Service-Oriented Network Architecture
A crucial element of transforming an enterprise from a legacy silo'd infrastructure to a service-oriented infrastructure is the use of an architectural framework to guide the implementation. Cisco's Service-Oriented Network Architecture, or SONA, is a framework that details a set of common services that are deployed in the network to close the resource and application gaps described previously. As such, SONA describes how to build an intelligent information network in the enterprise. (Figure 5)

SONA consists of three layers: the network systems layer, the integrated network services layer, and the application layer.

At the bottom, the networked infrastructure, or network systems layer, represents the capital infrastructure of the IT environment, including the routing and switching infrastructure, storage, servers, and devices. Many of the services described below are hosted on these devices, either in software or add-on blades. In the SONA framework, there's a separate set of architectures, blueprints, configuration guidelines, and case studies for campus, data center, and branch locations.

The integrated network services layer optimizes communications between applications and services by taking advantage of distributed network functions such as continuous data protection, multi-protocol message routing, embedded quality of service, I/O virtualization, server load balancing, SSL VPN, identity, location, and IPv6-based services. There are three categories of services in this layer:
1.  Infrastructure services, which are the "downward-facing" services that help to close the resource gap described earlier. This category includes security, mobility, storage, voice, and collaboration, computational, identity, and network infrastructure virtualization services. These services enable organizations to optimize the effectiveness of their infrastructure and facilitate the allocation of the right resources to the right business processes and applications. A key common technology employed in many of these services is virtualization. Virtualization has two axes: the ability to make many resources look like one (or one to look like many) and the ability to deal with resources on a logical, as opposed to physical, basis. Historically, the network has been a crucible for virtualization, and this is now being extended from network resources to other IT resources such as servers and storage.

2.  Application services are the "upward-facing" services that enable application integration, delivery, scale, and optimization through network-based services. This category has two major components: Application-Oriented Networking (AON) and application delivery. AON lets the network speak the language of applications: for example, messages such as a purchase order. This lets the network intelligently act to route, transform, log, notify, or validate business-level objects. Because most applications weren't designed with network optimization in mind, adding application delivery services in the "horizontal" network framework enables the end-to-end delivery, scale, and optimization of application data and control information across the enterprise and among users, suppliers, and partners.

3.  Adaptive management services consist of three components: infrastructure management (the automated management of collections of devices), services management (the management of integrated services), and advanced analytics and decision support. These management services are implemented through APIs to other parts of the infrastructure to enable the network to share policy and control information across all of the layers of the IT infrastructure.

The applications layer is divided into two categories: collaborative applications that enable communication and collaboration, and business applications such as CRM (customer relationship management), ERP (enterprise resource planning), and SCM (supply chain management). Through the common services provided by the integrated services layer, the network now plays a direct and critical role in enabling these applications (and their resources) and their associated business processes.

Finally, let's look at how SONA relates to Service-Oriented Architecture. SOA is an approach to application design, integration, and delivery that enables the reuse of applications and significantly reduces integration costs. This is done through modules based on business services with loosely coupled business logic, compared to the monolithic, tightly coupled applications that predominate today. SONA complements SOA by enabling a services-oriented infrastructure. By deploying Cisco's SONA today, organizations can reap immediate benefits from a more effective and efficient IT infrastructure. By deploying these new application and resource services, enterprises lay the groundwork for evolving to SOA.

Conclusion
The network is a uniquely qualified IT resource to enable virtualization, providing a pragmatic adoption path toward service-oriented infrastructure and SOA. Using the SONA framework, organizations can reap the benefits of end-to-end virtualization and policy-driven service orchestration. This shared services architecture enables flexibility and agility while streamlining resources and reducing operational expenses. (See Sidebar)

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