Cisco Cisco CRS-X Multishelf System Weißbuch
White Paper
© 2008 Cisco Systems, Inc. All rights reserved. This document is Cisco Public Information.
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Router Virtualization in Service Providers
Executive Summary
Several factors are contributing to a growing need for virtualization in the point of presence (POP)
and data center: a desire to reduce capital costs by buying fewer chassis, a desire to reduce
operational costs by deploying fewer chassis and simplifying topologies, and a strong push to
decrease the environmental impact by using less power. These goals must coincide with existing
requirements of stability, resiliency, and service isolation. This paper discusses how the needs of
POP deployments compare and contrast with those of the data center and which virtualization
architectures are available to address those needs. It then covers the architectural benefits of
virtualization in Cisco
®
IOS
®
XR Software that contribute to these goals.
Deployment Considerations
Historically, virtualization occurs much more frequently in the data center than the POP because of
cost savings and overlapping administrative domains. However, environmental concerns and
recent architectural advances have expanded the possible range of virtualization opportunities
outside the data center. High-end routers require substantial power and cooling just for the basic
chassis components, so any virtualization can provide a significant power savings by simply
adding hardware components to existing equipment. The following sections will analyze two key
deployment scenarios – POP and data center – and evaluate the requirements of each.
Data Center
Virtualization in the data center traditionally refers to applications and application servers, such as
HTTP and SAP. Because rack space is such a precious resource, adding extra servers and routing
instances without an increase in rack space is highly desirable. Space and power are more
expensive because typically a third party, not the company deploying the equipment, owns the
facilities. Figure 1 provides a typical virtualization topology in a data center environment.