The growing trend toward globalization means enterprises are deploying more employees in remote branch offices, and these employees may often need to collaborate with one another. At the same time, enterprises are centralizing their business-critical applications and hosting dynamic content. Security and compliance concerns are also creating increased pressure to remove data from branch offices.

As a result, the productivity of branch office employees who use centralized applications suffers because the corporate WAN is not optimized for a large number of users or large data transfers. Users may find that application performance is poor or have difficulty accessing corporate data due to the high latency of applications flowing over the WAN. Latency issues can cripple applications and the business transactions that depend on them. Using a Web application to download large content files is often so slow that the applications are useless in remote offices and for mobile workers.

Faced with poor performance that affects the bottom line and the need for business continuity, organizations once had only one option: buying more bandwidth, which does not really solve the underlying latency problem. Today, however, another option is available: WAN acceleration.

New WAN acceleration technologies have emerged that deliver performance improvements across a large number of applications. These solutions enable a network to support higher throughput and thus speed up applications, and they also support more applications to more offices over the existing WAN infrastructure.

Global enterprises that do not have an acceleration solution in place are, in essence, paying their employees to spend idle time waiting for file transfers to complete. An acceleration solution will improve the user experience and boost productivity for all users.

AN UNDERESTIMATED CHALLENGE

The need to enable effective real-time collaboration over the WAN has generated technologies and devices designed specifically to improve WAN application performance. Enterprises have begun implementing these devices but have underestimated the challenge of installing and managing them at every remote branch location. These boxes can be difficult and time-consuming to manage on a global scale, particularly for enterprises with limited IT resources.

To address the challenges of implementing WAN acceleration, some enterprises are choosing to outsource WAN acceleration to a managed service provider. These services enable organizations to improve application performance over the WAN, maximize existing resources, improve bandwidth performance and maximize productivity on a global scale, without having to add and manage new infrastructure on their own.

Enterprises interested in outsourcing should understand there is not a one-size-fits-all solution to this issue, as every network is different. Organizations should seek solution providers that are not only able to provide an accurate measurement and evaluation of WAN application performance but also practice due diligence and follow best practices.

Having a central point of contact at the service provider is key to a successful WAN-acceleration solution. This is particularly true for large networks where remote offices do not have servers, and there is limited IT staff onsite to handle daily tasks. A provider can help ease the burden of managing a large WAN-acceleration deployment by handling remote provisioning, management and post-installation performance monitoring. The ability to centrally generate network traffic reports is also important for scalability.

A provider with extensive experience in evaluating global networking solutions should have expertise in all of the available technology options and be able to select and customize the most appropriate devices for a particular environment. Regardless of which device manufacturers are chosen, one of the best reasons to outsource is to ensure getting the right equipment to augment or build a WAN-acceleration solution.

Solution providers should be able to provide an accurate measurement and evaluation of WAN application performance.

Enterprises should look for solutions providers that are vendor agnostic and have worked with global customers with varied types and sizes of networks. A service provider should also be able to fine-tune the overall configuration between locations to maximize network performance—and know when to purchase more bandwidth to improve performance.

The most scalable WAN-acceleration solutions are transparent to an enterprise's existing infrastructure.

Outsourcing a managed WAN-acceleration solution as a means of delivering LAN-like application performance over low-cost, low-bandwidth connections can provide a number of benefits. Companies can maximize the use of their existing bandwidth resources, avoid adding infrastructure, improve application performance, and improve network efficiency and security through data/storage consolidation. They can lower costs by recouping server capacity and network bandwidth, improve application availability and scalability in support of business continuity plans, and improve satisfaction for remote users.

These solutions can reduce the impact of latency on global and remote locations by shortening transmission times for sending large files to remote sites. Lower latency and faster file transfers translate into improved employee productivity and also free up the WAN for other tasks.

Bill Dodds is vice president of sales and marketing for Virtela Communications, Greenwood Village, Colo.

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WAN acceleration choices

by Daniel Schrader

The first lesson of application acceleration is that bandwidth is not the answer. Bigger pipes or wider information highways will not change packet speed. Generally, response time is not a factor of the size of the wire, but of the delays caused by devices that connect those wires together'the switches, routers and security products that add milliseconds to the simplest network request. Part of the problem is that modern packet networks employ not-so-modern protocols designed for simple applications running across a local area network.

The time to deliver a message is calculated as the number of packets required to deliver the message, multiplied by the network latency. This simplistic view of the process, however, does not take into account any computer processing time, packet loss or transport protocol acknowledgements time.

Application performance can be improved, however, through the use of technologies that reduce the number of packets to be delivered, move content closer to the end-user and improve server response times by off-loading CPU-intensive tasks such as compression and encryption.

Traditionally, network optimization encompassed two models, symmetric and asymmetric. Symmetric acceleration (or sometimes called WAN acceleration) is used for data center-to-data center or data center-to-branch office communication. The symmetrical approach puts an acceleration device at each end of a connection to accelerate everything going across the wire.

By working at a low level in the network stack, symmetrical acceleration can support a wide range of applications. Because the pairs of symmetrical devices are designed to work with each other, high rates of compression, intelligent caching and protocol optimization can be used. Symmetrical approaches, however, have drawbacks, including the cost of installing devices in every branch, management overhead and that they typically do not improve performance for road warriors, partners or customers.

Asymmetric accelerators (often called application accelerators) can improve application performance for anyone accessing applications across the Internet. These accelerators typically take advantage of the decompression and caching capabilities of a client's browsers to reduce the amount of network traffic and improve application performance.

Because application accelerators are only installed in the data center, cost of deployment is low. Since there is no client or branch office component, however, application accelerators trail their symmetrical cousins in performance and protocol support.

Recently, a number of vendors have offered hybrid approaches, where a data center appliance can work asymmetrically or function as part of a network of acceleration devices. In some cases, vendors have begun to offer client software or sometimes client applets that install when a customer, road warrior or partner first views an application's Web site. The hybrid approach offers flexibility to network architects but can add both complexity and management overhead.

When looking at application-acceleration devices, customers should do more than just look at a feature checklist. They also should consider ease of deployment and ease of management, and the availability of profiles tuned for their enterprise application.

Both WAN and application-accelerator technology can pay for themselves through improved productivity and customer satisfaction, and through savings of operating and capital expenditures. As important as the quantifiable savings are, the intangible benefits are Web applications that run faster, respond more quickly and offer a better experience.

Daniel Schrader is a security and application intelligence product marketer for Nortel, Toronto.

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