The Role of the Network in Virtualization

Virtualization is becoming an increasingly important concept, not only to IT staffs, but to CIOs and line-of-business managers as well. Aspects of the "new economy" that contribute to the need for virtualization range from a globally distributed workforce of users who expect more control over when and how they work, to an increasing emphasis on service, worldwide competition, and the notion of the "borderless enterprise," where employees, customers, and partners share significant information and business processes. Another contributing factor is IT complexity involving power and cooling limits, low asset utilization, manual provisioning, inside and outside security, and Web-based applications.

To address these expansive changes, the IT infrastructure needs to evolve from an "accidental architecture" that delivers basic connectivity to silo'd departments with fortress-like barriers into an agile, resilient, and adaptive architecture that delivers service orchestration through integrated teams and service level agreements (SLAs) with enterprise-wide collaboration. IT then becomes a business unit that delivers services to improve the enterprise rather than burdening it as a cost center.

Evolving to a Service-Oriented Infrastructure
Virtualization is just one part of a multi-phase journey toward full automation and a policy-based, adaptive infrastructure. Organizations typically begin with some level of storage consolidation, data center consolidation, server standardization, and branch consolidation, all of which immediately contributes to improved asset utilization and efficiency. Virtualization has moved beyond the early adopter stage, especially in server virtualization, where companies are beginning to incorporate hypervisor technology into production systems and are experimenting with ways to use this technology to move applications transparently from one physical environment to another. According to Gartner, more than half the companies participating in 2007 IT infrastructure surveys were well along the infrastructure consolidation path. IDC concurs, predicting that virtualization will become a mainstream technology over the next few years.

At the same time, companies are recognizing the need for more advanced tools and processes to ensure that virtualization technologies can be implemented in production environments without increasing operational complexity. While virtualization brings many benefits, it also brings the IT staff new operational challenges. Service-orchestration solutions help address some of the challenges associated with maintaining separate physical and virtualization operational domains, while also easing the progression toward a more automated service-oriented infrastructure (SOI). (Figure 1)

Virtualization: Before and After
Let's examine a typical enterprise before it implements virtualization, where its choice is to share all or nothing. If a single physical application switch is used, applications must compete for resources, changes to one application can affect the others, and the device configuration is overly complex. Adding more physical switches creates an inefficient isolation of applications and results in device sprawl, under-utilized resources, and complexity in upgrading.

Conversely, with a virtualized architecture, abstraction and partitioning allow one physical switch to provide multiple virtual contexts, enabling isolated, secure applications with guaranteed resources and role-based access. This results in dramatic reductions in provisioning cycles, operating expenses (OpEx), and power requirements.

We can compare the evolution of data networking and the Internet with the new virtualized IT. In early data networking and wide-area communications, the problem was heterogeneous "network silos" comprising disparate transport and operating systems. The various protocols included ATM, FDDI, Ethernet, Token Ring, AppleTalk, Banyan Vines, Novell Netware, and DECnet that were costly, complex, and difficult to scale. Internet 1.0 delivered "information over IP" and provided a pervasive neutral medium with standard protocols for communicating globally and sharing information.

Similarly, within the enterprise, the problem is heterogeneous "infrastructure silos" - storage networks, applications, network equipment, servers, and interconnection technologies typically segmented by department or physical location - that are costly, complex, and difficult to scale. The solution is Internet 2.0, or "infrastructure over IP," providing a pervasive neutral medium, standard protocols, and built-in advanced capabilities for collaborating, sharing resources, and lowering costs.

Benefits of Virtualization
A significant advantage that comes with virtualization is reduced power consumption. Consider a typical enterprise that requires 10 Gbps load balancing, 20 Gbps firewall protection, 10 virtual contexts, and high availability. Using virtualized integrated modules that use approximately 11kW per hour, the enterprise will see an 85% reduction in power, providing more than $90,000 in OpEx savings over three years. Rack space is also reduced by nearly 30 rack units, with additional savings gained from reduced cabling, port consumption, and support costs.

Provisioning is also greatly simplified. To add one server to a Web farm in an existing silo'd infrastructure, multiple steps involving multiple departments and skill sets are required as illustrated in Figure 2. With any delay across the multiple layers of coordination, this simple expansion can take up to 90 days. New service turn-ups can stretch beyond 180 days. The "serial workflow" problem must be eliminated to streamline new service provisioning.

Automating infrastructure provisioning via the network uses virtual service templates and physical "pods" of servers, storage, and network equipment to accomplish the steps previously done by physical organizations and people. See Figure 3.

End-to-end service virtualization via the network pays off in several other ways besides reduced power consumption. Improved utilization, total cost of ownership (TCO), time savings, and flexibility are other benefits. For example, let's assume a traditional monolithic data center that experiences 25% year-over-year growth and 20% efficiency. In the second year of use, it will reach its power and capacity limits, suffer low asset utilization and escalating costs due to high operational overhead, and provide a low business value. Building a new data center can cost up to $250 million, plus an additional $25 million a year in operating expenses.

What happens when virtualization is deployed? Using metrics that Cisco discovered during its own data center redesign, utilization increases to 60% and lost capacity is regained. With virtualization, utilization rates increase dramatically, extending the life of the existing data center an average of four-and-a-half years. The average cost to maintain a new data center is $40 million a year, so over that period of extended life, savings will grow to $180 million. Other benefits become apparent as well, including the deferral of purchasing new capacity, improved asset utilization, better power efficiency, and lower TCO.

Phased Implementation
An enterprise committed to moving to a service-oriented network infrastructure will achieve the greatest success by following a phased approach that allows for gradual consolidation and virtualization, leading to the ultimate goal of automation. Figure 4 outlines the key elements of this phased approach.


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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