WCF throttling provides some properties to limit how many instances or sessions can be created at the application level. Performance of the WCF service can be improved by creating proper instance.
Throttling is having three specific attributes to define the values. They are,
1. maxConcurrentCalls: Limits the total number of calls that can currently be in progress across all service instances. The default is 16.
2. maxConcurrentInstances: The number of InstanceContext objects that execute at one time across a ServiceHost. The default is Int32.MaxValue.
3. maxConcurrentSessions: A positive integer that limits the number of sessions a ServiceHost object can accept. The default is 10.