Click here to close now.

Welcome!

IoT User Interface Authors: Pat Romanski, AppDynamics Blog, John Wetherill, Elizabeth White, Liz McMillan

Related Topics: Microservices Expo, JAVA IoT, Linux Containers, IoT User Interface, Agile Computing, BigDataExpo® Blog

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 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.


@CloudExpo Stories
If cloud computing benefits are so clear, why have so few enterprises migrated their mission-critical apps? The answer is often inertia and FUD. No one ever got fired for not moving to the cloud - not yet. In his session at 15th Cloud Expo, Michael Hoch, SVP, Cloud Advisory Service at Virtustream, discussed the six key steps to justify and execute your MCA cloud migration.
EMC Corporation on Tuesday announced it has entered into a definitive agreement to acquire privately held Virtustream. When the transaction closes, Virtustream will form EMC’s new managed cloud services business. The acquisition represents a transformational element of EMC’s strategy to help customers move all applications to cloud-based IT environments. With the addition of Virtustream, EMC completes the industry’s most comprehensive hybrid cloud portfolio to support all applications, all workl...
"People are a lot more knowledgeable about APIs now. There are two types of people who work with APIs - IT people who want to use APIs for something internal and the product managers who want to do something outside APIs for people to connect to them," explained Roberto Medrano, Executive Vice President at SOA Software, in this SYS-CON.tv interview at Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
The 5th International DevOps Summit, co-located with 17th International Cloud Expo – being held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA – announces that its Call for Papers is open. Born out of proven success in agile development, cloud computing, and process automation, DevOps is a macro trend you cannot afford to miss. From showcase success stories from early adopters and web-scale businesses, DevOps is expanding to organizations of all sizes, including the...
You often hear the two titles of "DevOps" and "Immutable Infrastructure" used independently. In his session at DevOps Summit, John Willis, Technical Evangelist for Docker, will cover the union between the two topics and why this is important. He will cover an overview of Immutable Infrastructure then show how an Immutable Continuous Delivery pipeline can be applied as a best practice for "DevOps." He will end the session with some interesting case study examples.
Docker is becoming very popular--we are seeing every major private and public cloud vendor racing to adopt it. It promises portability and interoperability, and is quickly becoming the currency of the Cloud. In his session at DevOps Summit, Bart Copeland, CEO of ActiveState, discussed why Docker is so important to the future of the cloud, but will also take a step back and show that Docker is actually only one piece of the puzzle. Copeland will outline the bigger picture of where Docker fits a...
SYS-CON Media named Andi Mann editor of DevOps Journal. DevOps Journal is focused on this critical enterprise IT topic in the world of cloud computing. DevOps Journal brings valuable information to DevOps professionals who are transforming the way enterprise IT is done. Andi Mann, Vice President, Strategic Solutions, at CA Technologies, is an accomplished digital business executive with extensive global expertise as a strategist, technologist, innovator, marketer, communicator, and thought lea...
Even though it’s now Microservices Journal, long-time fans of SOA World Magazine can take comfort in the fact that the URL – soa.sys-con.com – remains unchanged. And that’s no mistake, as microservices are really nothing more than a new and improved take on the Service-Oriented Architecture (SOA) best practices we struggled to hammer out over the last decade. Skeptics, however, might say that this change is nothing more than an exercise in buzzword-hopping. SOA is passé, and now that people are ...
Enterprises are fast realizing the importance of integrating SaaS/Cloud applications, API and on-premises data and processes, to unleash hidden value. This webinar explores how managers can use a Microservice-centric approach to aggressively tackle the unexpected new integration challenges posed by proliferation of cloud, mobile, social and big data projects. Industry analyst and SOA expert Jason Bloomberg will strip away the hype from microservices, and clearly identify their advantages and d...
There is little doubt that Big Data solutions will have an increasing role in the Enterprise IT mainstream over time. 8th International Big Data Expo, co-located with 17th International Cloud Expo - to be held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA - has announced its Call for Papers is open. As advanced data storage, access and analytics technologies aimed at handling high-volume and/or fast moving data all move center stage, aided by the cloud computing bo...
An effective way of thinking in Big Data is composed of a methodical framework for dealing with the predicted shortage of 50-60% of the qualified Big Data resources in the U.S. This holistic model comprises the scientific and engineering steps that are involved in accelerating Big Data solutions: problem, diagnosis, facts, analysis, hypothesis, solution, prototype and implementation. In his session at Big Data Expo®, Tony Shan focused on the concept, importance, and considerations for each of t...
While there are hundreds of public and private cloud hosting providers to choose from, not all clouds are created equal. If you’re seeking to host enterprise-level mission-critical applications, where Cloud Security is a primary concern, WHOA.com is setting new standards for cloud hosting, and has established itself as a major contender in the marketplace. We are constantly seeking ways to innovate and leverage state-of-the-art technologies. In his session at 16th Cloud Expo, Mike Rivera, Seni...
Containers Expo Blog covers the world of containers, as this lightweight alternative to virtual machines enables developers to work with identical dev environments and stacks. Containers Expo Blog offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. Bookmark Containers Expo Blog ▸ Here Follow new article posts on Twitter at @ContainersExpo
Compute virtualization has been transformational, yet security policy implementation and enforcement has lagged behind in agility and automation. There are a number of key considerations when implementing policy in private and hybrid clouds. In his session at 15th Cloud Expo, Malcolm Rieke, the Director of Product Management at Catbird, discussed the impact of this new paradigm and what organizations can do today to safely move to software-defined network and compute architectures, including: ...
In their session at @ThingsExpo, Shyam Varan Nath, Principal Architect at GE, and Ibrahim Gokcen, who leads GE's advanced IoT analytics, focused on the Internet of Things / Industrial Internet and how to make it operational for business end-users. Learn about the challenges posed by machine and sensor data and how to marry it with enterprise data. They also discussed the tips and tricks to provide the Industrial Internet as an end-user consumable service using Big Data Analytics and Industrial C...
Cloud and Big Data present unique dilemmas: embracing the benefits of these new technologies while maintaining the security of your organization's assets. When an outside party owns, controls and manages your infrastructure and computational resources, how can you be assured that sensitive data remains private and secure? How do you best protect data in mixed use cloud and big data infrastructure sets? Can you still satisfy the full range of reporting, compliance and regulatory requirements? In...
Storage administrators find themselves walking a line between meeting employees’ demands to use public cloud storage services, and their organizations’ need to store information on-premises for security, performance, cost and compliance reasons. However, as file sharing protocols like CIFS and NFS continue to lose their relevance, simply relying only on a NAS-based environment creates inefficiencies that hurt productivity and the bottom line. IT wants to implement cloud storage it can purchase a...
There has been a lot of discussion recently in the DevOps space over whether there is a unique form of DevOps for large enterprises or is it just vendors looking to sell services and tools. In his session at DevOps Summit, Chris Riley, a technologist, discussed whether Enterprise DevOps is a unique species or not. What makes DevOps adoption in the enterprise unique or what doesn’t? Unique or not, what does this mean for adopting DevOps in enterprise size organizations? He also explored differe...
The move to the cloud brings a number of new security challenges, but the application remains your last line of defense. In his session at 15th Cloud Expo, Arthur Hicken, Evangelist at Parasoft, discussed how developers are extremely well-poised to perform tasks critical for securing the application – provided that certain key obstacles are overcome. Arthur Hicken has been involved in automating various practices at Parasoft for almost 20 years. He has worked on projects including database dev...
Cloud Foundry open Platform as a Service makes it easy to operate, scale and deploy application for your dedicated cloud environments. It enables developers and operators to be significantly more agile, writing great applications and deliver them in days instead of months. Cloud Foundry takes care of all the infrastructure and network plumbing that you need to build, run and operate your applications and can do this while patching and updating systems and services without any downtime.