Outlook 2003 contains several new features that can optimize client performance and can improve the overall user experience when used with Exchange Server 2003. These features include:

• Cached Exchange Mode   This feature enables you to work in a messaging environment with a perceived connection between the Outlook 2003 client and the Exchange server. Typically, users do not notice any difference in messaging performance when using Exchange cached mode. For servers, processor performance was 10 percent better in comparison to Exchange 2000 Server with Service Pack 3 (SP3). For more information about server data, see Baseline Performance for Mailbox Server (Using MAPI).
  Although both Exchange 2000 Server and Exchange Server 2003 support Cached Exchange Mode, Exchange Server 2003 includes several performance improvements implemented specifically to improve the performance of Outlook 2003 clients.
  
• RPC over HTTP   This feature enables you to access your Exchange Server 2003 account from the Internet when you are working outside your organization's firewall without any special connections or hardware, such as smart cards and security tokens. For more information about configuring Exchange Server 2003 to use RPC over HTTP, see Exchange Server 2003 RPC over HTTP Deployment Scenarios (http://go.microsoft.com/fwlink/?LinkId=24823).
  

For more information about:

• How Exchange Server 2003 improves performance for Outlook 2003, see "Outlook Improvements" in What's New in Exchange Server 2003 (http://go.microsoft.com/fwlink/?LinkId=21765).
  
• These features, see the Exchange Server 2003 Client Access Guide (http://go.microsoft.com/fwlink/?LinkId=27739).
  
• Performance comparisons of different versions of Outlook, see Client Network Traffic with Exchange 2003 (http://go.microsoft.com/fwlink/?LinkId=27020).
  

Outlook Web Access in Exchange Server 2003 provides several new features and enhancements. The new version uses gzip compression to compress data, which reduces overall network traffic by as much as 50 percent. In addition, underlying components were redesigned to take up less memory, resulting in lower bandwidth requirements. For a performance comparison of different versions of Outlook Web Access, see Baseline Performance for Outlook Web Access.

Additionally, Secure Sockets Layer (SSL) is a prerequisite to enabling compression and it does not add much overhead traffic, as shown in "Scenario 2" in Baseline Performance for Outlook Web Access. The only effect of SSL activation is the additional processor resource that you require on your Exchange servers. If you start SSL with Outlook Web Access, your messaging traffic decreases and becomes more secure at the same time.

For best connection performance, users should select the Outlook Web Access front-end server physically located closest to their mailbox server, not the Outlook Web Access front-end server closest to their present location.

For more information about:

• The new features for Outlook Web Access, see What's New in Exchange Server 2003 (http://go.microsoft.com/fwlink/?LinkId=21765).
  
• How to set up Outlook Web Access with Exchange Server 2003, see the Exchange Server 2003 Client Access Guide (http://go.microsoft.com/fwlink/?LinkId=27739).
  
• Detailed performance on Outlook Web Access, see Client Network Traffic with Exchange 2003 (http://go.microsoft.com/fwlink/?LinkId=27020).
  

Exchange Server 2003 includes Outlook Mobile Access and Exchange ActiveSync® features previously included with Microsoft Mobile Information Server. Previously, you had to install Mobile Information Server in every network domain where these services were required. Because Exchange includes built-in mobile services, installation on network domains is no longer necessary.

• Outlook Mobile Access   This feature enables users to use mobile devices to access their Inbox, Contacts, Calendar, and Tasks folders. Previous support through Exchange 2000 Server and Mobile Information Server posed limits when mobile devices were used outside users' home domains. Exchange Server 2003 eliminates this domain boundary limitation.
  
• Exchange ActiveSync   This feature enables users to synchronize their mobile devices directly with the Exchange Server 2003. Users can use their mobile carrier connection to synchronize their Exchange information to their Pocket PC Phone Edition or Smartphone device and then access this information when they are offline. Like Outlook Mobile Access, Exchange Server 2003 eliminates the domain boundary limitation in Mobile Information Server.
  

For more information about Outlook Mobile Access and Exchange ActiveSync, see the Exchange Server 2003 Client Access Guide (http://go.microsoft.com/fwlink/?LinkId=27739).

Earlier versions of Exchange do not monitor the performance experience for Outlook client users. However, with Exchange Server 2003 and Outlook 2003, administrators can analyze performance for these users.

Exchange 2003 servers record both RPC latency and errors on client computers running Outlook 2003. An administrator can use this information to determine the overall client performance and to monitor the Exchange server for errors.

Outlook clients send RPC data (for example, latency data or error code) to the Exchange 2003 server on subsequent successful RPC calls.

Note:
RPC data sent from the client computers to the Exchange server are not the primary method for detecting individual real time errors.

The client-side performance counters include:

• Client: RPCs attempted
  
• Client: RPCs succeeded
  
• Client: RPCs failed
  
• Client: RPCs failed: Server unavailable
  
• Client: RPCs failed: Server too busy
  
• Client: RPCs failed: all other errors
  
• Client: RPCs attempted / sec
  
• Client: RPCs succeeded / sec
  
• Client: RPCs failed / sec
  
• Client: RPCs failed / sec: Server unavailable
  
• Client: RPCs failed / sec: Server too busy
  
• Client: RPCs failed / sec: all other errors
  
• Client: Total reported latency
  
• Client: Latency > 2 sec RPCs / sec
  
• Client: Latency > 5 sec RPCs / sec
  
• Client: Latency > 10 sec RPCs / sec
  

You can monitor these counters with System Monitor or Microsoft Operations Manager. Additionally, the Exchange Server 2003 Management Pack for Microsoft Operations Manager provides an Outlook Client RPC Performance and Failure report. The Management Pack also has rules that are triggered by client monitoring events. These rules are located in Microsoft Exchange Server 2003\Exchange Event Monitoring\Information Store service\ of the Exchange Server 2003 Management Pack:

• Client: Percentage of successful client RPCs is less than the specified threshold.
  This rule is triggered by event MSExchangeIS 9640.
  
• Client: Averaged client RPC latency is greater than the specified threshold.
  This rule is triggered by event MSExchangeIS 9641.
  
• Client: The number of client RPC errors and latency warnings issued is greater than the specified threshold.
  This rule is triggered by event MSExchangeIS 9642.
  

For more information about the RPC-related operations that you can monitor using Microsoft Operations Manager, see What's New in Exchange Server 2003 (http://go.microsoft.com/fwlink/?LinkId=21765).

For more information about Microsoft Operations Manager, see the Microsoft Operation Manager Web site (http://go.microsoft.com/fwlink/?LinkId=16198) and the Better Together: Microsoft Operations Monitor and Exchange Server 2003 Web site (http://go.microsoft.com/fwlink/?LinkId=18176).

For assistance with troubleshooting RPC-related problems, use the Microsoft Exchange Server Performance Troubleshooting Analyzer Tool (http://go.microsoft.com/fwlink/?LinkId=55884).