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The mobile enterprise
Matt Nicholson looks at the opportunities and the issues that arise when you integrate mobile devices into your organisation?s infrastructure.
Author: Matt Nicholson
Last updated: Mar 2004
Mobile devices are already part of your company's infrastructure. Whenever
your staff use their mobile phone to make a business call from a train,
plug their laptop into a hotel room's modem socket to download files from
the server, or synchronise their PDA with their desktop before visiting
a client, they are extending the infrastructure of your organisation beyond
the office walls. However such activities only begin to explore the scenarios
possible with mobile technologies. Client Power The mobile infrastructure Working with Wi-Fi
For example, if that phone is capable
of displaying WAP Markup Language (WML), or that PDA can display HTML,
then it could be functioning as a client to your enterprise applications.
Technologies such as Microsoft's ASP.NET provide powerful platforms for
extending enterprise applications to a wide range of mobile devices through
WML and HTML.
WAP (Wireless Application Protocol)
phones based on GSM technology, which restricts download speeds to just
9,600 bits per second (bps), are frustratingly slow. More modern devices,
such as the Orange SPV, use GPRS technology and can transfer data at up
to 57.6Kbps. These incorporate Web browsers that can display standard
HTML, which considerably simplifies software development – particularly
if your application is already catering for conventional Web clients.
However, such applications can only
function when the mobile device is connected to the back-end server. GPRS
connections usually involve the user buying into a contract that includes
transfer of an initial block of data each month, with further charges
for every additional megabyte, and such contracts are expensive. Costs
can be kept down by simplifying the user interface – no fancy logo
images, for example – but call charges still mount up.
Users can of course connect to the
application using more traditional methods, such as dialling in over a
land line. The call could be placed directly to a modem attached to the
server itself, although this might prove expensive if the user is abroad,
and does require you to have sufficient modems if more than one person
at a time is likely to connect. Alternatively, the call could use Virtual
Private Networking (VPN) to connect to the server in a secure manner through
a local Internet Service Provider (ISP).
Yet another option is to take advantage
of the increasing number of public places that provide Wi-Fi access, including
hotels, airports and train stations. This is fairly new, and signing up
for Wi-Fi access is not cheap, but it does give you transfer rates of
up to 11Mbps.
Devices such as these do make excellent Web clients, but their real strength
lies in the computing power offered by the devices themselves. On the
Microsoft side, a modern Pocket PC or even a Microsoft Smartphone device
offers as much computing power as you would have found on a desktop only
a few years ago. Furthermore, the appearance of the .NET Compact Framework
and SQL Server CE means that you can use the same tools, and indeed much
of the same code, as you would your desktop clients.
The beauty of this scenario is that
your users do not have to maintain a connection to the server while using
the application. Instead the client application can cache data locally,
ready for synchronisation with the server when a connection can be established.
For example, your sales team could
be armed with Smartphone 2002 or Pocket PC 2002 Phone Edition devices
which are running a custom-built application for displaying customer details
and capturing orders. Before they leave the office in the morning, they
plug the device into the cradle attached to their workstation and synchronise
with the server using ActiveSync. They then disconnect the device and
leave the office to visit their prospective customers.
Once at the customer’s premises,
your sales team can enter order details directly into the mobile application
and have instant access to information about the customer’s past
sales records, outstanding orders and business patterns. If their device
has a GSM or GPRS signal at the time, then any orders or information updates,
can be fed directly back to the server there and then. Otherwise they
can wait until they reach an area that does have a signal before synchronising.
Alternatively, if they are using a Pocket PC that does not have wireless
connectivity, they can synchronise from a hotel room using a dial-up connection,
or wait until they return to the office where they can plug in to ActiveSync.
Such a scenario can bring enormous
benefits, both in customer relations and in reduced errors, particularly
where orders previously had to be re-keyed into the server application.
However such applications do have to be designed carefully to minimise
network traffic, particularly where the connection might be slow. Your
sales team, for example, will probably only need the data for their individual
clients, or just for prospective customers in the region they are visiting.
SQL Server CE comes with its own mechanisms
for data synchronisation, but your application may not need such powerful
database management facilities. As an alternative, the .NET Compact Framework
offers considerable support for XML Web Services, as does the .NET Framework
itself. A custom-built XML Web Service can offer a very effective mechanism
for linking your mobile application to the server, allowing the application
to access remote objects through standard XML messages over HTTP. Furthermore,
Visual Studio .NET does automate much of the work involved in creating,
discovering and using XML Web Services.
XML Web Services are particularly
effective where the application has been optimised to minimise the amount
of data that has to be transferred. The messages involved in an XML Web
Service exchange are very compact, which means that a well-designed application
can be very responsive even if the only connection available is at 9,600bps
through GSM.
A key component for any Windows-based organisation looking to extend its
infrastructure out to mobile devices is Microsoft Exchange 2003. This
includes Outlook Mobile Access (OMA) which gives mobile clients direct
access to Exchange Server data. With OMA installed, a Pocket PC or Smartphone
device can use Exchange Server ActiveSync to synchronise Pocket Outlook
data directly with Exchange 2003 using HTTP and XML protocols, instead
of having to connect through an Outlook client on a desktop PC.
Alternatively, OMA can generate a
version of Outlook in HTML, CHTML (supported by i-Mode) or XHTML (supported
by WAP 2.0) which allows mobile devices to connect to Exchange Server
and access emails, contact information, schedules and so forth in a suitable
format. Users can also configure OMA so that urgent e-mail messages and
other notifications (as determined by Outlook Rules) are sent to their
phone as Short Message Service (SMS) messages.
With Exchange 2003 installed, administrators
can manage their users’ mobile characteristics through Active Directory
extensions. Security is obviously a big issue when it comes to mobile
connectivity, as mobile users are by definition on the wrong side of the
company firewall. Authentication has to be handled with care, and here
Exchange 2003 allow for several different approaches.
The simplest and least secure is
to authenticate mobile users directly against the company’s internal
domain. More secure and more flexible is to create a separate trusted
domain for mobile users that shadows the company domain. Finally, you
can create a separate forest that uses LDAP simple bind to allow access
to Exchange accounts only. This is more complex, but is also the most
secure option.
The mobile computing features built
in to Exchange 2003 replace Mobile Information Server 2002 which was discontinued
at the end of January 2004.
The Windows platform probably offers
the most to enterprises looking to extend their applications out to mobile
users, although Java-based platforms and tools for working with Symbian
and Palm devices are available. Such a move requires considerable planning
and does of course raise security issues, however the benefits in terms
of increased productivity, greater consumer satisfaction and reduced cost
can be enormous.
It may be that you don’t need the wide area connectivity provided
by the national GSM and GPRS networks. Instead you may be able to gain
considerable benefits simply by extending your network out into the factory
floor, the warehouse or the stock yard. Such an environment may not suit
conventional network cabling and desktop workstations. An alternative
is to issue your staff with smaller Pocket PC devices, which can be ‘ruggedised’
to withstand more challenging environments, and install your own wireless
network.
This involves connecting one or more
strategically placed wireless Access Points to your network hubs, and
issuing one of the many plug-in wireless CompactFlash or PC Card devices
to your staff. Most current hardware conforms to the 802.11b standard,
and indeed an increasing number of laptops now come with 802.11b connectivity
built in. The 802.11b standard supports data transfer rates of up to 11Mbps
(comparable to slower Ethernet speeds).
A more recent standard is 802.11g
which boasts speeds up to 54Mbps, and backward compatibility with 802.11b.
Most 802.11b or 802.11g hardware sports the Wi-Fi logo which indicates
it should work with Wi-Fi equipment from other manufacturers. Windows
CE .NET, Windows 2000 and Windows XP all include support for Wi-Fi.
802.11b has a range of about 100 metres
from the base station, although the range is considerably reduced through
brick or metal. This does of course raise security issues, as anyone within
range of your Wi-Fi signal can piggy-back your Internet connection or
hack in to your network.
Wi-Fi does support the Wired Equivalent
Privacy (WEP) protocol, which uses a 40-bit private key, and all the major
vendors have implemented their own 128-bit version of WEP encryption.
However, many products do not have WEP encryption and authentication enabled
by default, and it is surprising how often they are left that way after
installation. Furthermore, WEP is fairly easy to hack. Microsoft has worked
with Cisco to develop a stronger security protocol called 802.1x which
has been published by the IEEE and is built into Windows XP and Windows
Server 2003.
You may not mind that guy with his
laptop sitting in the café opposite your office borrowing your
Internet bandwidth, but he might equally be playing with the company accounts.
If you do install Wi-Fi, make sure you secure it as well.
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