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“You can’t manage what you can’t measure”

…so said a former colleague when I was working for a logistics company.

It’s a simple but effective mantra that has stuck with me ever since, as it applies to practically any project or process improvement. If you can’t establish a baseline, if you can’t quantify the here-and-now, how can you expect to demonstrate the effectiveness and benefit of change?

So it is with developing a WAN optimization strategy. Before you implement caching, deduplication or acceleration, it can only make sense to understand what’s happening on the network, by developing a baseline of line utilisation and the existing application mix. With this information, it is then possible to define an approach which attempts to align what the network delivers with what the business needs. WAN performance management is almost as much about controlling the applications you don’t want as it is about traffic acceleration – it’s easy to spend thousands of pounds on appliances which make unwanted traffic fly, whilst doing nothing for those business critical applications.

Controlling network traffic is nothing new. Early pioneers of the technology, such as Packeteer, recognised the value of visibility and control years ago, and their kind of products, along with (to some degree) network Quality of Service, facilitated early IP voice and video services through traffic prioritisation.

Then came the acceleration vendors. “With these boxes, whatever you have we’ll make it faster” they said. And in some extent they did. Caching and deduplication can allow massively more data to traverse the WAN. Unfortunately they offered little control over what was being prioritised, so some file transfers may have been improved, but so was the speed of all the unwanted traffic; the peer-to-peer, the personal hotmail access, the Tesco online shopping*, etc.

Exinda were the first mainstream vendor to appreciate that both the above approaches had merit, but that they should be complimentary, not existing in separate boxes with no co-operation (place all your traffic in a proprietary tunnel, then how can it be viewed or controlled?). They introduced the concept of Unified Performance Management and produced a single appliance that has the visibility and control of a packet shaping device, with the performance benefits of an acceleration controller. And we’re not just talking about “this is web traffic, this is a Citrix app”, Exinda’s layer 7 visibility shows exactly what web traffic, which Citrix application: proper deep application inspection. Coupled with comprehensive real-time and historical reporting, that provides the baseline, the measurement.

That layer 7 technology then facilitates control at the same level of granularity. Some web sites may be business critical, others purely recreational. With layer 7 control, individual URLs can be classified and prioritised separately, while voice calls are guaranteed network access and software updates can be forced to load in the background when no other applications are demanding network access. That’s the management.

The next piece is the acceleration itself. Technologies such as caching and deduplication (wan memory in Exinda-speak), manipulation of the actual tcp, spoofing acknowledgements, aggregating small packets into larger segments, all contribute towards getting more data through the same line, more efficiently. Allied with the advanced visibility and control functionality, it’s possible to ensure that only key applications get the acceleration benefit.

Times change, the industry matures, and other vendors are moving towards their own UPM solutions. Exinda’s head start, however, means that they’re already looking at how next to deliver an improved user experience, with object caching for videos, voice call quality assessment, and integration with enterprise management and reporting services. Their same core principles remain, however: you have to see and understand traffic it before you can optimise it. You can’t manage what you can’t measure.

*Other supermarkets exist.

EDN has been working with Exinda for over five years. We have extensive experience of delivering the benefits of Exinda-based WAN optimisation to organistions of all sizes, from single unit traffic shaping deployments, to corporate global networks. We have delivered solutions over leased lines, internet VPNs, satellites and global MPLS covering Europe, Australasia, Asia and the US. If you want to find out how we and Exinda can help you develop your own WAN optimisation strategy, please get in touch.

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