Exchange web service API autodiscoverurl takes too long

Question

We have an aspx page that uses the Exchange Web Service API to access our Exchange Server 2010 system. The application retrieves reservations and displays the reservations on mobile devices. The application works fine except that the call to the AutodiscoverUrl() method takes a long time, up to 20 seconds.

We moved this call to the Application start so that it needs to occur only once in a while, usually for the first user of the day. But, I would still need to determine why this call takes so long. Does anyone have any thoughts on how to speed up this call?

Thanks,

jerry

Answer 1

This may be too obvious for the "why": Because it's doing a lot under the hood when you call the method, including making network connections, which are performance-intensive.

http://msdn.microsoft.com/en-us/library/bb204047%28EXCHG.140%29.aspx

This article provides a lot more informaiton, AND something helpful if this is an in-house process. (Italics added to help you find the performance section).

http://msdn.microsoft.com/en-us/library/ee332364(EXCHG.140).aspx

Discovering the Autodiscover Endpoint via Active Directory SCP Record Lookup

For applications that run on-premise (that is, from a computer that has access to the company's Active Directory Domain Services or Active Directory directory service), SCP record lookup is a secure way to discover the Autodiscover endpoint without Autodiscover having to be accessible from the Internet. It is secure in the sense that URLs that are found in the Active Directory database can generally be trusted, for the following reasons: The URLs were configured by a trustworthy source (the Exchange administrator).

The application has to authenticate against the Active Directory server to be able to query it.

Because URLs that are discovered via SCP lookup are trustworthy, a client application does not have to validate the certificate that is presented by the server. As long as a certificate exists, the application can send a POST request to the endpoint.

Although we generally recommend that customers buy and deploy valid certificates, the Exchange installer by default installs self-signed certificates on Autodiscover virtual directories. For this reason, performing an SCP record-based discovery of the Autodiscover endpoint is a great way to support an out-of-the-box Exchange installation that improves the end user experience by removing the need for a security prompt.

Another benefit of SCP lookup is that it helps distribute Autodiscover load. Because SCP URLs are scoped to Active Directory sites (as described in the section “Performing SCP Record Lookup” later in this article), it is possible for administrators to force Autodiscover clients to connect to servers that are dedicated to the site they are running in. Using URLs discovered via SCP lookup also reduces connection latencies and thus improves overall performance, because clients are connecting to servers that are in closer proximity to them.