Ethical issues in Web services: a layered approach

Laurette Pretorius and Andries Barnard


Modular design and analysis approaches proliferate in computing, and in particular in software design. Layered approaches also belong to this paradigm. The ethical discussion and analysis of software designs and implementations, and of software artefacts for solving real problems may also benefit from such inherent structure. In particular we briefly review an appropriate layered approach, the extended OSI model for Internet-based computing, which has been the subject of ethical discussion (Gleason and Friedman, 2004). We also summarise the modelling of Web services as a protocol stack consisting of six layers (Jeckle and Wilde, 2004) for the purposes of an ethical discussion thereof.

The purpose of the somewhat technical discussion of the layered approaches is to contextualise and to focus the ethical discussion and may be justified as follows: In computing the whole point of modularity, and in particular layeredness, is that it facilitates the identification (and isolation) of functionality and its associated issues (and problems). The idea is that by resolving the individual “simple” issues, the more complex system that is built out of the different modules would be easier to design and validate. We are of the opinion that this modularity, which is usually based on (computational) functionality and allows system designers to focus on one issue at a time, will also be of significance in the ethical analysis of computationally complex systems. In this paper we subject each layer of this model to an ethical discussion appropriate for the specific layer on the basis of its associated functionality.

At the core of cyberspace are the physical components and attributes that facilitate interconnectivity. Theoretically the Open Systems Interconnection (OSI) model is a comprehensive representation of what happens between two nodes on a network. This model divides networking architecture into 7 layers; viz. the Physical, Data link, Network, Transport, Session, Presentation, and Application layers (Dean, 2000). Gleason and Friedman (2004) argue that the OSI model is an accessible and descriptive model of cyberspace that enables an extension of this model in order to focus on humanistic and ethical issues. They propose three additional layers “to elucidate the human side of the equation”. These three layers are the user interface, interpretation and impact layers.

The Web services paradigm of computing has become a de facto standard in Internet computing. Indeed, the “Gartner Group predicts that by 2004 Web services will dominate deployment of new application solutions for Fortune2000 companies, and companies that fail to adopt this technology will find themselves at a competitive disadvantage” (Beyond Integration, 2003).

It so happens that the Web Services paradigm of Internet computing still (in 2005) continues to grow in use and popularity. Moreover, it may be conceptualised as a layered approach where each layer has it own functionality, as given below. What we are aiming to do, is to exploit this modularity in order to focus on the particular ethical issues of each individual layer separately. This approach allows us to appropriately apply different ethical theories/analyses/approaches to different layers. As a first step we focus on each layer individually, but it would certainly be interesting to explore the ethical interconnections/dependencies between neighbouring layers as well. The latter investigation falls outside the scope of this paper, but is the subject of future work.

Jeckle and Wilde (2004) propose a six layered protocol stack to provide a conceptual understanding of Web services application artefacts in general. The idea behind Jeckle and Wilde’s (2004) proposal is to cluster related functionally in a horizontal manner, thus constituting separate layers.

The first layer, the underlying protocol layer, provides transport mechanisms such as, for example, HTTP and TCP. The second layer, the URI, XML and SOAP layer, is responsible for reliably transmitting data between two communication peers that are connected through a first layer infrastructure. At the next layer, the addressing and routing layer, the logical connections for communication are provided. The fourth layer is the security and message pattern layer, which sets out a collection of message patterns that define the sequence and cardinality of abstract messages, which can be applied to every communication protocol, e.g. SOAP. Session management essentially constitute the basis of layer 5, the coordination layer. Potential candidates for this layer include BPEL4WS and WS-Choreography (Jeckle and Wilde, 2004). The sixth layer, the vocabulary layer, is responsible for mapping the application’s data model into a form that can be transmitted between communicating peers. In the Web services world XML Schema accomplishes this.

In summary, the main focus of our paper is to consider ethical issues and/or perspectives that arise at the various layers of the Web services protocol stack of Jeckle and Wilde (2004). We base our discussion on some recent computing ethics initiatives, among others, disclosive computer ethics (Brey, 2004), information ethics (Floridi and Sanders, 2003 and 2004) and the ethics of surrogate agents (Johnson and Powers, 2004). We explore their applicability to the individual layers within their various contexts as presented by (Jeckle and Wilde, 2004).


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