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Gary Kaiser

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Why a discussion around Application Performance Analytics? There's a lot of buzz in this industry around the topic of performance analytics - an informal subset of IT operations analytics (ITOA) - as a solution to the growing mountains of monitoring data and the increasing complexity of application and network architectures. At the same time, there exist many purpose-built performance analysis solutions. Many are domain-centric - server monitoring and network monitoring, for example - while some exhibit a key ITOA characteristic by incorporating and correlating data from multiple sources. Most perform some level of analysis to expose predefined insights. Application Performance Analytics: Viewed Through a Simple Framework In this blog, I'll outline a simple analytics framework that illustrates how network and application metrics can be derived from a network probe ("w... (more)

Understanding APM on the Network

In Part 6, we dove into the Nagle algorithm - perhaps (or hopefully) something you'll never see. In Part VII, we get back to "pure" network and TCP roots as we examine how the TCP receive window interacts with WAN links. TCP Window Size Each node participating in a TCP connection advertises its available buffer space using the TCP window size field. This value identifies the maximum amount of data a sender can transmit without receiving a window update via a TCP acknowledgement; in other words, this is the maximum number of "bytes in flight" - bytes that have been sent, are traver... (more)

IT Operations and Digital Disruption | @DevOps Summit #APM #DevOps

Transaction-Centric NPM: Enabling IT/Business Collaboration One of the consequences of digital disruption is that IT is propelled much closer to users, who expect applications and services to be available and to perform well anytime, anywhere, on any device. Communicating with the business now more than ever requires communicating with these users, and effective communication requires a clear understanding of their experience with the application services you deliver. But how well do you understand end-user experience? To answer that question, let's first define end-user experie... (more)

Understanding Application Performance on the Network | Part 1

As a network professional, one of your newer roles is likely troubleshooting poor application performance. For most of us, our jobs have advanced beyond network "health," towards sharing - if not owning - responsibility for application delivery. There are many reasons for this more justifiable than the adage that the network is first to be blamed for performance problems. (Your application and system peers feel they are first to be blamed as well.) Two related influencing trends come to mind: Increased globalization, coupled with (in fact facilitated by) inexpensive bandwidth me... (more)

Understanding Application Performance on the Network | Part 3

In Part II, we discussed performance constraints caused by both bandwidth and congestion. Purposely omitted was a discussion about packet loss - which is often an inevitable result of heavy network congestion. I'll use this blog entry on TCP slow-start to introduce the Congestion Window (CWD), which is fundamental for Part IV's in-depth review of Packet Loss. TCP Slow-Start TCP uses a slow-start algorithm as it tries to understand the characteristics (bandwidth, latency, congestion) of the path supporting a new TCP connection. In most cases, TCP has no inherent understanding of th... (more)