 WCF runs in a sandbox and provides the enhanced security model all .NET applications provide.WCF is capable of using SOAP for communication between two processes, thereby making WCF based applications interoperable with any other process that communicates via SOAP.When a WCF process communicates with a non-WCF process, XML based encoding is used for the SOAP messages but when it communicates with another WCF process, the SOAP messages are encoded in an optimized binary format, to optimize the communication.