As your business grows, more and more of your network users are likely to want to connect remotely with a growing diversity of devices. The problem is how to make e-mail and other corporate resources accessible to those who need them while maintaining control and security.

For many of today's workers, it's no longer enough to simply wait until they get to the office to check and handle their corporate e-mail, or even to have the ability to get their mail at home. In a competitive business climate, a few hours can make a big difference, and executives, sales reps, and other employees want to be able to get their messages whether they're on the road or out on the town.

There are a variety of portable devices that make it easy for them to do so: notebook computers, handheld devices (often called PDAs, but many of them have much more computing power and capability than a true PDA) and "smart" phones of different types.

A few years ago, accessing the Internet over your cell phone wasn't a pleasant experience; network speeds were excruciatingly slow and access services were excruciatingly expensive. Today, prices have come down and performance has improved. The old GSM connection speeds of under 10 kbps are now up to 54 kbps or more. As using mobile devices to connect to the Internet has become easier, network users in many cases have come to prefer them over the traditional laptop computer, especially for simple tasks like getting e-mail. To get their corporate e-mail, they need to be able to use these devices to connect to the corporate network.

As your business grows, more and more of your network users are likely to want to connect remotely with a growing diversity of devices. The problem is how to make e-mail and other corporate resources accessible to those who need them while maintaining control and security.

Mobile client types and protocols
Mobile clients include not only the typical laptop/notebook computer, but a variety of other devices, including:

• Handheld computers running Pocket PC and Palm operating systems
• Cellular mobile phones running the Microsoft Windows Mobile Smartphone OS, Symbian OS,
• Palmsource and other mobile operating systems
• Research in Motion (RIM) devices, also known as Blackberry
• A mobile connectivity solution needs to take into account the protocols and services used by the mobile clients. These can include:
  • WAP: The Wireless Application Protocol, a standard for Internet access (Web, e-mail) from mobile phones
  • SMS: Short Message Service, used on digital GSM phone networks for sending text messages of up to 160 characters.
  • WTLS: Wireless Transport Layer Security, which handles privacy and authentication for WAP services (similar to SSL)

Mobile devices can also function either as "thin" or "fat" clients. Thin clients rely on a server to do all processing. For example, WAP browsers are can be used by thin clients to display Web sites that use the Wireless Markup Language (WML), which is an XML language, or XHTML-Mobile Profile (XHTML-MP). The former was used by WAP 1.0 and based on the Handheld Device Markup Language (HDML) created by Unwired Planet/Openwave. The latter is used with WAP 2.0 phones, although they also support WML.

The point is that a scalable mobile connectivity solution must support many different protocols and services that are not normally used by standard desktop and laptop/notebook computers.

Mobile VPN solutions
VPN client software is available for mobile devices. For example, phone vendors such as Nokia make VPN clients for their phones and other mobile devices (in Nokia's case, these are Symbian based).

Pocket PC devices include built-in VPN client functionality. VPN clients are also available for Windows Mobile devices from third parties such as Apani Networks, to work with their own VPN gateways. You can get third party VPN clients for Treosmartphones and Palm OS handheld computers from Mergic and movianVPN. There are VPN clients available, either built in or from third parties, for most popular mobile devices.

The VPN clients let users connect seamlessly to your company's VPN servers, without any requirement for changing your VPN and authentication infrastructures. They're compatible with popular VPN gateways such as those made by Cisco and CheckPoint. This lets you scale your VPN accessibility to mobile device users, and they include security measures to protect your data as it's transmitted to or from the mobile devices.

Managing mobile traffic
Products such as Big-IP, a hardware-based solution from F5 Networks, can help you to route application traffic to the appropriate server as it comes into the network, so that SMS traffic goes to SMSC gateways, traffic from handheld computers can be directed to specific servers, and so forth. It can also increase performance by offloading SSL processing, perform health checking and enforce security measures. It allows you to integrate your mobile applications with the rest of your IP applications in a centralised solution.

The need for scalability
It's particularly important, when planning a mobile connectivity solution, to plan for scalability. It's likely that only a subset of your company's employees will take advantage of mobile connectivity at first, but as capable devices become more affordable and thus more ubiquitous, more of them will want to avail themselves of the technology. You need to be ready to add the capacity for supporting more mobile users as demand grows. Before deploying a mobile connectivity solution, ensure that it can handle that growth.

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