CMSC858F: Network Design Foundation, Fall 2011


Instructor: Mohammad T. HajiAghayi


Latest Announcements and Assignments (Last updated 12/08/11)



·        Solution 3 to Assignment 3  

·        Assignment 3:  Due 11/22/11 at 5pm (see instructions for submission inside the assignment)

·        Solution 2 to Assignment 2  

·        Assignment 2:  Due 11/2/11 before the class (see instructions for submission inside the assignment)

·        Solution 1 to Assignment 1

·        Assignment 1: Due 10/12/11 before the class (see instructions for submission inside the assignment)

·        Please notice the new times and locations from September 14, 2011 

·        See the course agenda

·        First lecture on August 31, 2011.

·        Templates .tex .sty to scribe.


Course Description

Network Design or more generally networking with its many variants is one of the most active research areas in computer science involving researchers from System, Networks, Algorithm Design, Graph Theory, Discrete Optimization, Game Theory and Information Theory. Especially mathematical modeling of networks plays a vital role in the understanding of computer and communication networks and provides insights into questions such as allocation of network resources, analysis and effects of competitive and/or cooperative agents, Internet protocols, wireless network protocols, network dynamics, queuing systems, performance optimization, and network traffic and topology. These models shed light onto fundamental performance limits and trade-offs in practical scenarios. In addition, new problems in this area are constantly propounded by practitioners working in various aspects of network design such as construction, routing and staged deployment. Furthermore, many new design paradigms such as ATM, Ad hoc and Wireless networking add rich new flavors to existing problems. On the other hand, many of the key algorithmic challenges in the context of the internet, the largest network in the world, require considering the objectives and interests of the different participants involved.  These include problems ranging from pricing goods and resources, to improving search, to routing, and more generally to understanding how incentives of participants can be harnessed to improve the behavior of the overall system.  As a result, Mechanism Design and Algorithmic Game Theory, which can be viewed as ``incentive-aware algorithm design'', have become an increasingly important part of network design in recent years.


We focus on active area of applications of algorithms in networking to understand current trends, identify understudied areas, and potentially formulate new directions for further investigation. Below I highlight some of the main selection of topics and their corresponding references that we will cover in this course (we may add more references later to this list).

Reference Books:


Approximation Algorithms, by Vazirani, Springer, 2001
Algorithmic Game Theory, edited by Nisan, Roughgarden, Tardos, and Vazirani, Cambridge University Press, 2007.

Slides and notes from ``Approximation Algorithms: The Last Decade and the Next Workshop, June 2011''

Notes from the webpage of a similar course taught by the same instructor

Detailed Schedule (see the references below):


8/31/11: Review of course description, review of different approximation algorithms for set cover.

              My scanned handwritten notes

              Scribe notes by students      


09/07/11: Submodular cover, submodular tree coverage and maximum coverage with budget.

              My scanned handwritten notes

              Scribe notes by students


09/14/11: Continuing maximum coverage, unique coverage, and applications to wireless networks.

              My scanned handwritten notes:

              Scribe notes by students


09/19/11: Buy-at-bulk network design and a brief overview of the best prize-collecting Steiner tree algorithm.



09/21/11: Review of probabilistic embedding into trees for connectivity problems: definitions and applications.

              My scanned handwritten notes

              Scribe notes by students


09/23/11: Guest Lecture by Jaroslaw Byrka: Iterative randomized rounding for Steiner tree



09/28/11: Review of Bartal-FRT proof for probabilistic embedding into trees, also another application of this technique for network design

              My scanned handwritten notes

              Scribe notes by students


10/05/11: Guest Lecture by Marek Cygan: Review of algorithms for group Steiner tree, k-center and k-median

               Scribe notes by students


10/12/11: Review of oblivious routing algorithms

  Scanned handwritten notes

              Scribe notes by students


10/19/11: Probabilistic embedding into trees for cut problems: Racke from FRT

  Scanned handwritten notes

              Scribe notes by students


            10/26/11: Review of primal-dual algorithms for Steiner tree and Steiner forest, Prize-collecting versions, k-MST

              Scanned handwritten notes

              Scribe notes by students


11/02/11: Review of algorithms for facility location and connected facility location (single-sink rent-or-buy network design)

  Scanned handwritten notes

              Scribe notes by students


11/09/11: Approximation algorithms for planar networks



09/23/11: Guest Lecture by R. Ravi: Iterative methods in combinatorial optimizations



11/16/11:  Exam


11/23/11: Thanksgiving Holiday


11/30/11: Paper and project presentations by students.

                Graph Balancing Slides  Scribe notes

                On (In)Tractability of Movement Problems Slides Scribe notes


 12/07/11: Paper and project presentations by students (the last day of the class).

               Clearing Paths with Minimum Movement Slides  Scribe notes

               Vehicle Routing With Time-Windows Slides  Scribe notes


Tentative Course Topics and References:


Set cover, maximum coverage and unique coverage:

•           Above book Approximation Algorithms, by Vazirani, 2001.

•           The Budgeted Maximum Coverage Problem, Samir Khuller, Anna Moss, Joseph (Seffi) Naor, Information Processing Letters, 1997.

•           E.D. Demaine, U. Feige, M.T. Hajiaghayi;  M.R. Salavatipour; Combination can be hard: approximability of the unique coverage problem, SIAM Journal on Computing. A preliminary version appeared in the 17th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), Vancouver, Miami, Florida, January 22-24, 2006, pp. 162-171.


Technique of probabilistic embedding into trees:

•           Yair Bartal: Probabilistic Approximations of Metric Spaces and Its AlgorithmicApplications . FOCS 1996: 184-193

•           Jittat Fakcheroenphol, Kunal Talwar and Satish Rao, A tight bound on approximating arbitrary metrics by tree metrics

STOC 2003, J. Comput. Syst. Sci. 69(3): 485-497 (2004).

•           Michael Elkin, Yuval Emek, Daniel Spielman and Shang-Hua Teng, Lower-Stretch Spanning Trees, 37th ACM Symposium on Theory of Computing,  2005.


Planar Networks:

•           Brenda S. Baker, Approximation Algorithms for NP-Complete Problems on Planar Graphs. J. ACM 41(1): 153-180. (1994)

•           E.D. Demaine; M.T. Hajiaghayi; K Kawarabayashi; Algorithmic Graph Minor Theory: Decomposition, Approximation, and Coloring, In Proceedings of the 46th Annual IEEE Symposium on Foundations of Computer Science (FOCS), Pittsburgh, PA, October 23-25, 2005, pp.  637-646.

•           Philip N. Klein, A linear-time approximation scheme for TSP for planar weighted graphs, Proceedings, 46th IEEE Symposium on Foundations of Computer Science  (2005), pp. 647--656.

•           E.D. Demaine; M.T. Hajiaghayi; The Bidimensionality Theory and Its Algorithmic Applications,

A servey in Computer Journal, To appear.


Oblivious routing:

•           Harald Rδcke. Minimizing Congestion in General Networks. In Proc. of the 43rd FOCS, pp. 43-52, 2002.

•           Harrelson, Hildrum, and Rao, A polynomial-time tree decomposition to minimize congestion. SPAA 2003.

•           Yossi Azar, Edith Cohen, Amos Fiat, Haim Kaplan, and Harald Rδcke. Optimal Oblivious Routing in Polynomial Time. In Proc. of the 35th STOC, pp. 383-388, 2003.

•           A. Gupta; M.T. Hajiaghayi;  H. Raecke; Oblivious Network Design, In Proceedings of the 17th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), Vancouver,  Miami, Florida, January 22-24, 2006, pp. 970-979.


Cost sharing:

•           Anupam Gupta, Amit Kumar, Tim Roughgarden, Simpler and better approximation algorithms for network design. STOC 2003: 365-372

•           Anupam Gupta, Amit Kumar, Martin Pαl and Tim Roughgarden Approximation Via Cost-Sharing: A Simple Approximation Algorithm for the Multicommodity Rent-or-Buy Problem. J. ACM, 54(3), March 2007

•           Jain and Mahdian, Cost Sharing, in Algorithmic Game Theory book above.


Buy-at-bulk network design:

•           Adam Meyerson, Kamesh Munagala, and Serge Plotkin: Cost-Distance: Two-Metric Network Design. IEEE Symposium on Foundations of Computer Science (FOCS) 2000.

•           Adam Meyerson. Online Facility Location. FOCS 2001.

•           Sudipto Guha, Adam Meyerson, and Kamesh Munagala: Hierarchical Placement and Network Design Problems. IEEE Symposium on Foundations of Computer Science (FOCS) 2000.  

•           David B. Shmoys, Ιva Tardos, Karen Aardal: Approximation Algorithms for Facility Location Problems. STOC 1997: 265-274

•           C. Chekuri; S. Khanna; S. Naor:  A deterministic algorithm for the cost-distance problem. SODA 2001: 232-233.

•           C. Chekuri; M.T. Hajiaghayi; G. Kortsarz; M. R. Salavatipour:  Approximation algorithms for node–weighted  buy-at-bulk networks, In  Proceedings of  the 18th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA),  New Orleans, LA, January 7-9, 2007, pp. 1265--1274.

•           C. Chekuri; M.T. Hajiaghayi; G. Kortsarz; M. R. Salavatipour:   Approximation algorithms for non-uniform buy-at-bulk network design problems  In Proceedings of the 47th Annual IEEE Symposium on Foundations of Computer Science (FOCS), Berkeley, PA, October 22-24, 2006, pp. 677—686.


Price of anarchy and selfish routing:

•           T. Roughgarden, The Price of Anarchy Is Independent of the Network Topology, Journal of Computer and System Sciences, 67(2):341--364, 2003. (Conference version in STOC 2002.)

•           E. Tardos, lecture notes from Cornell CS684.

•           J. R. Correa, N. E. Stier Moses, and A. S. Schulz, Selfish Routing in Capacitated Networks, Mathematics of Operations Research, 2004 (to appear).

•           J. R. Correa, N. E. Stier Moses, and A. S. Schulz, A geometric approach to the price of anarchy in nonatomic congestion games, Games and Economic of Behavior, to appear, 2008.

•           T. Roughgarden and E. Tardos, How Bad Is Selfish Routing?, Journal of the ACM, 49(2):236--259, 2002.


Network creation and formation games:

•           E. Tardos and T. Wexler, Network Formation Games, in Algorithmic Game Theory book above.

•           Alex Fabrikant, Ankur Luthra, Elitza N. Maneva, Christos H. Papadimitriou, Scott Shenker: On a network creation game. PODC 2003: 347-351.

•           E.D. Demaine; M.T. Hajiaghayi; H. Mahini; M. Zadimoghadam; The price of anarchy in network creation games, In Proceedings of the 26th Annual ACM Symposium on Principles of Distributed Computing (PODC), Portland, Oregon, August 2007, pages 292—298.


Online mechanism design:

•           D. Parkes, On-line Mechanisms, in Algorithmic Game Theory book above.

•           M.T. Hajiaghayi; R.D. Kleinberg; M. Mahdian; D.C. Parkes; Online Auctions with Re-usable Goods, In Proceedings of the 6th ACM Conference on Electronic Commerce (EC), pp. 165-174, Vancouver, Canada, June 5-8, 2005.

•           Hajiaghayi, M.T.; Kleinberg, R.; Parkes, D.C.;  Adaptive Limited-Supply Online Auctions, Proc. ACM Conference on Electronic Commerce (EC), pp. 71-80, May 17-20, 2004. New York.


Profit maximization auctions:

•           Jason Hartline, Anna Karlin, Profit Maximization in Mechanism Design, in Algorithmic Game Theory book above.

•           Andrew Goldberg, Jason Hartline, Anna Karlin, Mike Saks, and Andrew Wright, Competitive Auctions, Games and Economic Behavior, 2006.

•           Venkatesan Guruswami, Jason D. Hartline, Anna R. Karlin, David Kempe, Claire Kenyon, Frank McSherry: On profit-maximizing envy-free pricing, SODA 2005: 1164-1173.


Wireless network design:

•           M.T. Hajiaghayi; N. Immorlica; V.S. Mirrokni; Power Optimization in Fault-Tolerant Topology Control Algorithms for Wireless Multi-hop Networks, IEEE/ACM Transactions on Networking. To appear. A preliminary version appeared in the Ninth Annual International Conference on Mobile Computing and Networking (MOBICOM), San Diego, CA,  September 15-18 2003, pp. 300-312.

•           M.T. Hajiahgayi; G. Kortsarz; V. S. Mirrokni; Z. Nutov; Power Optimization for Connectivity Problems, A Mathematical Programming, Series B for selected papers from IPCO 2005. Vol 110, No 1, pp. 195--208, 2007.

•           Goemans, Li, Mirrokni and Thottan, Market Sharing games applied to Content Distribution in Ad-Hoc Networks , MobiHoc 2004.

•           J.L. Bredin; E.D. Demaine; M.T. Hajiaghayi; D. Rus; Deploying Sensor Nets with Guaranteed Capacity and Fault Tolerance, In Proceedings of the 6th ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc),  Urbana-Champaign, IL, May 2005,  pp. 309--319.




A basic course in algorithms is required. Already passing an advanced course in algorithms or networking can be quite helpful. If you are unsure of whether you have sufficient background for this course or not, please contact the instructor in the first week of the class or before.


Tentative Grading & Evaluation


Each student will be expected to scribe 1-2 lectures (10%) and participate in class discussions (10%). There will be three homeworks (5% each), one exam (20%), a paper presentation in the class (15%) and a (possibly collaborative) project and its brief presentation in the class (30%). A very strong project can potentially compensate the low grades in other parts.  Details about the project and ideas will be given in the second week of the class, though the general ideas can be seen from the course topics.


            Other Resources (from here)


            Tips for good technical writing

•           The elements of style by William Strunk Jr. and E. B. White (follow the "External links" at the bottom of this page for online copies of this book).

•           Writing a technical paper, by Professor Michael Ernst.

      •           Tips for writing technical papers, by Professor Jennifer Widom.

•           Writing suggestions, by Professor Barton Miller.

•           How to write a dissertation, by Professor Douglas Comer (most of the content on this page applies to all forms of technical writing).


            Tips for effective presentation

•           Giving a technical talk, by Professor Michael Ernst.

•           Tips for a good conference talk, by Professor Jennifer Widom.

•           Oral presentation advice, by Professor Mark Hill.


General Information


Mohammad T. HajiAghayi

Time and Location:

Wednesdays from 1pm to 1:55pm at A.V. Williams 3258 and Wednesdays from 4pm-5:35pm at CSI 3118

Office hours:      

By appointment via e-mail OR the hour immediately following class.


3249 A.V. Williams




The first 8 letters of instructor’s last name (AT) cs (DOT) umd (DOT)  edu