Virtualization Technologies for Network Application Delivery Can Work

LAS VEGAS – Application Delivery Controllers (ADCs) are increasingly becoming available as virtualized appliances, but do they actually work? A panel of vendors debate the merits of virtualization technology for networking gear vs. having physical hardware.

It's a question tackled by a panel of vendors here at the Interop conference – including Certeon, Blue Coat, F5, Citrix and A10 – that debated the merits and limitations of virtual ADCs.

"I remember a day when the load balancers of yesteryear were all software based and it got to a point where you had to load balance the load balancers," Kenneth Salchow, senior technical marketing manager at F5 told the audience. "Cloud environments work on the basis that all compute resources are the same and that's just not true."

Salchow noted that for some things like SSL encryption it makes sense to have a hardware assist for performance. F5 this week made its own play for virtualized ADCs with the release of its BIG-IP virtual edition.

Shawn Cooney, co-founder of Certeon, noted that a software-only solution can work. Certeon only makes virtual ADCs at this point and it's a model that is working for them. Greg Smith, senior director of product marketing for NetScaler at Citrix, noted that his company has both virtual and physical appliances.

"We have users that rely on hardware for the front-end of the network for SSL, security and global load balancing and then rely on software-based virtual ADCs for applications," Smith said.

Smith added that by using a hybrid virtual and hardware approach to ADCs, it provides management flexibility and it has also increased Citrix's business by offering more choice to customers.

Paul Nicholson, director of product marketing at A10 Networks, commented that virtual ADCs make the most sense when performance isn't the most critical aspect. Nicholson said that virtual ADCs are easier to deploy than hardware, especially when an enterprise already has a virtual infrastructure.

Another key difference between the virtual networking gear and the physical hardware is cost.

"The virtual appliance is based on number of users and it's a value-based pricing model," Certeon's Cooney said. "You can use the cores you need and not just the cores that come in a box. Cores suck up a lot of energy."

Right now all the vendors on the panel support the VMware virtualization environment, though the consensus from the panel was that it's important to be virtualization hypervisor-agnostic. Even Citrix, which owns the Xen virtualization technology, is a backer of being hypervisor agnostic.

"It's important to be hypervisor-agnostic," Citrix's Smith said. "You should expect from your vendor that they will support multiple hypervisors and they shouldn't force you to migrate."

Smith added that when enterprises are looking at virtual ADCs they should also ensure that they're getting the same feature set and that they're getting the performance that they need.

Sean Michael Kerner is a senior editor at InternetNews.com, the news service of Internet.com, the network for technology professionals.

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This article was originally published on Apr 28, 2010
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