Wide area acceleration
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Wide area networks are being clogged with data traffic. But a new wave of tools...
There are many reasons for organisations embarking on IT consolidation. Some need to bring control to a sprawling IT infrastructure that has grown through serial M&A activity; others see the centralisation of IT as a means of reducing support costs and improving security; for others it is the path to increased business agility through the ability to introduce change centrally.
But efforts to suck servers and storage devices out of branch offices have been paralleled by the drive to deliver business applications over the Internet from central sites rather than have the software running locally. The upshot has been an explosion in the amount of data traffic behind pumped over the organisation's wide area network (WAN). And the problem is that without careful management of those new demands for bandwidth, the consequences for both the user and the organisation can be dire.
Adam Davison, European VP of sales at WAN optimisation specialist Expand Networks, describes how one retailer he worked with simply went from using 'green screen' sales terminals to graphical user interfaces. But the increase in bandwidth consumed in feeding the new terminal resulted in the retailer's customers having to wait up to 10 seconds just to have their receipt printed. Frustrations such as these can have a damaging impact on repeat business, he says.
More typically, users simply want to access and send more data, more frequently over the WAN - whether that is a hospital transmitting patient records data, a manufacturer working through its ERP system with its fabrication plants in the Far East or a film studio sending daily 'rushes' to production facilities for review.
Over the past two years, several key technologies have emerged that promise to address such demands. But in spite of a variety of approaches, says Davison, they are all aiming to tackle the same problem: "To give the user an acceptable performance when putting applications on a WAN."
That may sound simple in principle, but those optimisation and acceleration efforts are a host of sophisticated technologies. Not all vendors - or, indeed, analysts - agree on the blend of technologies that should be brought to bear on the optimisation of application performance and file transfer over a WAN, but the list they are picking from includes traffic prioritisation, protocol acceleration, IP optimisation, compression and application optimisation.
That is because the performance of an application over a WAN can be impacted by many different factors - ranging from the suitability of the application code for running over a WAN to load balancing within the data centre. But they all aim to address the core issues of latency, congestion and quality of service that are fundamentally aimed at improving performance on the network.
One of the problems faced by businesses intent on centralising file servers is that the sharing of files becomes especially tricky when Windows is involved. The Common Internet File Sharing (CIFS) protocol used by Windows works well with local servers, but it is a very 'chatty' way to access files, says Ian Kennedy, head of technical operations at networking systems giant Cisco Systems in the UK and Ireland.
Each time a user wants to open a Windows file, multiple messages flit across the network: for a Word document roughly 1MB in size, as many as 1,500 messages might be swapped in opening the file. "You put that on a remote end, and you can be looking at a 90 second delay," says Kennedy.
This problem of dealing with file sharing is exacerbated when businesses introduce satellite links, commonly found in organisations with a large number of disparate branch offices, where bandwidth is at a premium. "Nearly all of our large customers have some component of satellite, which means the challenges of latency will be around for some time," says Steven Wastie, VP for emerging technologies at Juniper Networks, which sells WAN application acceleration systems.
One approach to improving application performance is to use wide area file sharing (WAFS) technologies. Typically these are based on caching technologies which can reduce the volume of traffic passing over the network. The use of protocol optimising technology can ensure that CIFS is made more effective.
But even when WAFS can help reduce the problem of latency - some vendors claim to offer up to a 20-fold increase in available bandwidth - the performance of applications is still unlikely to match that delivered locally. There are two remaining challenges to delivering applications over WANs: network congestion and quality of service.
WAFS technology is fine for a limited number of primarily Windows-based applications, but it does little to address the problem of the increasing number of business applications that are being run over the Internet. "The 'webification' of applications has a significant impact on bandwidth availability. Application developers seem to be out of touch with what is happening on the network, and many of them are deploying applications without knowing how it will perform on the network," says Davison.
Through traffic compression, organisations can cut down on the amount of data that they send over the network. Typically, traffic can be reduced by 70% to 80% by ensuring that only changes to data are being sent, says Juniper's Wastie. This has important ramifications for backing up over a WAN. "Some customers have found that moving traffic onto the WAN can mean back-up takes longer than the overnight window that is available. That's a big problem," he adds.
At this stage organisations have probably achieved the "M25 model" of WAN optimisation, says Roger Hockaday, European marketing director of Packeteer, a vendor of products that monitor, control and accelerate application performance over WANs and the Internet. "You need to get things running smoother, but the only option appears to be adding more lanes. What you actually need is to understand the traffic, where it's going."
Through analysing network traffic CIOs can work out what applications are taking up most bandwidth and whether these are business-critical. For example, cricket fans streaming live audio at work of England's victory in the Ashes could have been eating up vital bandwidth. "Once you know that you're only seeing the traffic that is absolutely necessary, you can then enforce quality of service metrics to ensure that the most important applications are best served," says Hockaday.
Back in 2003, Packeteer observed how Internet service providers were starting to use multiprotocol label switching (MPLS) - an initiative from the Internet Engineering Task Force standards body for ensuring that certain packets are prioritised - for implementing quality of service. "Now enterprise demand for MPLS outstrips that of service providers," says Hockaday.
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Market compression
Given the unstoppable growth in the volumes of data being sent over wide area networks, demand for WAN optimisation - in all its various guises - is soaring (see graph). And while those volumes are being driven by server consolidation and application 'webification', other fundamental changes to the communications infrastructure are going to further clog up the pipe, not least of all Internet telephony.
Although the increasingly widespread adoption of voice over Internet Protocol will inevitably increase the data volumes travelling across the WAN, this is not being regarded as a bandwidth issue. For any business running voice traffic over its WAN, latency and quality of service are paramount as telephone conversations are particularly dependent on minimal latency.
The potential demand for products that manage and speed data movement over the WAN has not been lost on the large network equipment makers who have rushed to snap up WAN specialists over the past year.
Packeteer paid $20 million for Mentat and its technology for accelerating applications over satellite and long-haul networks; Juniper paid $337 million for Peribit Networks, a pioneer of WAN optimisation; in May, Cisco acquired application optimisation vendor FineGround Networks for $70 million to sit alongside its earlier $82 million buy-out of WAFS company Actona Technologies; and, latterly, application traffic management product maker F5 Networks agreed to buy WAN application accelerator Swan Labs for $43 million.
And there are plenty of other start-ups waiting in the wings with hot WAN products, including Orbital Data, Riverbed Technology, Radware, Ipanema Technologies, Silver Peak and Streamcore. With customers keen to have application acceleration built directly into their WAN switches, says Thomas Mendel of analyst group Forrester Research, such companies are likely to end up as part of a wider offering - a message that the likes of Cisco and Juniper are keen to push.
"Ultimately it makes most sense to embed as much intelligence as you can in the network," says Cisco's Kennedy. "It makes life easier for everyone."
