virtual university of pakistan

Assignment No 5

Usability testing is one of the most significant ways of performing evaluation. Usability testing is conducted in controlled environment. There may be cases where it may not be possible to use such controlled environment.

Mobile usability testing is used in such circumstances. We can perform this by standard methods, active intervention and co-discovery but not in the lab environment, it can be tested by laptop having some software any and necessary hardware.

Let’s take an example from the telecommunication industry. There are two major categories of telecom companies. One is the vendor that basically is the developers and inventors of the software and hardware, whereas Operators are the second category of the industry that purchases telecom equipment from vendor. Vendors are normally responsible for installation and configuration of the equipment. The vendors perform the usability testing of the equipment in front of operators after installation and configuration to satisfy them.

Optix series equipment can be installed in a cabinet (300 mm or 600 mm deep)

Or a 19-inch standard cabinet. It can also be installed against the wall on the floor.

The cabinet consists of the sub racks that consist of the different cards those are responsible for the routing of the telecom traffic over the optical and electrical interfaces. After installation of equipment there is a phase where the inspection of installed equipment is done to check any faulty physical connections of the power cables & connectors, data traffic cables, positions of the optical and electrical interface cards, grounding cables, power box, cabinet is installed properly or not i.e. fixed well on ground and marking of cabinet in readiness.

The traffic routing cards can handle and process several users at a time and for every active card there is a back up card that is also called the protection card. This protection card is placed in the rack. If the working card gets faulty, the traffic switches on to the other card so that continuity of the calls didn’t interrupt.

There are different indicators on every card that shows the status of the card i.e. critical alarm, minor alarm,  major alarm, service not configured, working, power LED indicator, power on/off switch, Received signal loss, input power high, input power too low etc. If any error occurs during the transmission, indicators start blinking according to the nature of error. Before commercial usage the product is testified by generating error to check the alarms working properly or not, in same way to check the switching of the working card over the protection is testified by interrupting the traffic on the working card slot through the software. There are many test conducted during the usability testing i.e. Power-on Functioning of the Rack, Average Optical Power Transmition, Actual Received Optical Power, E1 or electrical cable Tributary Test and Cabling Test, E3/STM-1 Tributary Test and Cabling Test, Power Input Unit Protection, Fan Rotational Speed Automatically Adjustment network Management Function Test, Configuration Management Alarm Management, Security Management .To make the route on the system before use there is a slot for testing and configuration where laptop can be connected to the system, problems are rectified through this port.

There is software also installed on the Laptop system to control and handle the configuration process through laptop. Different menus and tabs are given on the software to access different functions of the system. System is configured by making services through the specialized software, during this process cross connections among optical and electrical interfaces are done; protection and working cards are configured.

Questions:

By reading the above Scenario, answer the following Questions:

a)      There are different strategies adopted to prevent any disconnection in the traffic during failure of any card or cable, mention those.

b)      During usability test, how can a tester check the status of a card without connecting laptop having software or any testing equipment, i.e. say for example errors on optical interface card, having service error or the power received  low error  that occur when  the card is not receiving signal according to the standard.

c)      After installation and service configuration of the hardware, Testing of the equipment is done in the presence of engineers & Managers of the customer company for which system has been installed.  There are different test that are conducted when vendor of the product handover the equipment to there customers. Mention few test names.

d)     Telecom switches and other systems that basically route and process the telecom traffic are installed and configured in different steps. First there is a phase called the survey phase that is done to select the place where equipment has to be installed physically, than next phase of installation is started where data cables, power cables and racks are installed, finally the equipment is configured i.e. services are configured. There are some tools to configure services in the system, state how a newly installed system is configured.