appropriate Send / Receive schedule in Outlook This system requires that your PC is left on with Outlook and Emoze running at all times when you wish to receive your email..

Visto:
Like BlackBerry Connect, if you have access to Visto infrastructure, you might be able to take advantage of it on your smartphone via the Visto client. The Visto client is not available for all devices, and so you should check with whoever is responsible for your Visto infrastructure. Some mobile service proviers offer subscriptions to Visto – for example, Vodafone offers this service under “Vodafone Business Email”.

Goodlink:
Like BlackBerry Connect, if you have access to Goodlink infrastructure, you might be able to take advantage of it on your smartphone via the Goodlink client. The Goodlink client is not available for all devices, and so you should check with whoever is responsible for your Goodlink infrastructure. Some mobile service proviers offer subscriptions to Goodlink.

Third Party Applications
Besides FlexMail and Chattermail there are some other solutions on the market so a well thought internet search can bring up many other alternatives. We have mentioned the main ones that have been proven to produce good results and can recommend those as the first stop in your 'push; search.