2.1 Transport
Protocol servers MUST support SOAP over HTTP. Protocol servers SHOULD additionally support SOAP over HTTPS for securing communication with protocol clients.
Protocol messages MUST be formatted as specified in [SOAP1.1] section 4. Protocol server faults MUST be returned either using HTTP status codes as specified in [RFC2616] section 10 or using SOAP faults as specified in [SOAP1.1] section 4.4.