QoS-Aware Power-Optimized Path Selection for Data Center Networks (Q-PoPS)

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper addresses the relevant problem of Quality-of-Service preservation in case of implementation of power consumption optimization procedures in software defined Data Center Networks. Authors developed QoS-aware power-optimized procedure for path selection, intended to ensure requested QoS level for real time services while optimizing/minimizing power consumption. The model is implemented as prototype using POX software defined networking controller and is evaluated using the Mininet emulator. Authors validated their model using simulation results in three different cases: best-case (proposed procedure maintain power consumption at the same level while improving the QoS), midrange-case (replacing bottleneck links in a path experiencing delay while preserving real-time traffic quality and slight increase in power consumption) and worst-case (maintaining QoS with new paths and potential power consumption increase).

To my opinion paper is good and can bring improvements in the subject area. Authors provided relevant introduction in the area and state of the art in related works emphasizing directions of power optimization from one side and QoS network monitoring strategies from another side. They clearly explained in details the problem and proposed solution, experimental part for validation and obtained results.

I advise to accept the paper. I provide several minor comments that can, to my opinion, improve the paper.

Comments

- Is it possible in Abstract and introduction to clearly state what is the main parameter for optimization, is it QoS or power consumption? Or it is a joint optimization of both parameters.

- All abbreviations should be defined on first appearance in the Abstract, and after that in same way in the paper. Authors should carefully check this. Example: Abstract – DCNs.

- Please check “This paper proposes a new framework that considers efficient power usage whilst ensuing an acceptable level of Quality of Service (QoS) is provided…”

- Please check “The primary objective of the Q-PoPS framework that is introduce ….”

- Please check Figure 9 and 12 for the size of text.

Author Response

Dear Reviewer,

We are writing to submit our response to your feedback. We highly appreciate the time and effort you dedicated to the review process, which was thorough and greatly contributed to improving our paper. Below, you will find our point-by-point response to your review comments.

Comment 1: Is it possible in Abstract and introduction to clearly state what is the main parameter for optimization, is it QoS or power consumption? Or it is a joint optimization of both parameters.

Response 1: In response to your valuable feedback, we have added a list of contributions to the end of the introduction section (from line 91 to 103).

Comment 2: All abbreviations should be defined on first appearance in the Abstract, and after that in same way in the paper. Authors should carefully check this. Example: Abstract – DCNs.

Response 2: In response to your insightful comment, we have updated the revised paper accordingly.

Comment 3: Please check “This paper proposes a new framework that considers efficient power usage whilst ensuing an acceptable level of Quality of Service (QoS) is provided…”

Response 3: In response to your valuable comments, we have updated the passage in the revised paper (from line 83 to 87).

Comment 4: Please check “The primary objective of the Q-PoPS framework that is introduce ….”

Response 4: In response to your comments, we have updated the passage in the revised paper (from line 87 to 91).

Comment 5: Please check Figure 9 and 12 for the size of text.

Response 5: In response to your comments, we have updated the revised paper accordingly.

 

Sincerely,
Authors

 

Reviewer 2 Report

Comments and Suggestions for Authors

1. The abstract requires clear definition of the current problem and the motivation behind the proposed solution. There are some abbreviations that require to be explained like DCN.  

2. In the introduction, list the contribution as bullet points

3. Sections, 3, 4 and 5 have many subsections with repetitive titles and some of these don't reflect the content. 

4. The figures and tables captions are too long. 

5. In general, the paper is hard to follow

6. Figure 1 is not ideal for representing SDN, this needs to be changed 

Comments on the Quality of English Language

Minor changes are required. 

Author Response

Dear Reviewer,

We are writing to submit our response to your feedback. We highly appreciate the time and effort you dedicated to the review process, which was thorough and greatly contributed to improving our paper. Below, you will find our point-by-point response to your review comments.

Comment 1: The abstract requires clear definition of the current problem and the motivation behind the proposed solution. There are some abbreviations that require to be explained like DCN. 

Response 1: We agree with the reviewer. In response to your valuable comment, we updated the abstract in the revised paper to include the problem, motivation, proposed solution, and main findings. Please find the updated version (from line 1 to 21).

Comment 2:  In the introduction, list the contribution as bullet points.

Response 2: In response to your valuable feedback, we have added a list of contributions to the end of the introduction section (from line 92 to 103).

Comment 3: Sections, 3, 4 and 5 have many subsections with repetitive titles and some of these don't reflect the content.

Response 3: We apologize for any confusion caused. In response, we have modified the names of most of the subsections and added a gentle introduction to Section 3 to clarify the meaning and goals of its subsections.

Comment 4: The figures and tables captions are too long. 

Response 4: The reason behind the lengthy captions is to provide a comprehensive explanation, as recent research trends emphasize detailed captions for figures to convey a complete idea when someone searches solely for the image. In response to your valuable feedback, we have revised the paper by making the captions shorter. The updated figures are 5, 6, 7, 9, 10, 12, and 13, and the updated tables are 3, 4, 5, and 6. The captions for figures 3, 4, 8, and 11 have been retained as they are essential for ensuring thorough understanding.

Comment 5: In general, the paper is hard to follow.

Response 5: Thank you for your feedback. We have incorporated the suggested modifications based on the reviewers' valuable notes. We hope that these revisions have made the paper more readable and easier to follow.

Comment 6: Figure 1 is not ideal for representing SDN, this needs to be changed. 

Response 6: Based on your comment and the feedback from the third reviewer, we have decided to remove Figure 1 from the paper.

 

Sincerely,
Authors

Reviewer 3 Report

Comments and Suggestions for Authors

All figures must be placed between separate paragraphs.

Keywords are not consistent with the work, need to be redone.

 

Figure titles are very long and should be shortened.

I recommend the authors to delete the figures taken from internet sources (Fig 1 and Fig 2)

The bibliography must be rechecked.

The conclusions must be detailed with an emphasis on the results obtained.All figures must be placed between separate paragraphs.

Keywords are not consistent with the work, need to be redone.

 

The authors say “Data Availability Statement: The software models generated and the tools used by this research will

be made available to the public on GitHub repositories [43]." but at [43] hey haven't uploaded anything now.The authors say “Data Availability Statement: The software models generated and the tools used by this research will be made available to the public on GitHub repositories [43]." but at [43] hey haven't uploaded anything now.

 

Comments on the Quality of English Language

can be verified.

 

Author Response

Dear Reviewer,

We are writing to submit our response to your feedback. We highly appreciate the time and effort you dedicated to the review process, which was thorough and greatly contributed to improving our paper. Below, you will find our point-by-point response to your review comments.

Comment 1: All figures must be placed between separate paragraphs.

Response 1: In response to your valuable comment, we have updated the paper accordingly.

Comment 2: Keywords are not consistent with the work, need to be redone.

Response 2: In response to your valuable feedback, we have updated the paper with the following keywords: Data Center Networks, Energy Efficiency, Quality of Service, Software-Defined Networking, Real-time Traffic, Power Optimization, and QoS-Aware Path Selection.

Comment 3: Figure titles are very long and should be shortened.

Response 3: The reason behind the lengthy captions is to provide a comprehensive explanation, as recent research trends emphasize detailed captions for figures to convey a complete idea when someone searches solely for the image. In response to your valuable feedback, we have revised the paper by making the captions shorter. The updated figures are 5, 6, 7, 9, 10, 12, and 13, and the updated tables are 3, 4, 5, and 6. The captions for figures 3, 4, 8, and 11 have been retained as they are essential for ensuring thorough understanding.

Comment 4: I recommend the authors to delete the figures taken from internet sources (Fig 1 and Fig 2)

Response 4: Based on your comment, we have decided to remove Figure 1 from the paper. However, we have retained the second figure as it reflects the motivation of our study. Thank you.

Comment 5: The bibliography must be rechecked.

Response 5: We have thoroughly reviewed the references and expanded our literature review by including three additional state-of-the-art references. This has broadened the scope of our bibliography to cover a wider area of the literature (from line 138 to line 161).

Comment 6: The conclusions must be detailed with an emphasis on the results obtained

Response 6:  In response to your comment, we have revised the conclusion section to provide a more detailed discussion of the results obtained from our study. (from line 697 to 722)

Comment 7:  The authors say “Data Availability Statement: The software models generated and the tools used by this research will be made available to the public on GitHub repositories [43]." but at [43] hey haven't uploaded anything now.

Response 7: Yes we agree, we mentioned that "The software models generated and the tools used by this research will be made available to the public on GitHub repositories"

Indeed, we plan to upload all our work, including the software models and tools used in this research, to the GitHub repositories mentioned [43], to make it easier for the network community to take advantage of our work. We aim to include a brief video demonstrating how to conduct the experiments in one of the cases. As soon as I have sufficient time available, I will ensure that everything is uploaded in the near future, as we did with several of our previous research projects.

 

Sincerely,
Authors

Reviewer 4 Report

Comments and Suggestions for Authors

The article "QoS-Aware Power-Optimized Path Selection for Data Center Networks (Q-PoPS)" addresses a highly relevant topic. The research is of a high standard, with a clear methodology and effective validation. The contribution of the research is clearly demonstrated and well interpreted.

Author Response

Dear Reviewer,

We highly appreciate the time and effort you dedicated to the review process. Thank you very much.

Sincerely,
Authors

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have responded to my comments and have made the necessary changes. I think the paper is ready for publication