Welcome!

@BigDataExpo Authors: Scott Allen, Elizabeth White, SmartBear Blog, John Esposito, Liz McMillan

Related Topics: Microservices Expo, Java IoT, Linux Containers, IoT User Interface, Agile Computing, @BigDataExpo

Microservices Expo: Article

Understanding Application Performance on the Network | Part 1

A foundation for network triage

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:

  1. Increased globalization, coupled with (in fact facilitated by) inexpensive bandwidth means that the network is becoming a more critical part of the business at the same time its constraint is shifting from bandwidth to latency.
  2. Many of the network devices - appliances - that sit in the path between remote offices and data centers are application-fluent, designed to enhance and speed application performance, often by spoofing application behaviors; in fact, many of these have evolved in response to problems introduced by increased network latency.

In an ideal world, your application performance management (APM) solution or your application-aware network performance management (AANPM) solution would automatically isolate the fault domain for you, providing all the diagnostic evidence you need to take the appropriate corrective actions. The reality is that this isn't always the case; intermittent problems, unexpected application or network behaviors, inefficient configuration settings, or just a desire for more concrete proof mean that manual troubleshooting remains a frequent exercise. Although it may seem like there are a near-unlimited number of root causes of poor application performance, and that trial and error, guesswork and finger-pointing are valid paths toward resolution, the truth is much different. In a series of network triage blog posts, I'll identify the very limited realm of possible performance constraints, explain how to measure and quantify their impact, illustrate these using network packet trace diagrams, and offer meaningful and supportable actions you might evaluate to correct the problem. Understanding how to detect these possible performance problems (there are twelve altogether) will help you troubleshoot faster, more accurately, with greater insight, while collaborating more effectively with your application and system peers.

In this introductory entry, I present the request/reply application paradigm assumption upon which most of the analyses depend, illustrate key packet-level measurements, and provide a list of the 12 bottleneck categories we'll discuss in future blog entries to the series.

Packet Flow Diagrams
Throughout the blog series I will be using packet flow diagrams to illustrate message flows on the network, often to emphasize TCP's influence on these flows. Some are drawings to illustrate concepts and theory, others are screenshots from Compuware's Transaction Trace Analysis that illustrate the pertinent performance bottleneck. The diagram conventions are simple:

  • Each arrow represents one TCP packet
  • Blue arrows are used to represent data packets
  • Red arrows are used to represent TCP ACK packets
  • The slope of the arrow represents network delay
  • Time flows from top to bottom

Terminology
We will frequently use the term "operation," which we define as the unit of work that an application performs on behalf of a user; we sometimes describe it as "Click (or Enter key) to screen update." Business transactions are made up of one or more operations; for example, a user may click through a series of screens (operations) to complete a customer order update. Operations are an important demarcation point, as they represent the unique performance dimension important to the business, to the user, and to IT. The time a user waits for the system to execute an operation impacts business transaction performance and therefore productivity, and is dictated by the performance of lower-level IT-managed hardware, software and services. Note that this terminology may differ somewhat from network probes that often use the term "transaction" to reference session-layer request-response exchanges, which we discuss next.

Request/Reply Paradigm
We assume a client/server or request/reply paradigm, with TCP as the transport; this covers virtually all of what we might refer to as interactive business applications. It would include, for example, web-based apps, "fat client" apps, file server access, file transfers, backups, etc. It specifically excludes voice and video streaming as well as the presentation tier of thin-client solutions that use protocols such as ICA and PCoIP.

For each operation, there will be at least one application-level request and one corresponding application-level reply. These can be considered application messages, sometimes referred to as application-layer protocol data units (PDUs). Consider a simple client-server operation. At the application layer, a request message is passed to the client's TCP stack (TCP socket) for segmentation (into packets), addressing, and transmission; these lower layer TCP stack functions are essentially transparent to the application. At the receiving end (the server), the data from the network packets is reassembled into the application layer message and delivered to the listener service for processing. Once processing is complete, the server application passes the reply message to the server's TCP stack, and the message contents are similarly segmented and transferred across the network to the client. The performance of these request/reply message exchanges is constrained by two factors; message processing (at the server or client) and message transmission (across the network).

It is helpful, then, to consider this request/reply message exchange as the basis for performance analysis; the reassembled messages represent our network-centric insight into the application, while the packets visible in the trace file inform us how efficiently the network transports these messages.

For further insight click here for the full article, and stay tuned for Part II.

More Stories By Gary Kaiser

Gary Kaiser is a Subject Matter Expert in Network Performance Analytics at Dynatrace, responsible for DC RUM’s technical marketing programs. He is a co-inventor of multiple performance analysis features, and continues to champion the value of network performance analytics. He is the author of Network Application Performance Analysis (WalrusInk, 2014).

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@BigDataExpo Stories
You think you know what’s in your data. But do you? Most organizations are now aware of the business intelligence represented by their data. Data science stands to take this to a level you never thought of – literally. The techniques of data science, when used with the capabilities of Big Data technologies, can make connections you had not yet imagined, helping you discover new insights and ask new questions of your data. In his session at @ThingsExpo, Sarbjit Sarkaria, data science team lead ...
In his session at @ThingsExpo, Chris Klein, CEO and Co-founder of Rachio, will discuss next generation communities that are using IoT to create more sustainable, intelligent communities. One example is Sterling Ranch, a 10,000 home development that – with the help of Siemens – will integrate IoT technology into the community to provide residents with energy and water savings as well as intelligent security. Everything from stop lights to sprinkler systems to building infrastructures will run ef...
SYS-CON Events announced today that Peak 10, Inc., a national IT infrastructure and cloud services provider, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Peak 10 provides reliable, tailored data center and network services, cloud and managed services. Its solutions are designed to scale and adapt to customers’ changing business needs, enabling them to lower costs, improve performance and focus inter...
Up until last year, enterprises that were looking into cloud services usually undertook a long-term pilot with one of the large cloud providers, running test and dev workloads in the cloud. With cloud’s transition to mainstream adoption in 2015, and with enterprises migrating more and more workloads into the cloud and in between public and private environments, the single-provider approach must be revisited. In his session at 18th Cloud Expo, Yoav Mor, multi-cloud solution evangelist at Cloudy...
Artificial Intelligence has the potential to massively disrupt IoT. In his session at 18th Cloud Expo, AJ Abdallat, CEO of Beyond AI, will discuss what the five main drivers are in Artificial Intelligence that could shape the future of the Internet of Things. AJ Abdallat is CEO of Beyond AI. He has over 20 years of management experience in the fields of artificial intelligence, sensors, instruments, devices and software for telecommunications, life sciences, environmental monitoring, process...
Increasing IoT connectivity is forcing enterprises to find elegant solutions to organize and visualize all incoming data from these connected devices with re-configurable dashboard widgets to effectively allow rapid decision-making for everything from immediate actions in tactical situations to strategic analysis and reporting. In his session at 18th Cloud Expo, Shikhir Singh, Senior Developer Relations Manager at Sencha, will discuss how to create HTML5 dashboards that interact with IoT devic...
So, you bought into the current machine learning craze and went on to collect millions/billions of records from this promising new data source. Now, what do you do with them? Too often, the abundance of data quickly turns into an abundance of problems. How do you extract that "magic essence" from your data without falling into the common pitfalls? In her session at @ThingsExpo, Natalia Ponomareva, Software Engineer at Google, will provide tips on how to be successful in large scale machine lear...
SYS-CON Events announced today that SoftLayer, an IBM Company, has been named “Gold Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. SoftLayer, an IBM Company, provides cloud infrastructure as a service from a growing number of data centers and network points of presence around the world. SoftLayer’s customers range from Web startups to global enterprises.
The IoTs will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, will demonstrate how to move beyond today's coding paradigm and share the must-have mindsets for removing complexity from the development proc...
SYS-CON Events announced today that Ericsson has been named “Gold Sponsor” of SYS-CON's @ThingsExpo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. Ericsson is a world leader in the rapidly changing environment of communications technology – providing equipment, software and services to enable transformation through mobility. Some 40 percent of global mobile traffic runs through networks we have supplied. More than 1 billion subscribers around the world re...
You deployed your app with the Bluemix PaaS and it's gaining some serious traction, so it's time to make some tweaks. Did you design your application in a way that it can scale in the cloud? Were you even thinking about the cloud when you built the app? If not, chances are your app is going to break. Check out this webcast to learn various techniques for designing applications that will scale successfully in Bluemix, for the confidence you need to take your apps to the next level and beyond.
There is an ever-growing explosion of new devices that are connected to the Internet using “cloud” solutions. This rapid growth is creating a massive new demand for efficient access to data. And it’s not just about connecting to that data anymore. This new demand is bringing new issues and challenges and it is important for companies to scale for the coming growth. And with that scaling comes the need for greater security, gathering and data analysis, storage, connectivity and, of course, the...
SYS-CON Events announced today that Fusion, a leading provider of cloud services, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Fusion, a leading provider of integrated cloud solutions to small, medium and large businesses, is the industry's single source for the cloud. Fusion's advanced, proprietary cloud service platform enables the integration of leading edge solutions in the cloud, including cloud...
The increasing popularity of the Internet of Things necessitates that our physical and cognitive relationship with wearable technology will change rapidly in the near future. This advent means logging has become a thing of the past. Before, it was on us to track our own data, but now that data is automatically available. What does this mean for mHealth and the "connected" body? In her session at @ThingsExpo, Lisa Calkins, CEO and co-founder of Amadeus Consulting, will discuss the impact of wea...
Unless you don’t use the internet, don’t live in California, or haven’t been paying attention to the recent news… you should be aware that self-driving cars are on their way to becoming a reality. I have seen them – they are real. If you believe in the future reality of self-driving cars, then continue reading on. If you don’t believe in the future possibilities, then I am not sure what to do to convince you other than discuss the very real changes that will roll out with the consumer producti...
SYS-CON Events announced today that Enzu, a leading provider of cloud hosting solutions, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Enzu’s mission is to be the leading provider of enterprise cloud solutions worldwide. Enzu enables online businesses to use its IT infrastructure to their competitive advantage. By offering a suite of proven hosting and management services, Enzu wants companies to foc...
SYS-CON Events announced today that DatacenterDynamics has been named “Media Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY. DatacenterDynamics is a brand of DCD Group, a global B2B media and publishing company that develops products to help senior professionals in the world's most ICT dependent organizations make risk-based infrastructure and capacity decisions.
The IoT has the potential to create a renaissance of manufacturing in the US and elsewhere. In his session at 18th Cloud Expo, Florent Solt, CTO and chief architect of Netvibes, will discuss how the expected exponential increase in the amount of data that will be processed, transported, stored, and accessed means there will be a huge demand for smart technologies to deliver it. Florent Solt is the CTO and chief architect of Netvibes. Prior to joining Netvibes in 2007, he co-founded Rift Technol...
We’ve worked with dozens of early adopters across numerous industries and will debunk common misperceptions, which starts with understanding that many of the connected products we’ll use over the next 5 years are already products, they’re just not yet connected. With an IoT product, time-in-market provides much more essential feedback than ever before. Innovation comes from what you do with the data that the connected product provides in order to enhance the customer experience and optimize busi...
SYS-CON Events announced today that Stratoscale, the software company developing the next generation data center operating system, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Stratoscale is revolutionizing the data center with a zero-to-cloud-in-minutes solution. With Stratoscale’s hardware-agnostic, Software Defined Data Center (SDDC) solution to store everything, run anything and scale everywhere...