Preparing for Mobility in an Exchange 2003 Environment

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The ability to synchronize Pocet PC devices and access Exchange information from a mobile phone no longer needs to be a planned and budgeted decision. It can be just the decision to enable mobile access for mobile devices. Exchange 2003, both the Standard Edition and Enterprise Edition of the server software, fully support the connectivity and synchronization of Pocet PC “enabled devices and access by mobile phone devices. As with any technology that comes free and built in, the key is not how to install the software, but rather how to configure it properly and optimize the configuration to meet the needs of the organization.

Understanding ActiveSync Versus Outlook Mobile Access

Exchange 2003 mobility includes two separate components , Exchange ActiveSync and Outlook Mobile Access. Exchange ActiveSync is used to synchronize Pocet PC “enabled devices with Exchange data such as email messages, calendar appointments, and contacts. Normally when users with a Pocet PC device want to synchronize their information, they have to place their device in a cradle connected to their desktop computer. Not only does the cradle minimize the user's ability to truly be mobile, it usually means that the calendar and information on the device is not in sync with the information being managed and accessed by others in the organization. Many users of Palm PDAs and early Pocet PC devices complained that they received dozens of appointment conflicts and missed critical information because their mobile device was not updated to the server at the office. For many mobile users, the ability to have an up-to-date calendar or to receive email messages wirelessly required the purchase and use of yet another mobile device, such as a Research in Motion (RIM) Blackberry. However, with full mobile synchronization capabilities of using Exchange 2003 ActiveSync, a mobile Pocet PC user can have real-time synchronization to Exchange data.

The Outlook Mobile Access component built in to Exchange 2003 provides the capability of a mobile phone to access Exchange information using real-time access. With a wireless phone that supports the Wireless Application Protocol (WAP) 2.x or a device that supports XHTML browser access, a mobile phone user can request access to an Exchange 2003 server to view email messages, calendar appointments, and contacts. With Outlook Mobile Access supporting full HTML browsers and i-Mode devices built in to mobile phones and personal digital assistants (PDA), users have flexibility in choosing the type of device they use to access their Exchange information.

NOTE

Users in Japan using Compact HTML (CHTML) can also access Exchange 2003 Outlook Mobile Access to view emails, calendar appointments, and contacts.


Functionality in Exchange 2003

The mobile functionality for support for Pocet PC synchronization and mobile phone access used to require an organization to purchase the Microsoft Mobile Information Server (MMIS) product as an add-in to Exchange 2000. However, all of the mobile functionality of MMIS is now built directly into Exchange 2003, and the functions have been enhanced.

Simply by installing Exchange 2003, Pocet PC users can immediately configure their Pocet PC device to specify the Exchange 2003 Server as the host server, and the Pocet PC will begin synchronizing mail, calendar, and contacts.

Designing and Planning a Mobile Access Exchange Environment

The designing and planning process for mobility in Exchange Server 2003 is dependent on the number of servers, location of servers, and security desired in the configuration. In its simplest configuration, a single Exchange 2003 server can act as the mailboxes server, also known as the back-end server functions , and as the interface to client systems, known as the front-end server functions .

For a small organization with fewer than 50 users all located in a single site, the organization can easily have a single Exchange 2003 server act as the front-end and back-end server. The server can host the mailboxes and be the connection point where users log on and access their mail.

When an organization has multiple locations that span across a wide distance, which could cause degrading, the organization may choose to have one or more Exchange servers in each location. This enables users in one site to access the server closest to their site, and users in another site to access the server closest to them. The two servers can be connected to flow mail between the two locations; however, the users effectively connect to the server closest to them. In this particular case, the organization could have one server in one site acting as the front-end and back-end server, and another server in another site acting as the front-end and back-end server for that site.

An organization may choose to split the front-end services from the back-end services, thus having two separate servers for a single site. The decision to have a dedicated front-end server from a back-end server is a choice of security and scalability. From a security perspective, the organization would expose the front-end server to the Internet for remote mobile access. The organization would secure and protect the back-end server because it has the mailboxes that hold data that might be confidential or require access restrictions. This splitting of the front-end and back-end servers creates a barrier between the two servers that can enable better management of information.

The other reason for having a separate front-end server is to enable scalability for front-end connectivity. If an organization has hundreds of users with very small mailboxes, the organization might need only a single back-end mailbox server, but might choose to have two to three front-end servers to host the client-to-server connectivity. An organization can load-balance the front-end servers so that the messaging administrators can manage the incoming access to the server in a way that optimizes the connection between users and servers.

In the end, an organization can have one server acting as both the front-end and back-end server, or the organization might choose to have multiple front-end/back-end combination servers for users, which might span several sites in the organization. An organization that wants to optimize the performance of front-end communications might choose to split the front-end from the back-end server, and then have several front-end servers available to load-balance incoming user connectivity.

Optimizing the Number of Front-end Servers

The correct number of front-end and back-end servers varies based on the size , number of locations, and access demands of each organization. If the decision on the number of locations and placement of servers based on the number of sites has already been made, the decision about how to scale front-end servers for mobility becomes the resulting decision. Exchange 2003 mobility connections to Pocet PC and mobile Web devices is a function of concurrent access. Even though an organization has 500 users ”all with mobile devices ”the likelihood that all 500 devices are simultaneously accessing the server is minimal. Even if all 500 devices happen to be connected at the same time, the amount of data transacted by the front-end server is limited.

By using the counters in the MMC performance monitoring tool, an administrator can calculate the load being placed on a server. For monitoring Outlook Mobile Access statistics, Exchange 2003 has the following counters:

  • Average Response Time

  • Browse Count

  • Browse Rate

  • Calendar Request Rate

  • Contact Request Rate

  • Cumulative Time for All Requests

  • Cumulative Simultaneous Browses

  • HTTP status 100 count

  • HTTP status 200 count

  • HTTP status 300 count

  • HTTP status 400 count

  • HTTP status 500 count

  • Inbox Request Rate

  • Last Response Time

  • Maximum Simultaneous Browses

  • Task Request Rate

  • Total Calendar Requests

  • Total Contact Requests

  • Total Inbox Requests

  • Total Number of Task Requests

Of these counters, the ones to monitor include Average Response Time, Cumulative Simultaneous Browses, Maximum Simultaneous Browses, and Late Response Time.

The Average Response Time and Last Response Time indicates how quickly a request is being served by the Exchange 2003 server, and whether any of the requests are being delayed ”typically due to congestion on the server. The Cumulative Simultaneous Browses and Maximum Simultaneous Browses provide comparative information about the number of users accessing the system, both on an ongoing basis and at any given time. With the four counters enabled, the performance tool looks similar to Figure 23.1. By understanding the traffic demands, late requests, and the number of users accessing the system simultaneously, an administrator can provide a basic level of assessment about whether the current server is adequate for the organization or whether an additional server is needed.

Figure 23.1. Equivalent site costs on multiple site links.

graphics/23fig01.gif

Trying Mobility Before Making a True Investment

One of the challenges organizations face in trying to test and evaluate new technologies is the cost of purchasing the devices needed to test the configuration. There are relatively easy ways for an organization to set up and test Pocet PC functionality and mobile phone functionality without having to purchase physical mobile devices.

Microsoft has available a Pocet PC emulator. The emulator provides a fully working Pocet PC 2003 device that can be configured for mobile connections to an Exchange 2003 server. The Pocet PC emulator can be downloaded from Microsoft at http://www.microsoft.com, using the keyword pocketpc emulator .

For mobile phone testing, the same requirement applies; most organizations need to have a mobile phone purchased to test the functionality of the technology. Unlike the purchase of many devices, mobile phone services typically require the contracting of at least one year of services. Even if an organization tests the mobility function and does not like how it works, it is obligated to pay for a full year of service or pay an early cancellation penalty. The best way around this is to download mobile phone emulator software, such as the one from OpenWave (http://www.openwave.com). OpenWave provides an emulation tool that enables users to establish a connection to Windows 2003.

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Microsoft Exchange Server 2003 Unleashed
Microsoft Exchange Server 2003 Unleashed (2nd Edition)
ISBN: 0672328070
EAN: 2147483647
Year: 2003
Pages: 393
Authors: Rand Morimoto

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