What are the parameters of QoS - Quality of Service?

With the arrival of the new technologies, applications and services in the field of networking, the competition is rising rapidly. Each of these technologies, services and applications are developed with an aim of delivering QoS (quality of service) that is either better with the legacy equipment or better than that. The network operators and the service providers follow from trusted brands. Maintenance of these brands is of critical importance to the business of these providers and operators. The biggest challenge here is to put the technology to work in such a way that all the expectations of the customers for the availability, reliability and quality are met and at the same time the flexibility for quick adaptation of the new techniques is offered to the network operators. 

What is Quality of Service?

- The quality of service is defined by its certain parameters which play a key role in the acceptance of the new technologies. 

- The organization working on several specifications of QoS is ETSI.

- The organization has been actively participating in the organization of the inter-operability events regarding the speech quality.

- The importance of the QoS parameters has been increasing ever since the increasing inter-connectivity of the networks and interaction between many service providers and network operators for delivering communication services.

- It is the quality of service that grants you the ability for the making parameters specifications based up on multiple queues in order to shoot up the performance as well as the throughput of wireless traffic as in VoIP (voice over internet), streaming media including audio and video of different types. 

- This is also done for usual IP over the access points.

- Configuration of the quality of service on these access points involves setting many parameters on the queues that are already there for various types of wireless traffic. 

- The minimum as well as the maximum wait times are also specified for the transmission. 

- This is done through the contention windows. 

- The flow of the traffic between the access point and the client station is affected by the EDCA (AP enhanced distributed channel access) parameters. 

- The traffic flow from client to the access point is controlled by the station enhanced distribution channel access parameters. 

Below we mention some parameters:

Ø  QoS preset: The options listed by the QoS are WFA defaults, optimized for voice, custom and WFA defaults.

Ø  Queue: For different types of data transmissions between AP – to – client station, different queues are defined:

- Voice (data 0): Queue with minimum delay and high priority. Data which is time sensitive such as the streaming media and the VoIP are automatically put in this queue.

- Video (data 1): Queue with minimum delay and high priority. Video data which is time sensitive is put in to this queue automatically.

- Best effort (data 2): Queue with medium delay and throughput and medium priority. This queue holds all the traditional IP data. 

- Background (data 3): Queue with high throughput and lowest priority. Data which is bulky, requires high throughput and is not time sensitive such as the FTP data is queued up here.

Ø AIFS (inter-frame space): This puts a limit on the waiting time of the data frames. The measurement of this time is taken in terms of the slots. The valid values lie in the range of 1 to 255.

Ø Minimum contention window (cwMin): This QoS parameter is supplied as input to the algorithm for determining the random back off wait time for re-transmission.

Ø cwMax

Ø maximum burst

Ø wi – fi multimedia

Ø TXOP limit

Ø Bandwidth

Ø Variation in delay

Ø Synchronization

Ø Cell error ratio

Ø Cell loss ratio

What is Polling?

- Polling is often referred to as the polled operation.

- When the statuses of the external devices are actively sampled by a client program just like a synchronous activity is referred to as the polling. 

- The common use of the polling is in the input and output operations. 

- In rare cases, polling is also called as the software driven I/O or just simply as polled I/O. 

- As and when required, polling is also carried out with the busy waiting synonymous. 

- Polling is then referred to as the busy–wait polling. 

- In this case whenever it is required to carry out an input/ output operation, the system just checks the status of the device required for fulfilling this operation until it is idle. 

- When it becomes idle it is accessed by the I/O operation. 

- Such polling may also refer to a state in which the status of the device is checked again and again for accessing it if idle. 

- If the device is occupied, the system is forced to return to some other pending task. 

- In this case the CPU time is wasted less when compared to what happens in busy waiting. 

- However, this is not a better alternative to interrupt driven I/O polling. 

- In single purpose systems that are too simple, using busy-wait polling is perfectly fine if the system cannot take any action until the I/O device has been accessed. 

- But traditionally, the polling was thought to be a consequence of the operating systems and simple hardware that do not support multitasking. 

- The polling works intimately with the low level hardware usually. 

- For example, a parallel printer port can be polled for checking whether or not it is ready for printing another character. 

- This involves just the examination of a bit. 

- The bit to be examined represents the high or low voltage stage of the single wire in the cable of the printer during the time of reading. 

- The I/O instruction by which this byte is read is also responsible for transferring the voltage state directly to the eight flip flops or circuits. 

- These 8 flip flops together constitute one byte of a register of CPU. 

Polling also has a number of disadvantages. 

- One is that there is limited time for servicing the I/O devices. 

- Polling has to be done within this time period only. 

- But in some cases there are many devices to be checked which cause the polling time to exceed the given limit. 

- The host keeps on hitting the busy bit until the device becomes idle or clear. 

- When the device is idle, the state is written in to the command register and also in the data out register. 

- The command ready bit is set to 1. 

- The controller sets the busy bit once it knows that the command ready bit has been set.  

- After reading from the command register, the controller carries out the required I/O operation on the device. 

- On the other hand, if the read bit has been set to one, the controller loads the device data in to the data in register. 

- This data is further read by the host. 

- Once the whole action has been completed, the command ready bit is cleared by the controller. 

- The error bit is also cleared for showing that the operation has been completed successfully. 

- At the end the busy bit is also set.

- Polling can be seen in the terms of master slave scenario where the master sends inquiring about the working status slave devices i.e., whether they are clear or engaged. 

What is meant by Dynamic Virtual Private Network?

Dynamic virtual private network or DVPN is a network used for interconnecting various virtual application networks. 

- These networks reduce the need for manual configuration by a large percentage (almost by 93 %). 

- Dynamic virtual private networks help a great deal in the simplification of the wide area connectivity spread across a virtual application network.

- These networks have a great complexity when compared to the other networks.

- Further, they prove useful in establishing interconnections between various campuses, data centers, and offices and so on via IPsec VPN encryption. 

- The solution offered by the DVPNs is quite scalable, simple and secure. 

- The dynamic virtual private networks are highly automated and therefore provide a simple management solution. 

- A DVPN can scale up to 1000 – 3000 sites on a single router. 

- All these sites together constitute the domain of the DVPN. 

- So it is obvious that a very large network can be scaled via multiple DVPNs. 

- The best thing about these DVPNs is that they support all the WAN technologies and therefore can be implemented up on all.

- Furthermore, they offer flexibility in reducing the cost when compared to the lower cost broadband access.

- All the network operations are simplified since DVPN has automated VPN setup plus provisioning.

- DVPNs offer high resilience without adding to the complexity of the network. 

- Another characteristic feature of a dynamic virtual private network is its carrier agnostic connectivity.

- One solution to DVPN is offered by HP that has got the following features:

1. Full mesh or hub – spoke configuration
2. Encryption based up on IPsec standards.
3. The control plane and the data plane have been separated to ensure scalability.
4. Up to 30,000 clients are supportable by the VAM (VPN address management) server.
5. Offers zero touch configuration.

- Another solution is offered by the Juniper networks. 

- Juniper’s DVPN is more of a client-less solution and has been designed for ‘remote access’ IPsec VPN. 

- The delivery of the client to the end users is made dynamically from SRX. 

- The remote access is simplified by DVPN since it provides the users the facility to secure the IPsec VPN tunnels without any need for configuring the VPN settings on their systems. 

- This whole process comes in to when the users login to the server’s web site. - Juniper’s DVPN solution can be licensed to 5, 10, 25 or 50 concurrent users. 

- It supports windows xp and above versions (both 32 and 64 bit).

- However, there are certain limitations for this solution:

1. It requires an external RADIUS server for providing an IP address and for XAUTH.
2. Does not support shared IKE id.
3. Mandatory PFS (perfect forward secretary).
4. Requires custom IKE/ IPsec security proposals.
5. Only IKE – id supported is the FQDN.

- Configuration for DVPN is required only on the SRX gateway.

- Dynamic virtual private network is more of an intranet enabler whose purpose is to complement the regular services offered by the internet by adding more services as well as resources to it. 

- One major feature of these networks is that they have an excellent ability of loading balance on – the – fly allocation of the resources. 

- These networks are more popular in businesses since they offer more security by means of packet encryption protocols. 

- Self – modification is possible for the DVPNs and so they are able to recognize the added nodes without help from routers.

- Encryption and authentication are two technologies used by DVPNs for securing packing data and delivering across the networks. 

- Until the data reaches it destination it remains unpacked or encapsulated. 

- For reaching the remote networks tunneling is used. 

Explain Jubula - Web Functional/Regression Test Tool

Today we have around 100 tools available for functional and regression testing of the web based applications. Jubula is one among such tools and will be discussed here in detail. 

About Jubala

- This is an open source tool that is available both as a standalone application and as a part of the eclipse package.  

- The former comes with an installer that is quite easy to use and the latter one can be downloaded from an update site. 

- Jubula client can be used for viewing the actual and the expected results and also it can be used for viewing the current as well as the previous results. 

- Here, you can easily the automatic screenshots whenever an error occurs. 

- Jubula supports many applications such as:

1. Html
2. Swing
3. SWT/ RCP/ GEF and so on.

- Some features of Jubula tool have been listed below:

1. Heuristic object recognition
2. Command line client
3. Context sensitive help in client
4. Multi – user database for storing projects
5. Portability
6. Version control

- Command line has been included in this tool so as to facilitate continuous integration.

- Version control is achieved via the exports in XML format. 

- The contribution in this regard was made by BREDEX GmbH (also the developer of GUI dancer). 

- The GUIdancer was actually built up on the lines of Jubula core and offer some more features. 

- Jubula is not dependent on any platform windows, unix, linux or MAC. 

- A project by the name of ‘jubula functional testing tool’ was created as an open source project. 

- This project was a part of the eclipse technology project. 

- Other functional testing tools work up on the thing that the saving and management of the scripts is done through coding. 

Now depending up on the testing approach you are following, your test automation process may involve steps like recording, generation or straightaway writing of the code. 

What differentiates Jubala from other testing tools?

- It considers the importance of the automated acceptance tests as same as that of the project code. 

- According to Jubula, same best practices (reusability, modularity, readability etc.) should be used for creating these tests as well without requirement of any extra code. 

- Thus, the power of testing is given in the hands of the software testers and at the same time for the customers the access improves for monitoring the tests. 

- This results in a code free approach that minimizes the need for test maintenance, thus allowing the users to write the tests from their perspective. 

- If the team focuses on the software from the viewpoint of the user, it can gains a whole lot of quality info which often goes un-utilized when only JUnit tests are run.

- Jubula comes with a library of actions which is used for creating the tests. 

- You can combine the actions contained in the library using drag and drop.

- This library contains all the necessary actions that one may require for writing the tests. 

- This library is also independent of platform and application which implies that you can start writing the tests before the software is actually made available to you. 

- When you work with Jubula, you save on time since as soon as the code is committed the tests can be executed. 

- The time between the introduction of an error and catching it is reduced.

Objectives of Jubala

Jubula has got the following objectives:

1. Providing tooling for carrying out automated GUI testing on html and java based applications.
2. Specifying and maintaining a model specifications and requirements of the tests.
3. Providing API for projects so that the test scenarios can be generated, test can be executed and results can be obtained. 

What are the features of Telerik Test Studio?

About Telerik Test Studio

- Telerik test studio is a software testing tool that has been developed for carrying out different  kinds of testing such as the functional testing for web and desktop applications, performance testing, mobile application testing and load testing etc. 

- Telerik developed it to suit all kinds of web and desktop applications eliminating the need for writing the code.

- This testing tool lets you build easy collaboration between the QA professionals and the software developers. 

- The tool has been built in such a way so as to support several web technologies such as the HTML, Silverlight, javascript, asp.net and ajax. 

Features of Telerik Test Studio

1. The test recording in test studio does not depend on the scripts.
2. It supports cross – browser testing for a number of browsers such as Mozilla Firefox, Chrome, Internet explorer and safari.
3. Application testing is supported for applications developed in HTML, Silverlight, asp.net MVC and ajax.
4. It supports the web element abstraction and focuses on reusing them.
5. The test studio can be integrated with the 2008 and 2010 editions of the visual studio.
6. The tool can be integrated with the Nunit, Xunit and MbUnit.
7. The test studio validates the user interface based up on the sentences.
8. It has got a visual storyboard that lets the team members know about the progress done so far.
9. It supports the customization of the test in vb.net and C#.
10. It can also be used to carry out exploratory testing.
11. Telerik test studio can be integrated with the HP quality center.
12. It can also be integrated with the Telerik Team pulse.

- In other words, Telerik test studio provides one simple solution for most of the testing needs. 

- A special version of the test studio called the test studio for iOS has been developed using which the developers can create tests for apple products. 

- Using this tool, the developers can carry out the testing directly on the device. 

- Here, the element detection is not based up on image.

- Instead, object based recording is used.

- It supports development platforms such as the monotouch, Xcode and phonegap.

- One can test both the native and hybrid apps.

- For creating load tests you can either capture them or use the fiddler logs.

- You can run the functional tests as the performance tests and gather data regarding the client rendering time, network latency and server processing time.

- It is quite easy to get started with and quite easy to use too. 

- To create even the most complex functional, performance and load tests what that it all takes is navigation, pointing and clicking. 

- The test studio further helps in streamlining the teamwork by providing a common platform on which the developers and testers can work together. 

- Another thing about telerik test studio, it fits any budget since in one software testing tool you get the both performance and functional testing tools. 

- The license of this tool is quite affordable and can be easily obtained. 

- Some other features of test studio are:

1. Lightswitch – powered apps automation
2. Multi – browser support
3. Manual testing
4. Telerik controls automation
5. Provides native support for the kendo UI widgets
6. Data – driven testing
7. Support for browser dialog and html popups
8. Support for frames and frame sets
9. Historical view of the tests
10. Test customization
11. Single virtual user license type
12. Reporting dashboard
13. GUI test recorder
14. Visual studio professional and team system integration
15. Simple interface
16. Built – in data grid
17. Code-less conditional logic support

Explain Telerik Test Studio? What kinds of testing are supported by Telerik Test Studio?

About Telerik Test Studio

- Telerik test studio is another in the line of software testing tools. 

- This testing tool has been developed by Telerik test studio for performing functional testing for web and desktop, load testing, performance testing, mobile application testing and so on. 

- This software testing tool can be used to test all kinds of desktop and web applications. 

- This software testing tool can be used to test all kinds of desktop and web applications without having to write the test code. 

- The Telerik tool eases the collaboration between the quality assurance people and the software developers.

- A number of web technologies such as AJAX, HTML, ASP.NET, javascript, MVC and Silverlight are supported by the Telerik test studio. 

What kind of testing are done by Telerik Test Studio?

This tool can be used to carry out the following kinds of testing:

1. Functional Testing: 

- Almost any application (including AJAX, MVC, WPF, Silverlight and HTML) can be automated using Telerik. 

- In addition to the applications, it also supports the visual studio 2010.  

- Telerik comes with a plug – in for visual studio plus a standalone application that can be used by QA professionals for creating tests for cross browser testing. 

- These tests can be customized via visual studio or they can be converted in to unit tests.

- Most QAs use the Telerik test studio for testing the AJAX and asp.NET applications along with the client – side functionality. 

- They are also used for binding the test steps on to a data source. 

- The java script functions can be directly invoked and validated from the .net code.

- Telerik is even a Silverlight UI testing automation tool that does not depends up on the code.

- The tool comes with a rich UI object model because of which the users are able to automate the tests for the entire range of the UI elements. 

- The tool after plugging in to the Silverlight application directly can automate and access all the elements present in the Silverlight application.

- Telerik test studio has made it possible to test the reliability of the java apps. 

- It has got built – in translators for the following:

             a)    HTML5 controls

             b)    Cross – browser support

             c)    Javascript event handling

            d)    Codeless test automation of the various multimedia elements.

- Telerik makes the collaboration between the QAs and software developers effortless even if there location is not same.

- Both the visual studio plug – in and application make use of the same file formats and repositories.

- This allows the QAs to keep a check of the tests in the main application while the software developers can extend it with the code. 

- It becomes easy for the team members to know what has already been recorded by the other members via the built – in visual storyboard tool.

2. Performance Testing

- Telerik allows the analyzation of the metrics on the client and the server side, exploration of the traffic requests and counter data.

- It allows you to compare the results to the already defined benchmarks for goal setting or regression detection. 

- The existing UI tests can be supplemented with the performance metrics so that the data such as the network latency, server processing time, client rendering time etc. can be included.

3. Load testing

- Telerik test studio can be used to build tests up on the existing ones and run them so as to get a better understanding of the performance of their website under extreme conditions. 

- The load agents of the telerik test studio make use of the hyper threaded and multi-core CPUs for generating a very high user load.

4. Test studio for iOS

- This is a special version developed for automated testing of the iPad, iPhones and so on. 

How to run the silk scripts?

Silk test as we know is a test automation tool from the Borland which was launched in the year of 2006. This tool facilitates the automated regression testing and functional testing. However, the credit for the original creation goes to the segue software.

Various clients are offered by the silk test as described below:

1. Silk test classic: This client of the silk test makes use of the domain specific language called “4test” for scripting of the test automation scripts. This language just like the C++ language is an object oriented language. Just like C++ it also makes use of the Object Oriented concepts such as following:

a)   Inheritance

b)   Classes and

c)   objects

2. Silk 4J: This client of the silk test enables one to follow test automation by using java as the scripting language in eclipse.
3. Silk 4 net: This client of the silk test also enables one to follow test automation by using VBScript or sometimes using C# as the scripting language in the visual studio.
4. Silk test work bench: This client of the silk test enables the testers to carry out the automation testing using VB.net as the scripting language as well as on a visual level.

What kind of files a silk script consists?

In this article we are going to see how the execution of the test scripts takes place in silk test.

-  A basic or a typical silk script consists of two files namely:

1. Include file and
2. Script file

- The include file of the silk script is saved with an extension .inc and is particularly for the declaration of the following:

1. Window names
2. Window objects
3. Variables
4. Constants
5. Structures
6. Classes and so on.

- The second file i.e., the script file contributes in writing of the scripts. 

- It is saved by the extension .t and is used for defining of the body of the scripts. 

- Test cases meeting the various test conditions are defined in this script. 

- The two different types of files have been used to maintain the clarity of the code as much as possible. 

- If the include file of the test script does not consists of any of the test cases then the file may be compiled but cannot be executed. 

- If tried for the execution an error will be generated saying that there are no test cases. 

- Only the include file which consists of some test case can be run. 

- Before you run the script always make sure that you make separate declaration for the files:

1. For the declaration of the objects and
2. For creation of the scripts using declaration file.

Steps for running Test Scripts

After the two declarations have been made you should proceed for their compilation. Below we are stating the steps that are to be followed for running the test scripts:

1. Launch the silk test automation tool.
2. Open the script file of the script to be executed.
3. Compile the above script by using the compile option from menu bar.
4. Once the compilation of the file is complete the status of the script can be checked by the progress status.
5. Any errors present in the script will be displayed at the end of the compiling process.
6. Now run the silk scripts by clicking the run option in the menu bar.
7. For running the test scripts you have two options: either you can run all of them at a single stretch or you can run them selectively.
8. If you have opted for the latter option then you need to specify which all tests have to be executed.
9. After selection you can again give the run command. 

Is load testing possible using WinRunner? Does WinRunner help you in web testing?

Winrunner, apart from just serving as a test automation tool has also proved itself to be quite an effective tool for load testing. However, the winrunner can function as a load testing tool only at the level of the graphical user interface layer.  

Why it is so?

- This is so because at this level only the record and play back options are possible as if they are being carried out by a real world human user. 

How is load testing possible using WinRunner?

- The loadrunner counterpart of the winrunner is the proper load testing tool but sometimes winrunner is also used as one in addition to it. 

- Firstly, a user session such as a web browsing session is simulated. 

- The user actions taking place are recorded by the winrunner and are used for load testing. 

- No action is taken at the protocol layer by the wirnunner except recording and playing back of the events and all this seems as if some invisible real world human user is performing all these actions. 

- For the winrunner to perform load testing, it is required to give the control of the pc to it so that it can execute the previously recorded test scripts. 

- But at the same time a load test cannot be run in winrunner as a means of load generation. 

- The number of PCs required is directly proportional to the load that has to be given to the software system or application. 

- In spite of this disadvantage the winrunner will always be valued as a good load testing technology which provides the only means for the determination of the actual user response time. 

- The actual user response it calculates is inclusive of the processing that takes place on the side of the client hardware.

How WinRunner helps you in web testing?

- The context sensitive operations on the web (HTML) objects present in the web site can be recorded and run by the winrunner when it is loaded among with the web test add- in support. 

- This works if the web site in the browsers such as the internet explorer and Netscape. 

- With the help of the web test add- in, the properties of the web objects can be viewed and the information regarding the web objects present in the web site can be retrieved. 

- The check points can be created on the web objects present in the web site for the testing of the functionality of the web site. 

- Apart from internet explorer and netscape, the web browser AOL can be used for running tests and recording the objects in the web site but cannot be run or recorded on the following web browser elements:

1. Back button
2. Forward buttons
3. Navigate buttons and so on.

- When the tests are created using the web test add- in the below mentioned objects are recognized by the winrunner:

1. Text links
2. Frames
3. Images
4. Web form objects
5. Tables and so on.

- Different properties are possessed by every object. 

- These properties form a key aspect in the following tasks:

1. identification of the objects
2. Retrieval and checking of the property values.
3. Performing web functions.

- All the above three tasks ensure that your web site is working perfectly or not. 

- You should take care that you start the winrunner with the web test add- in loaded in before you open your web browser to start the web testing. 

- The recorded tab of the GUI spy can be used for viewing the properties and values of the properties that were recorded by the winrunner for the selected GUI objects.

- This is how the winrunner makes it possible to do the web testing.