|By Steve Weisfeldt||
|January 7, 2013 08:00 AM EST||
Mobile applications and mobile websites have become a major channel for conducting business, improving employee efficiency, communicating, and reaching consumers. In Part I of this article we discussed the differences between testing traditional and mobile applications, specific challenges associated with mobile load testing, mobile testing basics and best practices for recording mobile load test scenarios. In this Part 2 of the article, we will look at how to conduct realistic tests and how to best analyze the results.
How to Run Realistic Load Tests
Once you've recorded a mobile test scenario, you need to be parameterize it so that it can emulate users with different identities and behaviors as it is played back to produce a realistic load on the server. This step is required for traditional and mobile web applications, and the tools used to complete it are the same. When playing back the test scenarios, however, there are several challenges specific to mobile load testing.
Simulating Network Conditions
Today's mobile devices generally access the server over networks that are slower than those used by desktop computers. Network conditions have a significant effect on the user experience, and the effect may be more or less pronounced depending on the application. Network characteristics including bandwidth, latency and packet loss have a huge impact on client response times and on the way the server is loaded. By simulating different network conditions in a test lab environment you can forecast the effects of changes in the network infrastructure on the application's performance. Doing so also allows you to discover application issues in the development cycle, therefore reducing costs.
Bandwidth, Latency and Packet Loss
For example, low bandwidth increases the time it takes to download a resource, which then results in higher page load times. If the customer is connected longer, front-end servers hold sockets longer, load balancers have more active TCP sessions and application servers use more threads.
Mobile networks have limited bandwidth and high latency compared to Wi-Fi and broadband. Since the latency is a time added to each request and webpages are composed of many sub-requests, the time required to load a webpage on a mobile device greatly depends on the latency.
Limiting bandwidth and simulating latency and packet loss during a load test allows you to check that all of your users, including mobile users, will get the best user experience and acceptable response times while ensuring your servers won't have problems under load.
Bandwidth and Response Times
The bandwidth is directly correlated with how long it takes to download data from the server. The lower the bandwidth, the higher the response time. A server that provides acceptable response times for desktop users using DSL or another high-speed broadband service may deliver a poor end-user experience to mobile users with lower bandwidth.
It is important to validate your service-level agreements (SLAs) and performance objectives with tests that use the same bandwidth limitations as your users to avoid making decisions based on misleading test results. Such tests must incorporate bandwidth simulation, which is the process of artificially slowing down the traffic during a test to simulate a slower connection.
Bandwidth and Server Load
Clients using lower bandwidth connections also affect the server. The lower the bandwidth, the longer the connections. Longer connections, in turn, lead to more simultaneous connections on your web server and your application server. Thus, mobile users tend to consume more connections than their wired counterparts. Most servers have settings that limit the number of simultaneous connections that they can handle. Without a testing tool that realistically simulates bandwidth, these settings cannot be properly validated.
Simulating Bandwidth Limitations for Individual Virtual Users
When load testing, effective bandwidth simulation requires the ability to individually limit the bandwidth for each user or groups of users, independent of the others.
Consider a situation in which you need to verify performance when 100 mobile users are accessing the server. In this scenario, you'd want to simulate 100 virtual users, with each user limited to a 1Mbps 3G connection. In this case, the total bandwidth for all users is 100Mbps (100 users * 1Mbps/user). Though it is possible to use WAN emulation software or a network appliance to globally limit the bandwidth for the load generation machine to 100 Mbps (or any other arbitrary limit), in practice this does not provide a realistic test because it does not impose a strict 1Mbps constraint on each user. Bandwidth simulation support must be integrated in the load testing tool to enable bandwidth limits to be applied to individual virtual users.
To conduct an even more realistic test, you'll want to simulate a mixed population of users accessing your application with a variety of bandwidths. With a tool capable of bandwidth simulation on a per virtual user basis, you can determine the response times for users at each bandwidth across a range of bandwidths in a single test. This saves times when you need to compare the response times of web applications and business transactions for clients who have different bandwidth limits.
Simulating Browsers and Browser Capabilities
When a browser requests a resource from a web server, it identifies itself via the user-agent header sent with each request. This header contains information about the browser and the platform on which it is running. Servers use this information to deliver different versions of the content based on the client system. As noted earlier, many web applications deliver different content to mobile users and desktop users. Some further differentiate mobile users into subgroups based on information in the user-agent header, delivering less text and smaller images to devices with small screens. This can lead to bandwidth consumption and loading times that vary widely with the browser and platform being used.
As a result, the ability to manipulate the user-agent header is essential not only for recording test scenarios, but also for playing them back. Tools that lack this capability will fail to retrieve the appropriate content from the server.
Simulating Parallel Connections
Mobile browsers, like desktop browsers, can generate the HTTP requests needed to retrieve the static resources of a web page in parallel. Rather than waiting for each image to finish loading before requesting the next, this approach requests multiple images at once to shorten the overall page load time. To measure response times accurately, load testing tools must replicate this behavior by generating multiple requests in parallel. Moreover, they must simulate the appropriate number of parallel connections as this number may differ from one mobile browser to another. Again, tools that lack this capability are not performing realistic tests, placing the results they deliver into question.
Identifying the Most Appropriate Settings for Realistic Tests
Finding the appropriate values for key test settings - such as the user-agent, bandwidth, and number of simultaneous connections - can be a challenge. More advanced load testing tools can help testers set these values. For example, test scenario playback is greatly simplified by tools that can automatically inform the tester of which user-agent string and number of parallel connections to use based on the browser name, version, and platform. The process is further streamlined when the tools can suggest the most appropriate upload and download bandwidth settings based on the technology used (for example, Wi-Fi, 3G, 3G+, and so on) and the quality of the signal (for example, poor, average, or good).
Using the Cloud
You can use load testing with the cloud after (or in conjunction with) on-premise testing in the lab to improve the realism of your tests by generating high loads and testing from different locations, while saving time and lowering costs.
Generating a High Load
For consumer-facing apps and websites, it's often difficult to predict the number of users your applications will have to handle. Traffic spikes that results from a promotion, marketing campaign, new product release, or even unexpected social network buzz can be substantial. To generate a similar load in-house, you would need a significant investment in hardware. Using the cloud, you can generate the same high load using on-demand resources at a much lower cost.
Testing from Different Geographies
Your web application's real users likely access the server from many different geographical locations and use different networks. To properly validate the application and the server infrastructure, your virtual users should operate under similar real world conditions.
Testing the Entire Application Delivery Chain
When your real users are located outside the firewall, you should run your virtual users from the cloud to validate the parts of the application delivery chain that are not tested when testing from the lab, including the firewall, load balancers, and other network equipment.
Tools for Testing with the Cloud
While the cloud represents an opportunity to rapidly increase the scale and improve the realism of load testing at low costs, cloud testing is most effective when it's used to complement internal load testing. Note that the primary factor in the success of load testing with the cloud is not the move to the cloud, rather it's the tool you select and how well it uses cloud technology. In particular, it's best to select a solution that is integrated with multiple cloud platforms, enables in-house test assets to be reused in the cloud, and supports realistic, large-scale tests across multiple geographical regions.
The default results of a load test are frequently delivered as averages. For example, load testing tools will typically show what errors occurred and the average response times for a request, web page, or business transaction regardless of the type of users being simulated or the bandwidth available to them.
Because bandwidth may vary widely for the different kinds of users simulated, the errors and response times can also vary widely. Taking an average of results with significant variation does not provide an accurate picture of what is really happening. To gain meaningful insights and to validate your SLAs and performance requirements for each network condition, it is important to go beyond the default results and analyze the results for each kind of user.
In many ways, mobile load testing is similar to load testing classic web applications. As a result, testers can leverage much of their existing knowledge and reuse existing techniques - like using the cloud for realistic, large-scale tests. However, there are specific requirements for testing mobile applications that are not addressed by traditional load testing techniques. Recording mobile test scenarios, conducting realistic tests that simulate real-world bandwidth and browser characteristics, and properly analyzing the results are some of the key areas that require special attention for mobile applications. Addressing challenges in these areas is essential to ensuring mobile web applications are sufficiently tested prior to release and that they will perform well under load in production.
The Internet of Things 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 and how we integrate our thinking to solve complicated problems. In his session at 19th Cloud Expo, Craig Sproule, CEO of Metavine, will demonstrate how to move beyond today's coding paradigm ...
Jun. 29, 2016 07:00 PM EDT Reads: 389
The cloud market growth today is largely in public clouds. While there is a lot of spend in IT departments in virtualization, these aren’t yet translating into a true “cloud” experience within the enterprise. What is stopping the growth of the “private cloud” market? In his general session at 18th Cloud Expo, Nara Rajagopalan, CEO of Accelerite, explored the challenges in deploying, managing, and getting adoption for a private cloud within an enterprise. What are the key differences between wh...
Jun. 29, 2016 05:30 PM EDT Reads: 1,029
SYS-CON Events has announced today that Roger Strukhoff has been named conference chair of Cloud Expo and @ThingsExpo 2016 Silicon Valley. The 19th Cloud Expo and 6th @ThingsExpo will take place on November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. "The Internet of Things brings trillions of dollars of opportunity to developers and enterprise IT, no matter how you measure it," stated Roger Strukhoff. "More importantly, it leverages the power of devices and the Interne...
Jun. 29, 2016 04:15 PM EDT Reads: 411
"We work in the area of Big Data analytics and Big Data analytics is a very crowded space - you have Hadoop, ETL, warehousing, visualization and there's a lot of effort trying to get these tools to talk to each other," explained Mukund Deshpande, head of the Analytics practice at Accelerite, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Jun. 29, 2016 04:15 PM EDT Reads: 394
The idea of comparing data in motion (at the sensor level) to data at rest (in a Big Data server warehouse) with predictive analytics in the cloud is very appealing to the industrial IoT sector. The problem Big Data vendors have, however, is access to that data in motion at the sensor location. In his session at @ThingsExpo, Scott Allen, CMO of FreeWave, discussed how as IoT is increasingly adopted by industrial markets, there is going to be an increased demand for sensor data from the outermos...
Jun. 29, 2016 04:00 PM EDT Reads: 348
UAS, drones or unmanned aircraft, no matter what you call them — this was their week. Our news stream was flooded with updates on the newly announced rules and regulations for commercial UAS from the FAA. So, naturally we have dedicated this week’s top news round up to highlight some of our favorite UAS stories.
Jun. 29, 2016 03:02 PM EDT Reads: 264
Internet of @ThingsExpo has announced today that Chris Matthieu has been named tech chair of Internet of @ThingsExpo 2016 Silicon Valley. The 6thInternet of @ThingsExpo will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
Jun. 29, 2016 03:00 PM EDT Reads: 348
Basho Technologies has announced the latest release of Basho Riak TS, version 1.3. Riak TS is an enterprise-grade NoSQL database optimized for Internet of Things (IoT). The open source version enables developers to download the software for free and use it in production as well as make contributions to the code and develop applications around Riak TS. Enhancements to Riak TS make it quick, easy and cost-effective to spin up an instance to test new ideas and build IoT applications. In addition to...
Jun. 29, 2016 02:00 PM EDT Reads: 643
CenturyLink has announced that application server solutions from GENBAND are now available as part of CenturyLink’s Networx contracts. The General Services Administration (GSA)’s Networx program includes the largest telecommunications contract vehicles ever awarded by the federal government. CenturyLink recently secured an extension through spring 2020 of its offerings available to federal government agencies via GSA’s Networx Universal and Enterprise contracts. GENBAND’s EXPERiUS™ Application...
Jun. 29, 2016 02:00 PM EDT Reads: 377
In addition to all the benefits, IoT is also bringing new kind of customer experience challenges - cars that unlock themselves, thermostats turning houses into saunas and baby video monitors broadcasting over the internet. This list can only increase because while IoT services should be intuitive and simple to use, the delivery ecosystem is a myriad of potential problems as IoT explodes complexity. So finding a performance issue is like finding the proverbial needle in the haystack.
Jun. 29, 2016 01:15 PM EDT Reads: 339
When people aren’t talking about VMs and containers, they’re talking about serverless architecture. Serverless is about no maintenance. It means you are not worried about low-level infrastructural and operational details. An event-driven serverless platform is a great use case for IoT. In his session at @ThingsExpo, Animesh Singh, an STSM and Lead for IBM Cloud Platform and Infrastructure, will detail how to build a distributed serverless, polyglot, microservices framework using open source tec...
Jun. 29, 2016 12:30 PM EDT Reads: 549
Apixio Inc. has raised $19.3 million in Series D venture capital funding led by SSM Partners with participation from First Analysis, Bain Capital Ventures and Apixio’s largest angel investor. Apixio will dedicate the proceeds toward advancing and scaling products powered by its cognitive computing platform, further enabling insights for optimal patient care. The Series D funding comes as Apixio experiences strong momentum and increasing demand for its HCC Profiler solution, which mines unstruc...
Jun. 29, 2016 11:00 AM EDT Reads: 513
The IoT is changing the way enterprises conduct business. In his session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, discussed how businesses can gain an edge over competitors by empowering consumers to take control through IoT. He cited examples such as a Washington, D.C.-based sports club that leveraged IoT and the cloud to develop a comprehensive booking system. He also highlighted how IoT can revitalize and restore outdated business models, making them profitable ...
Jun. 29, 2016 11:00 AM EDT Reads: 471
Presidio has received the 2015 EMC Partner Services Quality Award from EMC Corporation for achieving outstanding service excellence and customer satisfaction as measured by the EMC Partner Services Quality (PSQ) program. Presidio was also honored as the 2015 EMC Americas Marketing Excellence Partner of the Year and 2015 Mid-Market East Partner of the Year. The EMC PSQ program is a project-specific survey program designed for partners with Service Partner designations to solicit customer feedbac...
Jun. 29, 2016 11:00 AM EDT Reads: 583
IoT offers a value of almost $4 trillion to the manufacturing industry through platforms that can improve margins, optimize operations & drive high performance work teams. By using IoT technologies as a foundation, manufacturing customers are integrating worker safety with manufacturing systems, driving deep collaboration and utilizing analytics to exponentially increased per-unit margins. However, as Benoit Lheureux, the VP for Research at Gartner points out, “IoT project implementers often ...
Jun. 29, 2016 10:45 AM EDT Reads: 558
"delaPlex is a software development company. We do team-based outsourcing development," explained Mark Rivers, COO and Co-founder of delaPlex Software, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Jun. 29, 2016 10:30 AM EDT Reads: 506
In his general session at 18th Cloud Expo, Lee Atchison, Principal Cloud Architect and Advocate at New Relic, discussed cloud as a ‘better data center’ and how it adds new capacity (faster) and improves application availability (redundancy). The cloud is a ‘Dynamic Tool for Dynamic Apps’ and resource allocation is an integral part of your application architecture, so use only the resources you need and allocate /de-allocate resources on the fly.
Jun. 29, 2016 10:00 AM EDT Reads: 1,291
Connected devices and the industrial internet are growing exponentially every year with Cisco expecting 50 billion devices to be in operation by 2020. In this period of growth, location-based insights are becoming invaluable to many businesses as they adopt new connected technologies. Knowing when and where these devices connect from is critical for a number of scenarios in supply chain management, disaster management, emergency response, M2M, location marketing and more. In his session at @Th...
Jun. 29, 2016 09:45 AM EDT Reads: 1,258
Machine Learning helps make complex systems more efficient. By applying advanced Machine Learning techniques such as Cognitive Fingerprinting, wind project operators can utilize these tools to learn from collected data, detect regular patterns, and optimize their own operations. In his session at 18th Cloud Expo, Stuart Gillen, Director of Business Development at SparkCognition, discussed how research has demonstrated the value of Machine Learning in delivering next generation analytics to imp...
Jun. 29, 2016 09:45 AM EDT Reads: 943
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life sett...
Jun. 29, 2016 09:15 AM EDT Reads: 1,459