Bandwidth limitations and latency have become a common way of life for WAN managers who can’t afford an upgrade, but virtualization and data centre consolidation are forcing many IT shops to confront these problems headlong. Such was the case for a London-based law firm that found WAN optimisation to be a viable answer.
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For the London-based global law firm, solving WAN bandwidth limitations and latency problems was vital to enabling data centre consolidation. The IT department had virtualized 6,000 desktops, and then wanted to consolidate its four data centres.
The law firm’s users work on virtual desktops delivered via Citrix to thin clients. Nothing is stored locally; all data and applications are streamed down from a data centre. But users were experiencing inconsistent network performance from one location to another and even throughout the day. “It wasn’t a case of trying to get faster downloads,” said Warren Lynn, the law firm’s network engineer. “It was a problem with keyboard strokes and screen updates. Letters on the screen appeared a few seconds after you pressed a key. It was like looking at the Internet in the early ‘90s when the screen slowly rendered a JPEG.” The law firm had a packet shaper in place that was purely a quality of service device. It couldn’t cache the network and had limited acceleration capabilities. “It just didn’t seem to work very well. All it did was say, ‘this traffic is more important than that traffic,’” Lynn said.
After talking to several WAN optimisation vendors in the space, the firm decided to go with Silver Peak’s NX series of appliances for its network integrity features. The appliances optimize the network for quality by removing packets that are locked or out of order. The firm deployed 30 appliances in each of its two mesh networks as well as a number of point-to-point links for a total of 70 appliances.
With the WAN optimisation appliances in place, the law firm was able to move forward with its data centre consolidation project. “Instead of having four children to feed, we currently have three. At a minimum we want two -- for disaster recovery purposes -- and we’re currently in the process of creating a proof of concept for removing our other regional data centre in Hong Kong,” Lynn said.
In addition to the cost savings resulting from shutting down an entire data centre, the law firm now saves on WAN circuits. Prior to installing the WAN optimisation appliances, bandwidth was growing at a rate of about 10% a year, Lynn said. The IT department was performing WAN circuit upgrades for at least one office about once a month. Since the Silver Peak installation nearly two years ago, only one office has needed an upgrade. “At the very least, just in WAN circuits, we’ve saved more than two million pounds,” Lynn said.
Optimising the network has also enabled the law firm to deliver video through Citrix -- something the IT department struggled with previously. “We thought we’d have to stop using Citrix and move back to managing 6,000 servers. But a combination of network memory, caching and enhancements within Citrix itself in terms of how video is handled, have allowed us to avoid doing that,” Lynn said.
Now, live video is set up in London and streamed to all the offices. Partners conduct meetings via video and create video of company updates instead of email newsletters. The video also allows IT to deliver training to the desktop. Users can access a database of training videos on a range of topics, from using information systems to law, without leaving the office.
Another unexpected benefit of using a WAN optimisation appliance is the added visibility into the network. Any of the 30 sites in the network can talk to another site directly. These connections were impossible to monitor prior to the Silver Peak implementation, Lynn said. “Silver Peak is the only thing we use to monitor the entire network. It sees every packet that leaves any location and any packet that arrives at a location, and it can tell you how long it took to get there,” Lynn said.
-- Crystal Bedell is an award-winning writer and editor specialising in technology. She can be reached at firstname.lastname@example.org.