# Student seminar instructions

The length of the presentation should be ca. 15 minutes per student. If you are more students presenting, you should share the presentation more or less equally. For the presentation you can use my laptop, you can forward me the slides before the lectures if you prefer. Prepare a presentation that the other are able to follow.

New: When you present a paper, start with giving a general picture of the paper, discussing:
- What is the problem the papers deals with,
- Why is this problem interesting,
- How does the paper deal with this problem.

### 1. Traffic models

A. Adas, “Traffic models in Broadband Networks”, IEEE Communications Magazine, July 1997, parts on markovian traffic models, and references 4 Sections I,II,III, and V. (pdf)

Discuss the MMPP and the MM fluid models.
Auto-correlation function
Explain how to estimate the parameters of the models from measured data.
Discuss (not derive!) the performance parameters of queues with markov modulated arrival process.

### 2. Congestion and error control. TCP

J. Padhye, F. Firoiu, D. Towsley, J. Kurose, "Modeling TCP throughput: a simple model and its empirical validation," Sigcomm, 1998. Read sections 1, 2-2.1, 3, 4, 5.

Introduce the problem the paper addresses. Explain "what", "why, "how".

• Explain briefly how TCP Reno works (including slow start, fast retransmit, etc.)

• List and explain the assumptions used in model 2.1 – why are these assumptions necessary and how are they valid? How does the model differ from the one presented on the lecture?

• Explain the analysis in 2.1 and related performance figures from section 4

### 3. Scheduling

Both of the presentations on lecture 6!

Carlos, Ji: A. Parekh, R. Gallager, “A Generalized Processor Sharing Approach to Flow Control - The Single Node Case,” IEEE Transaction on Networking, 1993, Vol.1, No.3.

Read I-III-before part A, check V,VI,VIII
Summarize GPS, PGPS, Discuss Figs. 1,2 and Table 1, prove the main results in III (before part A)
Babak, Maykel, Hassan: H. Zhang, “Service Disciplines for Guaranteed Performance Service in Packet-Switching Networks,” Proceedings of the IEEE, Oct, 1995, pp. 1374-1396

Read sections I and II, III.A,B,G, IV.A,B,C,G
Explain how the guaranteed service works, what are its performance parameters and the traffic models used.
Explain what work conserving service discipline is, and present the virtual clock, WFQ and WF2Q mechanisms. (use figs. 3,4)
Explain what nonwork-conserving service discipline is and present the Jitter-EED, Stop-and-go and Hierarchical Round Robin mechanisms. (use figs. 10,13)

### 4. Fairness

L. Massoulie, J. Roberts, "Bandwidth sharing: objectives and algorithms,“ IEEE Infocom 2000 (Sections I and II)

Introduce briefly the problematic of fairness and distributed fairness control.
Explain the different fairness definitions in section II and show with a numerical example how they work on the parking lot scenario. Compare their performance in terms of throughput on long and short routes and overall throughput.

### 5. Multimedia - delay control

[1] N. Laoutaris, I. Stavrakakis, “Adaptive playout strategies for packet video receivers with finite buffer capacity,” IEEE ICC 2001.
[2] M. Yuang, Y.G. Chen, C.L. Shen, “Dynamic playout smoothing method for multimedia applications,” IEEE ICC, 1996. (main reference in [1])

Present [1] I-IV. Make sure you explain the Markov-chain describing the system clearly. Give the state transition probability matrix and diagram for the case of Poisson arrivals (detailed in [2]).

Also, Athanasios presents home assignment 5.1. on the simple playout buffer model.

### 6. Multimedia - loss control

Paper: X. Yu, J.W. Modestino, X. Tian, “The accuracy of Gilbert models in predicting packet-loss statistics for a single multiplexer network model,” IEEE Infocom, 2005
read: I-IV, VI (can skip III.D.)

Presentation: I-IV, parts of VI. These are the parts on loss process analysis, without the specific application of FEC. Discuss the analytical results and also the numerical examples (Some of the figures 6-12). Use also the part of the conclusion that is not related to FEC.