WAN optimisation has grown from a way to squeeze more out of corporate bandwidth to an enabler of datacentre consolidation and now is helping move those data centers into the cloud.
The technology continues its main function -- making response times faster over WAN links -- but now through software that runs on virtual machines it is becoming practical for use in public and private clouds where virtual environments rule. A few years ago, WAN optimization was locked within hardware appliances, but that is no longer the case.
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Virtualised versions of the old hardware appliances make it possible to deploy optimisation within public cloud provider networks, meaning cloud-based applications respond better. It also means data can be sent in less time to cloud storage facilities where it occupies less disk space (and so costs less) and is secure because it is encrypted.
The flexibility of application use that cloud environments can enable requires infrastructure that can optimise delivery of those applications. "The network infrastructure won't change as fast as the applications on them," which means WAN optimization itself needs to be as portable a possible, says Rob Shaughnessy, CTO at WAN optimization vendor Circadence.
This includes embedding WAN optimization in applications so optimization can be called upon as a service within the application. For example, the application running on a medical imaging device could include WAN optimisation support, making a separate WAN optimization appliance unnecessary at that end of a connection, Shaughnessy says.
Riverbed, too, is catering to the cloud, with its virtual versions that can run on virtual machines within cloud environments, says Mark Day, the company's chief scientist. It is also prepping a public cloud portal that tracks where customer assets are placed within the Amazon EC2 cloud so traffic bound for those assets can be optimized via a virtual instance of Riverbed's Steelhead appliance in the cloud.
Riverbed is has also announced a cloud storage product called Whitewater that deduplicates and encrypts data before it is sent to a public cloud storage service. The deduplication and encryption reduce the bytes sent over the WAN, improving time to send the data, and also reducing the amount of storage space customers need to buy from cloud storage providers.
A Riverbed customer, the International Justice Mission, uses its gear for WAN optimization, cloud optimization and storage optimization, saving money that it says translates directly into saving lives of sex trade victims, whom the agency advocates for (see "How WAN optimization is saving lives"). But the agency would still like to see better video optimization, according to the agency's vice president for information systems, John Lax. He realizes that may be asking too much given the nature of video, and that he may have to relent and buy more bandwidth.
Data center-to-data center and data center-to-cloud optimization are fast-growing areas, says Don MacVittie, technical marketing manager for F5, which has WAN optimization modules that plug into its Big-IP chassis. But software-only WAN optimization seems to be the trend.
Certeon CTO Donato Buccella says the company's focus on software running on commodity hardware sets its products up for deployment in the cloud, where traditional hardware appliances just don't fit. "There is no place to put those pizza boxes," he says. And in branches, putting software on server hardware with other applications simplifies deployments, he says. Multiple applications running on virtual machines in the same server can simplify branch-office infrastructure, he says. Virtual optimizers are more flexible than the hardware appliances that are limited by the memory and processing power of the hardware. Adjusting the resources allotted to the optimizing virtual machine can boost its capabilities, he says.
While most vendors agree that virtual versions of their products are important, the basic functions the products perform to optimize traffic are the vendors' bread and butter. Silver Peak's CTO and founder David Hughes divides WAN optimization techniques into three buckets: network memory, network acceleration and loss. Memory includes deduplication and compression of traffic, acceleration minimizes the effects of latency by keeping WAN pipes full, and loss deals with preventing retransmission of lost packets through forward error correction. Acceleration also includes application-specific optimization for chatty protocols such as CIFS, Hughes says. But application optimization isn't something Silver Peak focuses on.
Riverbed does, though, and boasts a long list of applications and protocols for which it has written specific optimization code. By understanding an application, the WAN optimization software can anticipate what it will call for next and prefetch, and can proxy responses locally to keep chatty back-and-forth off the WAN wire.
Even competitors who don't focus on application optimization acknowledge that it works, but point to possible challenges. Application optimization requires frequent updating as vendors issue new versions of their software. "It's extremely hard and extremely complex," Buccella says. "It's about staying on top of everything."
The downside is that applications must be optimized one at a time, and as new versions come out, that optimization has to be updated. "Trying to solve the problem one application at a time really doesn't scale," Hughes says. "It's not whether application-specific optimization works, it's whether you could ever keep up."
In addition to the focus on cloud, WAN optimization vendors are keen on optimizing traffic from mobile devices -- mainly laptops -- back to corporate sites and data centers that support WAN optimization controllers. Individual users can speed up interactions with applications and data without having to visit a corporate site.
Vendors are looking closely at extending this capability to tablets and smartphones, with Circadence last month introducing a client for Android devices. Other vendors have considered the possibility of such clients but have reservations.
Most agree that phones and tablets have the resources to support WAN optimization, but are less certain that businesses want it -- and if they do, what operating system they would want it for.
"The market feasibility needs to be resolved," Hughes says. "It's not clear there is a sufficient critical mass of critical applications on smartphones and tablets." If an optimization client were written for smartphones and tablets, it's unclear whether it would have all the features of an appliance or the current client for laptops, he says. "That's a good question that's yet to be resolved."
He suggests that WAN optimization for mobile phones and other handhelds be left to the makers of the devices. "In that ecosystem there's not a lot of room for extra innovation to be layered on top of them. It's not an attractive market."
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