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Web service technology must be based on generally accepted standards. When you build your environment using Web services, you link up application modules developed in different programming languages on different hardware and in different systems with the business process. As soon as you do this, you are faced with the important questions of interoperability and adherence to prescribed standards.

Conventional Internet standards are used for communication. The interface of a Web service is specified using WSDL, remote procedure calls are transmitted using SOAP, and Web services are determined using UDDI.

Although standards such as SOAP, WSDL, and UDDI became the general norm, there is still much to be accomplished by standardization committees. The committees develop some new standards and update other standards. SAP continuously updates and integrates the enhanced standards - such as security standards or additional protocols - into the Web Service Framework.

General Web Service Specifications

  • SOAP (1.1 and 1.2)

    Simple Object Access Protocol (SOAP), provides the definition of the lightweight protocol for XML based information, exchanged between parties in a distributed environment. SOAP version 1.2 supports major features, required for communication with other Web service vendors.

  • WSDL (1.1)

    Web Service Description Language (WSDL), describes Web services as abstract endpoints operating on messages. The definition of operations and messages is abstract while the binding to a specific network protocol is concrete.

  • UDDI (3.02)

    Universal Description, Discovery and Integration (UDDI), defines a uniform way of publishing and discovering Web services.

  • WS-I Basic Profile (1.1)

    Provides interoperability guidance for core Web services specifications such as SOAP, WSDL, and UDDI.

  • XML (1.0)

    Extensible Markup Language (XML), a self-descriptive language designed for exchanging structured data over the Internet. It is the foundation of Web services.

  • HTTP (1.1)

    Hyper Text Transfer Protocol (HTTP), a lightweight document transfer protocol that provides an effective universal data transfer.

Description and Discovery Specifications

  • WS-Policy (1.2)

    Defines the model and syntax to describe and communicate the policies of a Web service. A policy is a collection of policy assertions which describe one or more characteristics that a Web service provider requires from a Web service consumer to follow.

  • WS-Policy Attachment (2004/09)

    Defines how to attach WS-Policy assertions to WSDL documents and UDDI descriptions.

    Support Details: Only attachment to WSDL 1.1 is supported

  • WSIL (1.0)

    Web Service Inspection Language (WSIL), defines how to locate Web service descriptions on a provider system.

  • WS-MetadataExchange

    Defines how endpoints can request the various types of metadata they may need to effectively communicate with the Web service.

Messaging Specifications

  • WS-Addressing (1.0)

    Defines a standard mechanism for identifying and exchanging Web services messages between multiple endpoints.

  • WS-ReliableMessaging (1.1)

    Describes a protocol that allows messages to be delivered reliably between distributed applications in the presence of software component, system, or network failures.

    The following scenario is supported: anonymous client and one-way operations.

    The following scenarios are not supported:

    • Anonymous client and request-response operations.

    • Addressable client and one-way operations.

    • Addressable client and request-response operations.

  • MTOM

    The SOAP Message Transmission Optimization Mechanism allows more efficient sending of binary data in a SOAP request or response.

Security Specifications

  • WS-Security (1.0 and 1.1)

    Describes extensions to SOAP that allow for quality of protection of SOAP messages including binary tokens for message authentication, digital signatures for message integrity, and content encryption for message confidentiality.

  • WS-Security: SAML Token Profile (1.1)

  • WS-Security Policy (1.2)

    Defines security assertions detailing a Web service's requirements that the Web service consumer can meet.

    Support details: WS-Security Policy is available in PI 7.1 only for SAP to SAP scenarios.

  • WS-SecureConversation (1.3)

    Defines how to establish and maintain a persistent context for a secure session over which multiple Web service invocations might be sent without requiring authentication each time.

    Support details: WS-Secure Conversation is available only for SCT over SSL bootstrap

  • SAML (2.0)

    Security Assertion Markup Language (SAML) is an XML based standard for exchanging security information between systems.

  • WS-Trust (1.3)

    WS-Security defines the basic mechanisms for providing secure messaging. WS-Trust uses these base mechanisms and defines additional primitives and extensions for security token exchange to enable the issuance and dissemination of credentials within different trust domains.