Masters Thesis Seminar 123/05/2012 Masters Thesis Seminar

Usability and User Interface Development for Packet Core Network Element

Author: Taha OthmanSupervisor: Prof. Jukka MannerInstructor: Bernardo Di Chiara Place: Nokia Siemens Networks, Espoo

23 May 2012, EspooMaster’s Thesis Seminar

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Contents Background

User Centered Design Objective Usability Usability Engineering Lifecycle Result Solutions Conclusion Future work

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BackgroundAccording to Alan Cooper:“Most software conforms to implementation models”.

“User interfaces that conform to implementation models are bad”

In this thesis, the user will be taken into consideration in all activities:

The UCD (user-centered design) is used

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User -Centred Design

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Objective

To Create a user interface for the configuration management of SGSN Create use case. Benchmarking Design Prototype Usability testing

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Usability

It is a measurement of different attributes users experience when using a user interface: Learnability Efficiency Memorability Errors Satisfaction

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Usability Engineering Lifecycle No. Task Information produced

1 Know the user User characteristicsUser background

2 Know the task User’s current taskTask analysis

3 User requirement capture User requirements

4 Competitive analysis User requirements

5 Setting usability goals Usability specification

6 Design process Design

7 Heuristics evaluation Feedback for design

8 Prototyping Prototype for user testing

9 Evaluation with users Feedback for redesign

10 Iterative design (redesign and evaluate with users)

Finished product

11 Evaluate with users and report Feedback on product for future systems

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Defining Use Cases

External interfaces: Gr Gs Iu

Features: Statistics Tracing Charging

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BenchmarkingNo. Item in Nielsen’s heuristic Viewpoint of evaluator regarding the

Cisco CLI1 Simple and natural dialog It fulfils very well this item

2 Speak the user’s language It does not match with the real world

3 Minimize the user’s memory load It fulfils this item

4 Consistency This item is fulfilled. Commands work in consistent way

5 Feedback This item is fulfilled. System status and changes are print out on the console

6 Clearly marked exits This item is fulfilled: “Ctrl-C” or “Ctrl-Z” almost works anywhere and the user would be able to exit

7 Usage of shortcuts This is strongly fulfilled. There are many shortcuts and hot keys

8 Good error messages This is almost fulfilled. Error messages are not always self-evident

9 Prevent Errors This is almost fulfilled

10 Help and documentation Help texts are found within every command tree branch

11 Free comments (strength) Cisco CLI is robust, consistent, simple, easy to learn, user handy interface. Cisco CLI is defacto in the telecom field

12 Free comments (weakness) In configuration mode, when updating the configuration it is somehow difficult to see the changes

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Setting Usability Goals The structure of CLI must be organized in a logical way

The information must be present in a clear way on the screen

The terminology and information must be consistent in CLI

CLI learning experience must be easier and learning time is easier

CLI must be designed in a way that reduces the effort needed by the user to memorize

CLI must provide proper help and proper feedback in case of successful and unsuccessful scenarios

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Design 1/4: The principle of metaphor “Borrowing behaviors from systems familiar

to the users” Cisco like structure framework

Framework functionality: Auto completion Context sensitive help Secure CLI access Executed CLI’s history Validation for the command structure

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Design 2/4: The principle of coherence “Consistency refers to unification of the general

operation sequence, terminology, components, layout, color and style sheets in the user interface”

This principle is implemented by the following: Implementing CLI framework Forming a usability committee Look and feel guidelines

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Design 3/4 : The principle of grammar “ A user interface is a kind of language –

know what the rules are” Two constructions:

Action -> Object Object -> Action

In this study case, “Object -> Action” is implemented: It is natural way for people to think in object rather than verb It is more user-oriented as there is a good mapping between CLI

structure and user’s conceptual model

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Design 4/4 : Other design principle The principle of user profiling Strive for simplicity The principle of reducing memory load The principle of help The principle of informative feedback

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CLI structure

<domain> <operation> [rest of the command]

domain: the first token determining the functional area operation: the verb executed on the domain rest of command: optional tokens that can be decided for

each command

Example:sgsn interface gr-ss7 protocols mtp signaling-link configure <parameters>

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Prototype

The prototype is implemented for the mtp layer of SS7 protocol in Gr interface

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Usability testing The survey was sent to 10 engineers The respondents were 4 engineers. Two type of questions:

Self reported questions: Overall reaction CLI structure Layout and screen Terminology and CLI information Learning

Open-ended questions: Free comments List most negative aspects List most positive aspects

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Result

Aspect Status

Overall reaction CLI Neutral

CLI structure Almost satisfied

Layout and screen Not satisfied

Terminology and CLI information

- Satisfied with some aspects such as: • Consistency • Recovering from error situations- Not satisfied with some other aspects:• help

Learning Satisfied

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Problems

The same commands are present under different domain

The CLI screen is crowded with information Help is not enough “display all” command is missing

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Solutions Reduce 3 levels from the structure:

“sgsn interface gr-ss7 protocols mtp” It becomes “sgsn mtp”

New domain, monitor: sgsn monitor display <signaling-link><all> sgsn monitor display <ip-configuration>

Creating new commands: clear_screen

CLI look and feel Reduce the length of prompt

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Conclusion

It was difficult to identify the real usability issues in the new CLI because of the small numbers of evaluators

The satisfaction of the evaluators varied from one aspect to another: Positive:

Learning experience CLI structure Consistency Recovering from error situations

Negative: Screen and layout Help provide in the CLI

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Future work

Implementing the proposed solutions and conduct another usability survey

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Thank You!