Design Considerations
Design chunky interfaces to reduce round trips.
Prefer message-based programming over remote procedure call (RPC) style.
Use literal message encoding for parameter formatting.
Prefer primitive types for Web service parameters.
Avoid maintaining server state between calls.
Consider input validation for costly Web methods.
Consider your approach to caching.
Consider approaches for bulk data transfer and attachments.
Avoid calling local Web Services.
Connections
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Configure the maxconnection attribute.
Prioritize and allocate connections across discrete Web services.
Use a single identity for outbound calls.
Consider UnsafeAuthenticatedConnectionSharing with Windows Integrated Authentication.
Use PreAuthenticate with Basic authentication.
Threading
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Tune the thread pool using the formula for reducing contention.
Consider minIoThreads and minWorkerThreads for intermittent burst load.
One Way (Fire and Forget) Communication
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Consider using the OneWay attribute if you do not require a response.
Asynchronous Web Methods
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Use asynchronous Web methods for I/O operations.
Do not use asynchronous Web methods when you depend on worker threads.
Asynchronous Invocation
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Consider calling Web services asynchronously when you have additional parallel work.
Use asynchronous invocation to call multiple unrelated Web services.
Call Web services asynchronously for UI responsiveness.
Timeouts
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Set your proxy timeout appropriately.
Set your ASP.NET timeout greater than your Web service timeout.
Abort connections for ASP.NET pages that timeout before a Web services call completes.
Consider the responseDeadlockInterval attribute.
WebMethods
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Prefer primitive parameter types.
Consider buffering.
Consider caching responses.
Enable session state only for Web methods that need it.
Serialization
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Reduce serialization with XmlIgnore.
Reduce round trips.
Consider XML compression.
Caching
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Consider output caching for less volatile data.
Consider providing cache-related information to clients.
Consider perimeter caching.
State Management
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Use session state only where it is needed.
Avoid server affinity.
Attachments
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Prefer Base64 encoding. Direct Internet Message Encapsulation (DIME) is a supported part of Web Services Enhancements (WSE), but Microsoft® is not investing in this approach long-term. DIME is limited because the attachments are outside the SOAP envelope.
COM Interop
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Avoid single-threaded apartment (STA) COM objects.
