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It's Not About WAN Optimization Techniques
[September 08, 2006]

It's Not About WAN Optimization Techniques

TMCnet WAN Optimization Columnist
WAN performance has become crucial for overall application performance because an increasing number of enterprise employees receive their critical applications through WANs. This is driven by the fact that most employees are located in branches (40 percent to 60 percent depending on the industry and size of the company) and companies are reducing the numbers of local servers for security and cost reasons.

However maximizing application performance over the WAN is a challenging task because:
  • Applications have typically been natively designed to run on LANs, not WANs. Thus, application chattiness or the excessive use of bandwidth inducing latency and packet loss can become prevalent on a WAN.
  • Non-critical TCP/IP traffic continues to grow rapidly — on average 25% a year — affecting the performance of critical applications.
  • Different applications with diverging network behaviors and requirements compete for bandwidth. Real-time applications such as VoIP do not have the same profile as, for instance, file transfers.
  • WANs are “living” infrastructures subject to periodic changes such as the deployment of new applications, the addition of new sites, new users, etc. that render any optimization exercise difficult.
  • Isolating network application performance incidence is extremely difficult. It tends to be intermittent and difficult to reproduce.
  • Adding more bandwidth to improve application performance doesn’t always solve the problem and is economically untenable. More bandwidth, for instance, doesn’t address the problem of delays due to distance or micro-congestions because of sudden surges of simultaneous users.

To be able to tackle the challenge of WAN optimization and satisfy their end-users, network managers need to have the right objective in mind and look for the right features in an optimization tool.
Marketing hype originating from the WAN optimization industry tends to advocate for “application acceleration.” Often what is offered then is a suite of technologies that “accelerate” all applications in an indiscriminate fashion. While these technologies can be efficient and accelerating all applications can be an appealing value proposition, it is really a trap. Indeed, improving the performance of all applications leads to end-users using ever more recreational applications, which in turn tends to grow faster than critical applications traffic impacting the performance of critical applications. This leads to a need for more bandwidth or more optimization tools.  It is the start of a vicious cycle.
Instead, I urge network managers to consider what their end-users are really looking for. Namely, guaranteeing the performance of critical applications under all circumstances as opposed to accelerating all applications in an indiscriminate fashion. After all, no network manager will lose sleep over the fact that downloading the latest Madonna clip is slow; however, he might if the performance of the end-of-the-month SAP (News - Alert) data consolidation doesn’t perform to the CFO’s liking.
Once the right goal has been established, network managers need to shop around for WAN optimization tools with the right features. Here again, they can be overwhelmed by technical and marketing buzzwords describing yet another way of optimizing or accelerating application performance over the WAN. Claims and counter claims can be confusing. Interestingly enough most of this debate is centered on very minute optimization techniques (e.g., TCP acceleration, CIFS optimization, compression, etc.) and glosses over much more essential features that a WAN optimization tool should offer.
It is important to understand the basic function of each optimization technique, as each is better suited for a certain type of traffic. For instance, bandwidth-hungry applications respond well to compression while transactional applications are sensitive to delay and need TCP acceleration. However, it is fair to assume that most WAN optimization solutions today offer a fair combination of all required technologies. What is less talked about and essential are the “other features” that make a WAN optimization tool a real business tool rather than just another “technological gizmo.” 
I believe that an efficient WAN optimization solution should offer the following features:
  • Optimize according to business criticality because all applications are not equally important for an organization. This goes back to the goal of guaranteeing the performance of critical applications rather than accelerating all applications.
  • Be application objective-driven instead of network policy-driven, because network policy-driven solutions cannot cope with all the changes a WAN is subject to and because end-users expectations are expressed in terms of application performance objectives, not network policies.
  • Provide exhaustive monitoring tools, because proactive trouble-shooting and reporting is key to end-users’ quality of experience.
  • Optimize the WAN globally rather than a link at a time, because it is the only way to optimize meshed flows such as VoIP.
  • Seamlessly combine multiples optimization technologies, because applications (real-time vs. file transfer) behave differently and respond better to different optimization technologies.
  • Be simultaneously symmetrical and asymmetrical because the WAN is made of different types of sites with different levels of importance and traffic complexity.
For all of these reasons, network managers should shy away from endless discussions about optimization techniques and instead concentrate on the “business” features of WAN optimization solutions if they are to improve their end-users quality of experience.
Vargha Moayed is executive vice president of Ipanema Technologies, a leading provider of application traffic management systems for wide area networks.

For more on WAN Optimization and other related technologies,  check out the conference program at the upcoming Internet Telephony Conference & EXPO in San Diego, CA (News - Alert), October 10-13.

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