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Saturday, January 7, 2012

Network Virtualization - Old Hat Or New Hope?

Network virtualization, which Cisco Systems describes as “efficient utilization of network resources through logical segmentation of a single physical network” is a concept that’s at once old and new. VPNs (virtual private networks), common now in many firms, are early examples of virtualized networks.

Yet, in late 2010, Toby Owen, product manager for cloud and managed solutions provider Rackspace (, predicted network virtualization would be an important development for 2011, with companies performing upgrades “setting us up for faster progress in the years beyond.” So, how can a mature solution be new? As with many computing topics, the answer lies in technology developments that are both convoluted and straightforward

Cisco’s technical definition can be explained more simply as dividing the traffic pipeline of a traditional, hardware- based network into multiple, individual tunnels—smaller networks that service a specific population or enable a dedicated task. In much thesame way that multiple phone conversations can run over the same line without the users experiencing crosstalk, virtual networks can co-exist as individual tunnels (small or large) without interfering with one another

As we mentioned earlier, a VPN is an example of a virtualized network— it’s an isolated, secure data tunnel that exists, not as a physical resource, but rather as one created and managed by software. As Neil Matchan, director of IT Services for IT solutions provider InterDev (, points out, “Even a DMZ [demilitarized zone] and a firewall are effectively network virtualization. You are still making a separate network within another network.” (A DMZ is a specialized port that provides unrestricted access to certain corporate resources for a specific purpose, such as serving content to the Web.)

However, while VPNs and DMZs fit the broad description of network virtualization, they are a long way from the solutions envisioned for this technology’s future

Matchan describes a number of scenarios where network virtualization could be a real boon for SMBs. Perhaps foremost are with companies that face strict regulatory requirements, such as those in the financial and healthcare sectors. Segmentation of specific resources via a dedicated virtual network is easier to secure and shut down than restricted access to a general network.

In the current economy, he says network virtualization could also serve well for companies engaged in mergers or that need to combine resources with those of another company to qualify for a contract bid. “We are helping a company through a merger right now,” Matchan says. “Each company needs to maintain its own IP address, so how can we bring these two companies together so they can talk? Network virtualization allows us to segment two halves of one umbrella company.”

“You could even create a virtual network within one server box,” he continues. “Let’s say transactions between the two servers need to happen at very high speeds, and putting them onto the general network slows things down. You create a virtual switch shared between the servers. They are the only things talking to each other and it creates a much faster network. Such a solution would facilitate exchange of large quantities of data, such as medical imaging or insurance histories.”

Another example Matchan offers is software or video development firms where five employees need 10Gb (gigabit) network speeds, but it’s not feasible to purchase five 10Gb switches at $10,000 apiece. With a virtual network, he says, “you wouldn’t need individual switches. Also, you could make the developers high priority. They get full resource and the rest goes to your employees. On days when they’re not using it all, the extra bandwidth is shared with the rest of the office.”

Doctors’ offices that need to hook into a hospital’s network; architectural firms wanting to let subs use their large format printer but nothing else (a virtual network can provide access as limited as a single printer); the list of possibilities goes on and on. Best of all, says Matchan, when properly orchestrated, virtualized networks can be easier to manage and secure.

In the example of the shared printer, he says, “Rather than give vendors usernames and passwords on my network, I only have to worry about the tunnel to the printer. When the project is over, I don’t have to reset 15 passwords. I just shut the tunnel down. And, because they never had access to the network, they could not have compromised it.”

With all these benefits, why hasn’t network virtualization gotten more attention before now? On a large scale, it has. In the past few years, entities from the Zurich airport to Resorts World at Sentosa (a megacomplex in Singapore with six hotels, a casino, and four theme parks) have used network virtualization to increase network flexibility while reducing energy consumption.

Furthermore, it’s a core component of cloud computing, so anyone having data or applications hosted in the cloud is already running on a virtual network. According to Steven Walters, manager of solutions architects for cloud services provider NSPI (, “Network virtualization is the abilityto create a true multi-tenantinfrastructure. The network traffic is isolated and controlled so no customer impacts any other.

Walters points out that the technologies developed to securely segregate multiple customers’ data and application delivery can be used to service individual customers, as well. He also notes that economies of scale have made it affordable for smaller firms to leverage the power of network virtualization already built into cloud solutions

“You cannot deploy and manage these systems and use them at 10 to 15% utilization and have any sort of cost-benefit ratio,” he says. “It’s like virtualized servers—it becomes cost effective when you get to 70 to 80% utilization of those resources.”

If cloud computing brought network virtualization to small businesses, another evolving solution may end up making the technology virtually ubiquitous (no pun intended). The current Internet protocol, IPv4 (Internet Protocol Version 4), is slowly being replaced with a newer protocol, IPv6.

IPv6 offers some major benefits over IPv4, including more robust security. However, more important for network virtualization is the way IPv6 works with network addresses. (Just as a house requires a street address, every point of access on a network, whether virtual or physical, requires its own network address, such as These strings of
numbers underlie the domain names we recognize as website URLs.)

First of all, IPv6 will make it possible for enormous virtual networks to be created and then dissolved at will, because it uses an addressing scheme that can support far more addresses than IPv4. Whereas IPv4 supports approximately four billion addresses, experts peg the number of addresses that IPv6 can support at 3.4×1038, give or take a few trillion. As Dave Evans, chief futurist for Cisco, has stated, that’s close to 50 thousand trillion trillion addresses for every person on the planet.

With IPv6 as the standard, we should never run out of IP addresses—at least not in the foreseeable future—and companies can use as many as they need for their virtual networks. With IPv4 as the standard, the eventuality of an address shortage made such cavalier use of them impractical and expensive.

In early 2011, that eventuality became reality when the Internet Assigned Numbers
Authority, which allocates IP addresses in bulk, ran out. Within a few years—certainly less than a decade— the entities who hold the remaining allocations will run out, too. So now, the race to IPv6 is on.

IPv6 is already supported by later versions of Windows, but there are a lot of older routers, websites, and other Internet-connected elements—especially in the United States—that need updating or replacing. Needless to say, it’s going to be a very interesting decade for some folks.

For those who jump on board, IPv6 offers other major benefits relating to network addresses (and network virtualization), including the ability for self-configuration. As Owen noted in his report, network virtualization soon will allow “ondemand configuration of network conversations, as needed, to be isolated and private, solely accessible to sender and receiver, and then be dynamically reconfigured for the next conversation.”

Walters concurs. “The industry is moving towards self-provisioning portals. If you want to turn on a new SharePoint server, you could go to a self-provisioning tool, choose a server template, and then publish to the Internet. You could have a threemonth project where you are using vendors you might never work with again. You could literally turn the portal on and off as needed.”

And, while these capabilities that are automatically and dynamically configured through IPv6 may not be widely realistic for SMBs yet, firms can easily enjoy similar network virtualization benefits, working with cloud providers or on-premise IT support.

“In a multi-tenant, segmented solution, we can create an extranet on the fly,” Walters says. (An extranet is a network that allows controlled access to company network resources by outside parties, such as vendors or clients.) “It can be completely isolated in the network layer from the customer’s internal system. When those new resources are turned on, they inherit the security and network characteristics already in place, so those
systems can live anywhere in that cloud infrastructure.”

In other words, the full potential of network virtualization is still a ways off (and depends upon how fast people hop aboard the IPv6 train), but even the smallest business can leverage its potential now through the cloud or with limited on-premise deployments. It’s pretty exciting stuff. ●

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