There are many facts in WCF which can impact the concurrency performance of a service. For example, the maximum number of instances that can be activated concurrently, the maximum number of sessions that can be active concurrently, and the maximum number of service operation calls that can be executed simultaneously. If configured incorrectly or in a bad manner, it is possible that our service might encounter a performance bottleneck or suffer a DOS attack in an unpredictable internet environment.
Fortunately, WCF also provides sufficient built-in configuration options for developers to control these concurrency-specific behaviors of the running service. This recipe will introduce the Throttling