Information Technology Reference
In-Depth Information
This chapter covers general enterprise data center considerations that you need to master
for the CCDA exam. It star ts w ith a dis c u s s ion of the enter pr is e data center architec t ure
and how we have evolved from Data Center 1.0 to Data Center 3.0. The section “Data Cen-
ter 3.0 Components” covers the virtualization technologies and services that unify net-
work, storage, compute, and virtualization platforms. The section “Data Center 3.0
To p o l o g y C o m p o n e n t s ” s h o w s h o w t h e v i r t u a l i z a t i o n t e c h n o l o g i e s i n t e g r a t e w i t h u n i f i e d
computing and the unified fabric.
The “Challenges in the Data Center” section describes the common server deployment
challenges present in the data center. Major facility aspect issues involving rack space,
power, cooling, and management are covered. Data center cabling is examined along with
the data center cable considerations critical to the proper cable plant management.
Follow ing that, the “Enterprise Data Center Infrastructure” section explores the Cisco
multilayer architecture that is used for building out enterprise data centers to support
blades servers, 1RU (rack unit) servers, and mainframes. Design aspects of the multilayer
architecture involving data center access layer, aggregation layer, and core layer design
considerations are also covered.
The chapter wraps up with several sections on virtualization. An overview of virtualiza-
tion is covered along with key drivers that are pushing the adoption of virtualization in the
data center. The section “Virtualization Technologies” compares the two main types of
virtualization and provides several examples. Then the section “Network Virtualization
Design Considerations” covers access control, path isolation, and services edge.
Over the past two decades, we have seen an evolution of data center “architectures”. With
Data Center 1.0, data centers were centralized, using mainframes to process and store data.
The users of Data Center 1.0 used terminals to access and perform their work on the main-
frames. Mainframes are still prevalent in many data centers because of the overall benefits
in terms of availability, resiliency, and service level agreements (SLA).
Figure 4-1 illustrates the evolution of data center architectures from Data Center 1.0 to
Data Center 3.0.
Data Center 2.0 brought client/server and distributed computing into the mainstream data
center. Business applications were installed on servers and were accessed by users with
client software on their PCs. Application services were distributed because of high cost of
WA N l i n k s a n d a p p l i c a t i o n p e r f o r m a n c e . A l s o , t h e c o s t s o f m a i n f r a m e s w e r e t o o c o s t l y t o
be used as an alternative for client/server computing.
Currently, we are moving away from Data Center 2.0 and toward Data Center 3.0, where
consolidation and virtualization are the key components. The cost of communication
equipment is lowering, and there is an increase in computing capacities, which is driving
effective when compared to the distributed approach. The newer architecture takes
