The pitfalls of stand-alone WAN Optimisation
There are often many misconceptions around the definition of WAN optimisation, especially when it is considered as a ‘stand-alone’ concept in the context of trying to make applications faster.
That is because ‘optimizing the WAN’ implies you are making the WAN faster. The problem is that a WAN is either a dedicated link between two locations (old school) or a connection to a remote site across the Internet (new school). In the case of the former, there really isn’t a whole lot you can do to that network to make it faster. In the case of the latter, there really isn't anything you can do to influence the networking components out there, on the internet – or ‘in the cloud’ – to make it faster.
In the data centre, optimizing the network has real meaning. It is about modifying routing and switching, moving segments and changing VLANs. It is also about fatter connections and changing the way in which network traffic flows.
But when it comes to the WAN, you have very little you need to tweak.
This is the reason when people used the term WAN Optimisation, what they really meant was ‘we squish data down so there are fewer packets and thus, it traverses the network faster’.
APPLICATIONS are not NETWORKS
What IT and business stakeholders really want – what they care about and what they are basing key performance indicators on – is faster applications. And if you focus on optimizing the network, well, that is not really the right approach. The right approach is to focus on application delivery.
Before we go any further, it is important to consider what ‘application delivery’ really means. Like most technology jargon, there are certain terms and phrases that end up mangled, conflated and generally misapplied as they gain traction in the wider market. Cloud is merely the latest incarnation of this phenomenon, and there will be others in the future. Guaranteed.
Of late, the term ‘application delivery’ has been creeping up into the vernacular. That could be because cloud has pushed it to the fore, necessarily. Cloud purports to eliminate the ‘concern’ of infrastructure and allows IT to focus on… you guessed it, the application. Which in turn means the delivery of applications is becoming more and more pervasive in the strategic vocabulary of the market.
Application delivery is important for a number of reasons, in particular because of its unique transport and application layer behaviours and what those imply in terms of performance. Then you focus on resolving any issues that arise because of that behaviour. Then, if you still need to, you can apply traditional techniques like compression and de-duplication and reduce the size to make the results of your initial efforts even better.
But if you aren't focusing on those initial efforts, simply put, you are doing it wrong. If you profile an application and find out performance degradations are caused by excessive load on the server, optimizing the WAN is not going to really help. Reducing the load on the server, however, will. While it is certainly the case that improving transfer speeds over the WAN can ensure that some of the load is alleviated by clearing out server queues faster, it won't solve the entire problem because some of the degradation is caused by excessive context switching and compute time sharing between threads and processes on a server. While optimizing the WAN isn’t going to help you tackle that, reducing the number of those threads and processes required will.
Application delivery is about the bigger picture – and the focal point of that picture is the application. WAN optimisation has a role to play in that picture, but it is a supporting role, just like network optimisation and web acceleration. WAN optimisation is not and cannot be separated from application delivery. It simply is not a stand-alone technology – or at least not one that really enables organisations to realise real benefits with respect to performance and availability of applications. It's a piece of the larger picture that is application delivery.
For some applications – and uses – WAN optimisation will provide the biggest gains in performance. Transferring large data sets such as those related to backups and DR efforts, or virtual machines in long-distance migration efforts, need the assistance of WAN optimisation solutions. For others, however, such technology does very little to improve performance. That is why application delivery focuses on the big picture – the application and the context in which it is accessed. Without a holistic approach to application delivery you may be making one piece of the puzzle better – or you may be just spinning your technological wheels.
Adrian Noblett is APAC solution architect for F5 Networks.