Jan 31

Exchange 2010 and support for UDP

Microsoft has announced that support for User Datagram Protocol (UDP) functionality will be added back into Microsoft Exchange Server 2010.

Because UDP notification support was removed from Exchange 2010, users of Outlook 2003 experienced latency in sending and receiving e-mails when connected to Exchange 2010.  More details about this issue can be found in the related Microsoft Support article: http://support.microsoft.com/kb/2009942. While Outlook 2010 is the best way to experience all that Exchange 2010 has to offer, feedback from the field has been very clear that many customers have longer client deployment cycles or are waiting for a desktop hardware refresh before upgrading clients.  Regardless of the reasons, customers running Outlook 2003 have seen their Outlook performance degrade with the removal of UDP support.

The Exchange product team has heard these requests loud and clear, and so this functionality will be re-introduced in Exchange Server 2010 Service Pack 1 Roll-Up 3 (SP1 RU3).  As a result, the RU3 schedule has been adjusted in order for the engineering team to complete the requisite work to include UDP support within the rollup, which is now expected to be released in March.

Additional Details:

You can find more details about how the removal of UDP notification support in Exchange 2010 affects the performance of Outlook 2003 users through Article 2009942 on the Microsoft Support page:

In Outlook 2003, e-mail messages take a long time to send and receive when you use an Exchange 2010 mailbox

If you are using Microsoft Office Outlook 2003 in online mode together with a mailbox that is located on a Microsoft Exchange Server 2010 server, you may notice the following symptoms:

  • Outgoing e-mail messages stay in the Outbox for up to 1 minute.
  • New e-mail messages do not arrive in the Inbox for up to 1 minute.
  • Items that are deleted from folders do not disappear from the folder for up to 1 minute.
  • Items that are moved from one folder to another folder take up to 1 minute to disappear from the original folder.

Generally, you notice that folder updates do not occur automatically in a timely manner.
When Outlook opens an initial connection to an Exchange server, Outlook tries to register itself to receive new message notifications. If Outlook can register for User Datagram Protocol (UDP) notifications, an Exchange server sends a notification to Outlook by using UDP when a new message arrives in the mailbox. When Outlook receives this UDP notification, Outlook retrieves the message from the Exchange server and displays the message in the appropriate folder. If Outlook does not receive new mail notifications through UDP, Outlook reverts to polling the Exchange server for changes. Although this polling behavior is initiated by Outlook, the Exchange server dictates the polling frequency. By default, Outlook performs polling every 60 seconds.

The problems that are described in this article occur because Exchange Server 2010 does not issue UDP notifications to Outlook. Therefore, Outlook cannot register to receive UDP notifications from Exchange Server 2010. Additionally, Outlook is not notified about changes that are made to a folder until Outlook polls the server for these changes. The default polling interval for Outlook is about 60 seconds. This is why you see delays that last approximately 1 minute in these folder actions.

Note This problem affects Outlook 2003 because it uses UDP as its primary method for receiving notifications from an Exchange server. Outlook 2007 is mostly unaffected by this problem because, by default, it uses an asynchronous notification process that does not rely on UDP notifications.

Online References:

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