2. The IT DialTone Infrastructure

2.1 Role of the IT DialTone Infrastructure

Figure 2.1 - The Role of the IT DialTone Infrastructure

In conceptual terms, the role of the IT DialTone Infrastructure is simple, namely to encompass all of the IT services which bridge between the physical domain,   facilities, computers, networks etc. and the business domain, the applications which embody the business processes of the enterprise.

To do this, the IT DialTone Infrastructure must include mechanisms to implement the policies of an enterprise, in particular security and management.

2.1 Overall Structure of the IT DialTone Infrastructure

The way that The Open Group is defining the IT DialTone infrastructure reflects the two distinct objective:

• The need to reduce the level of complexity that an IT user needs to handle and to enable the level of investment in business applications to be increased
• The need to plan for a global integrated infrastructure without imposing on early pioneers the costs of major reengineering

Figure 2.2 - The structure of the IT DialTone Infrastructure

2.2 The IT DialTone Core Infrastructure

To achieve global interoperability, the infrastructure is based on the comparatively simple IT DialTone Core Infrastructure.

This core communications capability, the backbone upon which the rest of the IT DialTone infrastructure is built, is the single item which differentiates the IT DialTone initiative.

• To achieve global interoperability, the IT DialTone Core Infrastructure must be ubiquitous. That means that it must be the same everywhere and anything that uses it must understand completely the structure of the data and information being exchanged. Unlike previous attempts to develop a vendor independent standard communications capability, the IT DialTone Core Infrastructure will not contain multiple conflicting options. If there is more than one way defined to carry out a particular function, then all implementations must support all of the multiplicity.
  
• To achieve interoperability, the IT DialTone Core Infrastructure does not need to define the totality of IT. As with the necessary agreements to enable a network of railways to be created, there is a constrained, core set of capabilities that need to be done in a consistent manner. The IT DialTone Core Infrastructure needs to be able to deliver a piece of information to the right destination, securely, reliably and within a predictable period of time.
  
• To define interoperability, the IT DialTone Core Infrastructure is concerned with the structure of the information that is flowing around a network, not with the way in which applications cause that information to flow. That means it is totally defined in terms of protocols and data structures.
  
• It is only necessary for the IT DialTone Core Infrastructure to define data structures. It does need to define the application semantics and information content carried within the agreed structures.

2.3 IT DialTone Application Environments

The second element of the IT DialTone initiative addresses the needs of CIOs to be able to deploy business applications.

Building on the ubiquitous backbone established by the IT DialTone Core Infrastructure, IT DialTone Application Environments define all of the distributed computing services necessary to support business applications that want to communicate using the IT DialTone Core Infrastructure.

There is no tolerance whatsoever for diversity in the IT DialTone Core Infrastructure. Diversity is disastrous when trying to achieve global interoperability. There is however, some tolerance for multiple IT DialTone Application Environments. Even though different applications are using different programming interfaces in different environments, providing that they use the same communication protocols interoperability is not affected. The major impact of this lack of application portability is increased cost.

It is clearly desirable to reduce the number of different application environments, but in the foreseeable future, it will not be practical, nor even desirable to aim for a single one.

• Application environments are often tied to a particular computer platform architecture (although as the level of standardization rises, this is becoming less and less significant)
  
• There are almost as many application environments as there are enterprise customers. Each application comprises a common set of functionality, that which is specific to a particular segments of the market and that which is specific to a single enterprise. (As IT evolves, the proportion which is common is growing and that which is enterprise specific is falling).
  
• New approaches to application development often manifest themselves in terms of new application environments, which retain interoperability with older applications through adherence to standard interoperability protocols.

The IT DialTone initiative will define a number of different IT DialTone Application Environments, but will highlight how the different pieces fit together and what interdependencies there are, and will identify the areas where divergence cannot be tolerated even at the Application Programming Interface level.

From figure 2.1 above, it would be easy to equate the term IT DialTone Application Environment with a single computer. That would be incorrect. Open Systems computing is rather like a jigsaw puzzle with blank pieces. What is important is how the pieces join together, not the internal designs on each piece. The defining characteristics of an IT DialTone Application Environment are a standard set of application interfaces and external communication using the IT DialTone Core Infrastructure.

A single IT DialTone Application Environment may encapsulate a complete multiple computer system distributed computing environment which uses a different set of communication protocols internally.

2.4 IT DialTone Distributed Applications

Another inference that could be drawn from figure 1.2 is that the IT DialTone addresses only applications implemented on a single IT DialTone Application Environment. That too would be incorrect.

Figure 2.3 - IT DialTone Distributed Applications

The IT DialTone Infrastructure is being designed upon the premise that all applications are distributed applications, which operate through the co-operation of application components deployed across a distributed system.

To that end, IT DialTone Application Environments all contain features to integrate distributed software components and to manage the flow of information between them.

2.5 Network Computer Profile - A Universal Client

The first fully defined IT DialTone Application Environment is the Network Computer Profile.

Initially intended as the basis for the development of standard "thin client" network computer devices, the final Network Computer Profile is much more than that:

• It does define the minimum capabilities of a diskless network computer
• The same capabilities can, however be deployed on virtually any personal computer or workstation

Figure 2.4 - The IT DialTone Universal Client

The Network Computer Profile defines a standard IT DialTone client with:

• Full support for the IT DialTone Core Infrastructure
• A core set of user interface capabilities built in
• A JAVA application environment which can used for the deployment of additional application components in a completely platform independent manner

2.6 Integrating the Enterprise

A recent study carried out by IDC highlights that lack of access to information tied up in so-called heritage systems is a major barrier to the growth in use of internet technologies.

In order to succeed, the IT DialTone initiative must provide facilities for exploiting the considerable value of the applications and systems implemented on enterprise system servers.

There are a number of ways in which this can be achieved:

Perhaps the best known of these is through a gateway system which understand both the heritage infrastructure and the IT DialTone Core infrastructure:

Figure 2.5 - The Enterprise Gateway

Gateways are a popular and effective way to bridge between two incompatible systems. However, they are often performance bottlenecks and their capability is constrained by the functionality that is supported by both infrastructures. For example, current gateways presenting a WEB form as an interface to a mainframe application are not able to provide transactional behavior.

Figure 2.6 - The IT DialTone Aware Enterprise Server

Performance problems can be addressed by making the enterprise server system aware of the IT DialTone Core Infrastructure .. effectively embedding the gateway within the enterprise server and taking advantage of services there to improve performance.

Figure 2.7 - Exploiting the universal client

Both the performance constraints and the mismatch of functionality between the two systems can be addressed by taking advantage of the capabilities of the universal IT DialTone Client.

After an initial interaction using only the capabilities of the IT DialTone Core Infrastructure, the enterprise system can download to the client a protocol module written in JAVA which allows that client to interact with the enterprise system use heritage system protocols. If the heritage system supports security, then the client-server interaction can utilize that security, if the heritage system supports transactional behavior then the client-server interaction can implement transaction behavior.

The only restriction on the applicability of this approach is the need for the heritage protocols to be carried on the same transport as the IT DialTone Core Infrastructure.

To be clear, the heritage environment is not part of the IT DialTone Infrastructure, but the capability to support any infrastructure through downloaded protocol modules is.