A service view before Web services
The name "Web services" requires enterprises to relate the concept of a service to the current IT architecture. Meta Group research has found three basic service categories for the infrastructure: application (e.g., authentication and authorization), technical (e.g., storage and LAN), and operational (e.g., help desk and project services). These services are inter-related and require a tightly focused planning team from the respective areas (e.g., applications, infrastructure and operations) to ensure the architecture successfully incorporates this infrastructure view. IT organizations will discover during this planning process that application services are actually infrastructure services, because they separate service consumers from providers and define functional and service-level application interfaces when planned properly. The goals during this planning are minimizing application/infrastructure coupling and infrastructure instances, maximizing service sharing, and enabling the introduction of utility-grade technical and operational service providers, where necessary.

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It's all about the interfaces
Web services network architecture builds on the harsh lessons learned from object-oriented architecture. For Web services, the unit of composition is not defined via an application programming interface, but as a pattern of interactions between providers and subscribers and the information exchanged during those interactions (i.e., protocols and formats). Internet services are an early form of this approach, because they are defined as protocols and formats (e.g., IP and FTP). Although previous architectures (e.g., COM and J2EE) emphasize the logical separation of interface and implementation, they have been unsuccessful at reducing interface complexity enough to avoid "rebuilding" application components. Web services propose to decouple service use and implementation by separating them over a network. Although this results in an agile service-oriented architecture, it raises questions regarding the inevitable impact such implementations have on existing network architectures.

The networkability of Web services
E-business networking lessons drove the introduction of new component technologies and services to improve the quality of experience. Those technologies and services are now considered by most enterprises to be a normal part of networking infrastructure. Initial Web services applications exhibit transaction and messaging packet sizes that are not optimized for current network configurations. Large-scale Web services will encourage a reconfiguration and tuning of these services (e.g., caching, compression, traffic shaping, and content hosting) to accommodate existing patterns of infrastructure, and accelerate the delivery of application-level quality-of-service capabilities from service providers and networking equipment vendors. Vendors such as Packeteer, NetReality, Expand Networks, Chutney Technologies, and Forum Systems are already evaluating potential upgrades to traffic shaping, compression, caching, and security technologies, while new and existing vendors within the router, switching, and firewall markets are contemplating the impacts of Web services traffic.

Infrastructure and network planners should begin now to evaluate Web services architecture variations as delivered or proposed by major application development vendors (i.e., Microsoft, Sun, and IBM) to assess potential network choke points prior to implementation. Application planners should invite network operations to participate fully in pilot tests of Web service applications to ensure that network capacity and performance data is captured for analysis. Enterprises already developing budgets for Web services should include provisions for potential network infrastructure upgrades to precede such deployments as insurance.

Business impact
A new services-oriented view of infrastructure is required to ensure a successful long-term transition to effective Web services for the enterprise.

Bottom line
IT organizations intent on leveraging the promise of Web services should converge existing component and service mappings of adaptive infrastructure with Web service mappings, while standardizing on a small set of large-scale services where possible.

Building the Infrastructure for Web Services
First published on July 8, 2002.
By Earl Perkins

Have your network planners taken Web services into consideration? TalkBack below or e-mail us with your thoughts.

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