Now a days almost every engineer in “Traditional” Networking
industry hears term Virtualization. While some engineers vaguely understand how
virtualization relates to L2 switches/L3 switches / Blade Switches/ protocols
that they work upon while some do not. This post is an attempt to explain how virtualization
(specifically server virtualization) industry impacted existing networking
arena and what problems did it rise in current Networking setup. 
What is
Virtualization, Server Virtualization? What will it fetch?
Well – virtualization can take many forms while
virtualization that is most prominent and relevant to networking industry is Server
Virtualization (SV). Let me just take
some space to explain what is SV and why it is needed. Business applications of
an organization need support of servers in order to automate its business.
These servers are normally maintained by IT wing of organization. Typically
these servers are x86 servers which cost companies quite a money in terms of
real-estate, power and technical expertise. Virtualization
has evolved to software technology that is helping to transform the IT
landscape and fundamentally changing the way people utilize computing
resources. Today’s powerful x86 computer hardware, which was designed to run a
single OS and a single application, is being vastly underutilized in this
capacity. One solution to this underutilization involves a type of virtualization
that allows users to run multiple virtual machines on a single physical
machine, thereby sharing the resources of that single computer across multiple
environments. Within IT data center environments, server virtualization has
been getting most of the attention because of the many benefits associated with
it. Server virtualization is a concept where one physical machine is divided
into many virtual servers. The main incentive for IT organizations to use this
technology is that many of the servers across the enterprise are underutilized,
based on the existence of multiple processors, lots of memory, and huge amounts
of disk space. By adopting server virtualization, IT organizations can then
consolidate multiple servers into a single physical server, thereby reducing
the number of physical servers required by optimizing the resources of the one
server
Server Simplicity Vs
Network Complexity
Early server virtualization implementations
have demonstrated significant cost savings while greatly enhancing deployment
flexibility and adaptability. Next-generation server hardware will support
scores of VMs, and most software is designed with virtualization in
mind—meaning no enterprise application is off limits. This prospect has
significant network implications: It imposes unprecedented demands on bandwidth
and switching capacity, greatly increases topological complexity, and
complicates management and support by erasing the lines between physical and
virtual, network and server, and blurring the distinction between data and
storage networks.
When I think of the paradox of
server simplicity vs. network complexity,it is analogous to what would
happen if thousands of commuters gave up their individual cars for shared cabs,
with each passenger going to a different destination. While this would reduce
the number of vehicles on the road, it doesn’t reduce the number of trips—the
driver still must crisscross dropping off passengers at their offices. It also
greatly complicates the routing calculus. Instead of each commuter finding the
quickest path between home and office, the cab driver must optimize the pickup
and delivery schedule to minimize drive time and distance. Think of cab/cab
driver as a Top of Rack Switch in Data Center and Commuters as Servers.
(To be continued)
[Next post contains – Problems with
Increased Network Complexity]
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