SD-WAN: A cure for finger-pointing?

With the rise of SD-WAN, Citrix believes it's well placed to capture a significant share of the market.

Chalan Aras, Citrix

SD-WAN is a crowded field, and it’s projected the market is going to double in the next five years, reaching an estimated $6-billion by the end of the decade. In just a few years, perhaps as many as half of all businesses are going to be using SD-WAN, according to analysts.

Like any busy marketplace, the buyer is offered a choice between older and established vendors, or younger and more agile players. One can also expect some consolidation, such as the recent acquisition of Viptella by Cisco.

Why is SD-WAN so important? In short, it increases bandwidth and provides increased visibility and optimises traffic between branch locations and the datacentre.

Dr Chalan Aras, vice-president of the Citrix Netscaler and SD-WAN business, told the Margin while the company had long had a WAN optimisation product, it had become apparent that application patterns were gradually changing. Applications were no longer just being delivered from a company’s datacentre, and there was gradual move towards cloud.

Apps were also becoming more interactive, and needed to be delivered in real time.

Aras says Citrix decided to consolidate all its SD-WAN products under the Netscaler brand.

Now that all application traffic is carried using Netscaler technology, visibility has become increasingly available.

He says it has introduced a very deep and broad application classification toolkit and detects applications using a wide array of technologies, such as the IP address, DNS, and the cadence of packets, to name a few.

This information shows the top applications per branch and network, which can be used to make policy decisions.

While an application can simply be blocked, Citrix is unique in the market in that it can block sub-applications, according to Aras. An example of this would be granting access to SharePoint for certain employees, or blocking the video functions of Facebook.

With regards to getting visibility on an end user’s device, he says Citrix has shied away from installing an agent on the device.

“It’s a little creepy and people don’t like it, unless it’s a corporate mandated component,” he says.

A better way, according to Aras, is to proxy the user’s experience of an application, without invading their privacy.  


He says real time interactive applications were the toughest for a network to deal with because they don’t tolerate any gaps in connectivity. Here, again, visibility into the network is key.

These gaps in performance, or ‘brownouts’, were quite common, says Aras, relating a story of a Citrix customer running a large soft drink bottling plant. “They’re using our SD-WAN product and they call and tell us we’ve got a bug in our product.”

Aras says they had detected packet drops on the network, but the network provider had denied there were any problems.

This came down to: “Do I trust the network provider, or do I trust you?” he says, adding that Citrix had been ‘presumed guilty’.

After a few weeks of finger-pointing, the network provider had eventually accepted the blame for the loss of performance, as it had been busy with core routing changes.

Aras says in the past, a user could complain if performance dropped off, but there was little recourse.

Citrix, however, does end-to-end measurement, ‘and everything in between, so we can tell if there’s a little blip’.

Aras says many customers are still figuring out which SD-WAN offering to buy.

“Companies are now asking whom do they choose for SD-WAN. A year ago, it was more of ‘why do I need SD-WAN?’

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