What is AS4?

Overview

AS4 (Applicability Statement 4) is a message protocol based on web services to securely exchange B2B messages between trading partners. The protocol was developed by the technical committee of OASIS (Organization for the Advancement of Structured Information Standards) for ebXML Messaging Services. AS4's web services capability gives it the opportunity to develop into a cloud-based communication standard.

Comparison AS2 and AS4

AS4 and AS2 are very similar by design. During the development of AS4, all advantages of AS2 were analyzed, worked out and inspired by them. In contrast to AS2, AS4 works within a web service context and also has better interaction patterns and delivery notifications. In addition, compared to AS2, AS4 has the option of actively pulling messages by the recipient, since the AS4 server is permanently active.

Main features of the AS4 messaging standard:

• Interoperability: The AS4 messaging standard is defined based on the OASIS standard
• Security: A subset of web services security features is used to ensure the non-repudiation of the message and data confidentiality.
• Reliability: by exchanging confirmations, AS4 ensures a one-time delivery
• Independence from use: any type of payload (EDI, XML, ...) can be exchanged

AS4 Messaging Service Handler

The Messaging Service Handler (MSH) is responsible for setting up the AS4 message exchange with the remote station on the sending or receiving side. Communication with the remote station must comply with AS4 specifications and be able to communicate with an internal business application.

Message types of AS4

The ebMS 3.0 specification defines the following message types defined within the AS4 usage profile:

• User Message: contains the business payload that is exchanged between the business applications of two parties
• Signal Message: have the function of establishing non-repudiation and reliability. There are three different types:<
   
  1. Receipt
     Confirmed that the received MSH could analyze the incoming message
      
  2. Error
     Confirms that the received MSH encountered a problem while parsing the incoming message.
      
  3. Pull request
     Supports the pull message exchange pattern.

What are the general advantages of AS4?

• The source is clearly defined by digital signatures
• Data security through encryption is secured
• Proof of timely delivery by delivery notification receipt
• Support for large file compressions and file transfers

The areas of use of AS4

AS4 is increasingly being used in markets that use a service-oriented architecture for B2B messaging. These include the retail trade, the health sector and the utilities sector.

For example, the European gas network operators (ENTSOG) have already defined their own usage profile in 2015. Other uses that rely on AS4 include:

• Europe: 
  • Peppol (Pan-European Public Procurement Online)
  • e-CODEX (e-Justice communication via online data exchange)
  • ENTSOG (European Network of Transmission System Operators for Gas)
  • EPREL (European Product Registry for Energy Labelling)
• Japan: JEITA (Japanese Association of Electronics and Information Technology Industries)
• Australia: Superstream Pensions
• Worldwide: ATA (International Air Transport Association)

Learn more about how SEEBURGER AG offers its customers an AS4 gateway for various purposes.