WCF supports four types of hosting, They are as follows,
1. IIS hosting
2. Self hosting
3. Windows service
4. WAS (Windows Activation Service)
1. IIS hosting: IIS (Internet information services) will take care of several features like process recycling, idle shutdown, process health monitoring and message based activation. It will automatically launch the host process when it gets the first client request.
2. Self hosting: Self hosting gives option to developer to develop a self program to manage the life cycle of host process.
3. Windows service: Like hosting WCF in IIS or as Self hosting, WCF can be hosted in windows service also. The service will be hosted, when system starts and process life time of the service can be controlled by Service Control Manager for windows service.
4. WAS (Windows Activation Service): Windows Activation service is a system service available with Windows vista and windows server 2008. It is available with IIS 7.0 and it supports Http, TCP and named pipes were IIS 6.0 supports only Http. It can be installed and configured separately. Hosting WCF in Activation service takes many advantages such as process recycling, isolation, idle time management and common configuration system.