Click here to close now.


@BigDataExpo Authors: Ken Simpson, Bob Gourley, Pat Romanski, Automic Blog, 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

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 Analysis at Compuware APM. He has global field enablement responsibilities for performance monitoring and analysis solutions embracing emerging and strategic technologies, including WAN optimization, thin client infrastructures, network forensics, and a unique performance management maturity methodology. He is also a co-inventor of multiple analysis features, and continues to champion the value of software-enabled expert network analysis.

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
Discussions of cloud computing have evolved in recent years from a focus on specific types of cloud, to a world of hybrid cloud, and to a world dominated by the APIs that make today's multi-cloud environments and hybrid clouds possible. In this Power Panel at 17th Cloud Expo, moderated by Conference Chair Roger Strukhoff, panelists addressed the importance of customers being able to use the specific technologies they need, through environments and ecosystems that expose their APIs to make true ...
In recent years, at least 40% of companies using cloud applications have experienced data loss. One of the best prevention against cloud data loss is backing up your cloud data. In his General Session at 17th Cloud Expo, Sam McIntyre, Partner Enablement Specialist at eFolder, presented how organizations can use eFolder Cloudfinder to automate backups of cloud application data. He also demonstrated how easy it is to search and restore cloud application data using Cloudfinder.
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo 2016 in New York and Silicon Valley. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 17th Cloud Expo and will feature technical sessions from a rock star conference faculty ...
Internet of @ThingsExpo, taking place June 7-9, 2016 at Javits Center, New York City and Nov 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 18th International @CloudExpo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world and ThingsExpo New York Call for Papers is now open.
Growth hacking is common for startups to make unheard-of progress in building their business. Career Hacks can help Geek Girls and those who support them (yes, that's you too, Dad!) to excel in this typically male-dominated world. Get ready to learn the facts: Is there a bias against women in the tech / developer communities? Why are women 50% of the workforce, but hold only 24% of the STEM or IT positions? Some beginnings of what to do about it! In her Day 2 Keynote at 17th Cloud Expo, San...
Cloud computing delivers on-demand resources that provide businesses with flexibility and cost-savings. The challenge in moving workloads to the cloud has been the cost and complexity of ensuring the initial and ongoing security and regulatory (PCI, HIPAA, FFIEC) compliance across private and public clouds. Manual security compliance is slow, prone to human error, and represents over 50% of the cost of managing cloud applications. Determining how to automate cloud security compliance is critical...
As organizations shift towards IT-as-a-service models, the need for managing & protecting data residing across physical, virtual, and now cloud environments grows with it. CommVault can ensure protection & E-Discovery of your data - whether in a private cloud, a Service Provider delivered public cloud, or a hybrid cloud environment – across the heterogeneous enterprise.
In his keynote at @ThingsExpo, Chris Matthieu, Director of IoT Engineering at Citrix and co-founder and CTO of Octoblu, focused on building an IoT platform and company. He provided a behind-the-scenes look at Octoblu’s platform, business, and pivots along the way (including the Citrix acquisition of Octoblu).
There are over 120 breakout sessions in all, with Keynotes, General Sessions, and Power Panels adding to three days of incredibly rich presentations and content. Join @ThingsExpo conference chair Roger Strukhoff (@IoT2040), June 7-9, 2016 in New York City, for three days of intense 'Internet of Things' discussion and focus, including Big Data's indespensable role in IoT, Smart Grids and Industrial Internet of Things, Wearables and Consumer IoT, as well as (new) IoT's use in Vertical Markets.
Today air travel is a minefield of delays, hassles and customer disappointment. Airlines struggle to revitalize the experience. GE and M2Mi will demonstrate practical examples of how IoT solutions are helping airlines bring back personalization, reduce trip time and improve reliability. In their session at @ThingsExpo, Shyam Varan Nath, Principal Architect with GE, and Dr. Sarah Cooper, M2Mi’s VP Business Development and Engineering, explored the IoT cloud-based platform technologies driving t...
The Internet of Things (IoT) is growing rapidly by extending current technologies, products and networks. By 2020, Cisco estimates there will be 50 billion connected devices. Gartner has forecast revenues of over $300 billion, just to IoT suppliers. Now is the time to figure out how you’ll make money – not just create innovative products. With hundreds of new products and companies jumping into the IoT fray every month, there’s no shortage of innovation. Despite this, McKinsey/VisionMobile data...
As organizations realize the scope of the Internet of Things, gaining key insights from Big Data, through the use of advanced analytics, becomes crucial. However, IoT also creates the need for petabyte scale storage of data from millions of devices. A new type of Storage is required which seamlessly integrates robust data analytics with massive scale. These storage systems will act as “smart systems” provide in-place analytics that speed discovery and enable businesses to quickly derive meaningf...
In his General Session at 17th Cloud Expo, Bruce Swann, Senior Product Marketing Manager for Adobe Campaign, explored the key ingredients of cross-channel marketing in a digital world. Learn how the Adobe Marketing Cloud can help marketers embrace opportunities for personalized, relevant and real-time customer engagement across offline (direct mail, point of sale, call center) and digital (email, website, SMS, mobile apps, social networks, connected objects).
The Internet of Everything is re-shaping technology trends–moving away from “request/response” architecture to an “always-on” Streaming Web where data is in constant motion and secure, reliable communication is an absolute necessity. As more and more THINGS go online, the challenges that developers will need to address will only increase exponentially. In his session at @ThingsExpo, Todd Greene, Founder & CEO of PubNub, exploreed the current state of IoT connectivity and review key trends and t...
Too often with compelling new technologies market participants become overly enamored with that attractiveness of the technology and neglect underlying business drivers. This tendency, what some call the “newest shiny object syndrome” is understandable given that virtually all of us are heavily engaged in technology. But it is also mistaken. Without concrete business cases driving its deployment, IoT, like many other technologies before it, will fade into obscurity.
In today's enterprise, digital transformation represents organizational change even more so than technology change, as customer preferences and behavior drive end-to-end transformation across lines of business as well as IT. To capitalize on the ubiquitous disruption driving this transformation, companies must be able to innovate at an increasingly rapid pace. Traditional approaches for driving innovation are now woefully inadequate for keeping up with the breadth of disruption and change facin...
The Internet of Things is clearly many things: data collection and analytics, wearables, Smart Grids and Smart Cities, the Industrial Internet, and more. Cool platforms like Arduino, Raspberry Pi, Intel's Galileo and Edison, and a diverse world of sensors are making the IoT a great toy box for developers in all these areas. In this Power Panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists discussed what things are the most important, which will have the most profound...
With all the incredible momentum behind the Internet of Things (IoT) industry, it is easy to forget that not a single CEO wakes up and wonders if “my IoT is broken.” What they wonder is if they are making the right decisions to do all they can to increase revenue, decrease costs, and improve customer experience – effectively the same challenges they have always had in growing their business. The exciting thing about the IoT industry is now these decisions can be better, faster, and smarter. Now ...
Apps and devices shouldn't stop working when there's limited or no network connectivity. Learn how to bring data stored in a cloud database to the edge of the network (and back again) whenever an Internet connection is available. In his session at 17th Cloud Expo, Ben Perlmutter, a Sales Engineer with IBM Cloudant, demonstrated techniques for replicating cloud databases with devices in order to build offline-first mobile or Internet of Things (IoT) apps that can provide a better, faster user e...
We are rapidly moving to a brave new world of interconnected smart homes, cars, offices and factories known as the Internet of Things (IoT). Sensors and monitoring devices will touch every part of our lives. Let's take a closer look at the Internet of Things. The Internet of Things is a worldwide network of objects and devices connected to the Internet. They are electronics, sensors, software and more. These objects connect to the Internet and can be controlled remotely via apps and programs. ...