LONDON, December 2, 2010 - The proliferation of cloud computing is increasing the dependence of both consumers and businesses on broadband access.
Use of cloud computing by businesses as a whole is growing at 80 percent in the developed world, according to analyst group Forrester – albeit from a small base – and this in turn is diverting critical business traffic from LAN connections or dedicated circuits to DSL or fiber-based broadband access links to the internet.
This in turn raises the related issues of cost and performance, particularly where cloud services are replacing local connections with longer distance end-to-end links, in some cases between points in different countries. This can defeat the object of cloud computing, which is to reduce costs through economies of scale achieved by sharing infrastructure as well as software over the internet, and to provide a better experience to users or customers through familiar web-based interfaces. If poor network connections mean application response times increase, that experience gets worse.
The objective is to achieve adequate performance at acceptable cost, making the best use of given bandwidth through a combination of WAN (Wide Area Networking) optimization and caching within the network, according to James Staten, vice president and principal analyst at Forrester, and co-author of several reports about cloud performance issues. “The biggest issues are cost,” said Staten. “More bandwidth costs more, WAN optimization costs more, caching costs more, and so on. Each business has to determine what customer experience they demand and how much they are willing to throw at the problem.”
Staten recommends extensive use of cache in most cases to resolve performance issues, since bandwidth alone does little to help when the issue is delay caused simply by the distances the signals need to travel. The impact of distance is amplified further when there is repeated two-way chatter between applications involving transmission of small messages. In such cases, the principle remedy is to distribute key parts of applications and data to caches close to the users to reduce the distances involved and bring latency down to acceptable levels.
Then WAN optimisation can also help by reducing the chatter between applications, and batching messages together so that they are sent as one large file rather than numerous smaller chunks each requiring acknowledgement and bumping up latency.
But before deploying cache or WAN optimization tools, Staten urges enterprises to simulate and test their deployment first to ensure that performance will be good enough without spending more than necessary. “You must test. Use services like Keynote, CompuWare Gomez or others to determine what the customer experience is like right now and simulate what it would be like as a remote service,“ said Staten, referring to several well known platforms for assessing performance of web based applications. “Test the options you are considering, such as cloud or traditional hosting. But be sure to optimize the application, the route, and cache everywhere.”
The importance of realistic testing is also emphasized by Nigel Hawthorn, vice president of marketing at WAN optimization tools vendor Blue Coat. “IT departments should test response times for specific application actions before a cloud service is implemented and then test before migrating. The important piece of the testing is to ensure that tests are carried out from users placed in all offices as performance can differ worldwide based on factors such as where the cloud service is based and network connections.”
But if this testing is done properly, Hawthorn argued enterprises may actually reduce their networking costs in cases where expensive leased circuits are replaced by competitive DSL access services.