Review Reports

Round 1

Reviewer 1 Report

In the paper, a new analytical model of a queuing system  to which a mixture of multi-service traffic is offered is proposed.

The most important notions related to the paper such as queuing system, QoS,  5G, etc. are briefly mentioned. Overall, the Introduction is well-written but the authors must include a paragraph explaining the importance of the studied queuing system for the QoS (and QoE) in overall telecommunication systems (including 5G and next generations). There are recent important and relevant studies on queuing systems which have not been mentioned by the authors. For example, in the paper:

Andonov, V. et al. (2019). A Queue in Overall Telecommunication System with Quality of Service Guarantees. In: Poulkov, V. (eds) Future Access Enablers for Ubiquitous and Intelligent Infrastructures. FABULOUS 2019. Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, vol 283. Springer, Cham.

a queuing system with FIFO discipline of service of the requests in overall telecommunication system with QoS guarantees is studied. Important parameters such as mean service time of a request, length of the queue, etc. are expressed.  Also, based on this, an analytical model of overall telecommunication system with queuing has been derived.

The analytical model derived by the authors is correct as demonstrated by the numerical results but the authors should address some questions. First, is the telecommunication system in a stationary state? This has not been mentioned anywhere! Second, when deriving expressions of a queuing system two cases must be discussed: mean service time of the requests with waiting (when the buffer has reached its capacity) and mean service time of the requests without waiting, see for more details:

Vishnevskiy, V.M.: Theoretical Foundations Of Computer Networks Planning. Tehnosfera, Moscow (2003).

In the Conclusion, I recommend to the authors to mention that the queuing system parameters can be used as QoS indicators or to define new QoS indicators of the telecommunication system.

 I recommend that the paper be published once the authors revise the paper according to my remarks above.

Minor editting is required.

Author Response

We are grateful to the reviewer for his kind comments that significantly improved the quality of our work. Thanks to his suggestions as to how papers might be improved we had a chance to clarify specific details with regard to the content of the paper and correct the typos. We have extensively revised our manuscript according to the reviewers’ recommendations to improve the quality of the paper. All answers are included in attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

Essentially, the authors have considered the finite capacity multi-server queueing system with three types of users, streaming, flexible and adaptive with possibility of queueing.  Model is useful from the point of view of potential applications. Approximate analysis of the model is provided. Numerical illustrations are presented. Results continue a collection of models previously analysed by authors. Results look correct. The minimal editorial correction to be done are as follows.  Page 5. Values $n_s$ and $n_c$ are defined only after they used. Phrase in lines 143-144 has to be corrected. Parameters like $\lambda_{s,i}$ on page 3 contain index $i$ meaning of which is explained only on page 5.

Author Response

We are grateful to the reviewer for his kind comments that significantly improved the quality of our work. Thanks to his suggestions as to how papers might be improved we had a chance to clarify specific details with regard to the content of the paper and correct the typos. We have extensively revised our manuscript according to the reviewers’ recommendations to improve the quality of the paper. All answers are included in attached file.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I would like to thank the authors for taking into account my remarks. The paper has been improved. I recommend that the paper be published in the present form.

Minor editting is required. 

Author Response

Thank you for your remark.
The article was thoroughly read. We have corrected the language errors found.