network-services

Top Five Broken AA NPM Promises

You may have noticed – through experience, product literature, website content, or marketing emails – that virtually all AA NPM solutions tout benefits from capabilities embedded in such themes as “User Experience,” “Application Performance,” or “Business Impact,” – with enticing dashboards and lots of metrics and graphs to grab (and perhaps distract) attention. (I’ll be the first to admit I’m a sucker for modern, fast and beautiful dashboards.) In fact,… read more

Top Five Benefits of Transaction-Centric NPM: A Recap

I recently participated in a webcast that I called the “Top Five Benefits of Transaction-Centric NPM” – resisting some internal pressure to use the more common “Application-Aware NPM” or AA NPM term. Google the term “Transaction-Centric NPM,” and you’ll be hard-pressed to find content beyond recent references to the webinar. I’m not attempting to coin a new acronym – TC NPM, anyone? Instead, my goal is to shed… read more

Understanding Application Performance on the Network – Part IX: Conclusion

One thing I learned – or more accurately, had reinforced – from the many comments on this blog series is that there are often subtle differences in the implementation of various TCP features and specifications; TCP slow-start and Congestion Avoidance are good examples, as is the retransmission of dropped packets (and even the Nagle algorithm). I have purposely tried to abstract the minutiae of the algorithms, describing instead their important… read more

Understanding Application Performance on the Network – Part VI: The Nagle Algorithm

In Part V, we discussed processing delays caused by “slow” client and server nodes. In Part VI, we’ll discuss the Nagle algorithm, a behavior that can have a devastating impact on performance and, in many ways, appear to be a processing delay. Common TCP ACK Timing Beyond being important for (reasonably) accurate packet flow diagrams, understanding “normal” TCP ACK timing can help in the effective… read more

Understanding Application Performance on the Network – Part V: Processing Delays

In Part IV, we wrapped up our discussions on bandwidth, congestion and packet loss. In Part V, we examine the four types of processing delays visible on the network, using the request/reply paradigm we outlined in Part I. Server Processing (Between Flows) From the network’s perspective, we allocate the time period between the end of a request flow and… read more

Filling Citrix Visibility Gap with Application-Aware Network Performance Monitoring: Part 2 – End-User Experience Monitoring

Citrix XenApp or XenDesktop are a perfect fit for lowering the costs of desktop management and simplifying access to the hosted applications from any device. Last week we discussed some challenges to application performance monitoring (APM) introduced by Citrix. Apart from getting yet another component in the data center to take care of, the virtualized application delivery becomes “black boxed” from the APM perspective. It gets harder to isolate the fault domain to the network, the infrastructure, or the applications themselves. Today, we will look into monitoring end-user experience of applications delivered through Citrix. read more

Filling Citrix Visibility Gap with Application-Aware Network Performance Monitoring – Part 1: Load Balancing

There are many reasons why companies choose Citrix XenApp or XenDesktop. Citrix can lower the costs of desktop management and simplify access to hosted applications from any device. Citrix seems like an ideal solution but it introduces certain challenges to application performance monitoring (APM). With Citrix we get yet another component in the data center to take care of. In addition, the virtualized application delivery becomes “black boxed” from the APM perspective. It gets harder to isolate the fault domain to either the network, infrastructure or applications themselves. In this two-part series we will analyze how to discover and handle some performance issues which can happen in the Citrix enabled environment. We start by looking at how to monitor network performance to discover potential problems with load balancing. In the second part we will look into managing experience of Citrix users from the perspective of network monitoring. read more

5 Steps to Improve E-Commerce Performance for Increased Sales: Network Performance

This is the third episode of the mini-series on e-commerce performance management. Our client TescaraHats (name changed for commercial reasons), a European market leader in manufacturing customized hats, did not achieve the expected sales increase with its new e-commerce site. It offered its customers the ability to customize and order hats online instead of visiting its brick and mortar locations, but customers seemed disinterested. TescaraHats learned quickly that there is much more to an e-commerce platform than simply putting an e-commerce service online. In previous posts we showed that increasing page rank is not the only way to boost sales and that checking and improving backend performance of your e-commerce is also critical. In this episode we show why it you should not keep network load and HTTP errors in check. read more

Balancing the Load

A question that every online application provider will face eventually is: does my application scale? Can I add an extra 100 users and still ensure the same user experience? If the application architecture is properly designed the easiest way is to put additional server behind load balancer to handle more traffic. In this article we recount an incident that happened to one of our clients when the… read more

Let's Not Play Blame Games

When the Operations team gets an alert about potential performance problems that users might be experiencing, it is usually either the infrastructure or the actual application that is causing those problems. Things get interesting when neither the ISP nor the application provider is willing to admit fault. Can we tell who is to blame? Could it be that it is neither the ISP nor the application provider? The IT department… read more