Comparison-Based FIFO Buffer Management in QoS Switches

  • Kamal Al-BawaniEmail author
  • Matthias Englert
  • Matthias Westermann
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9644)


The following online problem arises in network devices, e.g., switches, with quality of service (QoS) guarantees. In each time step, an arbitrary number of packets arrive at a single FIFO buffer and only one packet can be transmitted. Packets may be kept in the buffer of limited size and, due to the FIFO property, the sequence of transmitted packets has to be a subsequence of the arriving packets. The differentiated service concept is implemented by attributing each packet with a non-negative value corresponding to its service level. A buffer management algorithm can reject arriving packets and preempt buffered packets. The goal is to maximize the total value of transmitted packets.para We study comparison-based buffer management algorithms, i.e., algorithms that make their decisions based solely on the relative order between packet values with no regard to the actual values. This kind of algorithms proves to be robust in the realm of QoS switches. Kesselman et al. [13] present a comparison-based algorithm that is 2-competitive. For a long time, it has been an open problem whether a comparison-based algorithm exists with a competitive ratio below 2. We present a lower bound of \(1+1/\sqrt{2} \approx 1.707\) on the competitive ratio of any deterministic comparison-based algorithm and give an algorithm that matches this lower bound in the case of monotonic sequences, i.e., packets arrive in a non-decreasing order according to their values.


Online algorithms Competitive analysis Network switches Buffer management Quality of service Comparison-based 


  1. 1.
    Aiello, W., Mansour, Y., Rajagopolan, S., Rosén, A.: Competitive queue policies for differentiated services. J. Algorithms 55(2), 113–141 (2005)MathSciNetCrossRefzbMATHGoogle Scholar
  2. 2.
    Andelman, N., Mansour, Y.: Competitive management of non-preemptive queues with multiple values. In: Fich, F.E. (ed.) DISC 2003. LNCS, vol. 2848, pp. 166–180. Springer, Heidelberg (2003)CrossRefGoogle Scholar
  3. 3.
    Andelma, N., Mansour, Y., Zhu, A.: Competitive queueing policies for QoS switches. In: Proceedings of the 14th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), pp. 761–770 (2003)Google Scholar
  4. 4.
    Andelman, N.: Randomized queue management for DiffServ. In: Proceedings of the 17th ACM Symposium on Parallelism in Algorithms and Architectures (SPAA), pp. 1–10 (2005)Google Scholar
  5. 5.
    Azar, Y., Cohen, I.R.: Serving in the dark should be done non-uniformly. In: Halldórsson, M.M., Iwama, K., Kobayashi, N., Speckmann, B. (eds.) ICALP 2015. LNCS, vol. 9134, pp. 91–102. Springer, Heidelberg (2015)Google Scholar
  6. 6.
    Azar,Y., Cohen, IR., Gamzu, I.: The loss of serving in the dark. In: Proceedings of the 45th ACM Symposium on Theory of Computing (STOC), pp. 951–960 (2013)Google Scholar
  7. 7.
    Azar, Y., Richter, Y.: The zero-one principle for switching networks. In: Proceedings of the 36th ACM Symposium on Theory of Computing (STOC), pp. 64–71 (2004)Google Scholar
  8. 8.
    Bansal, N., Fleischer, L.K., Kimbrel, T., Mahdian, M., Schieber, B., Sviridenko, M.I.: Further improvements in competitive guarantees for QoS buffering. In: Díaz, J., Karhumäki, J., Lepistö, A., Sannella, D. (eds.) ICALP 2004. LNCS, vol. 3142, pp. 196–207. Springer, Heidelberg (2004)CrossRefGoogle Scholar
  9. 9.
    Englert, M., Westermann, M.: Considering suppressed packets improves buffer management in QoS switches. In: Proceedings of the 18th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), pp. 209–218 (2007)Google Scholar
  10. 10.
    Englert, M., Westermann, M.: Lower and upper bounds on FIFO buffer management in QoS switches. Algorithmica 53(4), 523–548 (2009)MathSciNetCrossRefzbMATHGoogle Scholar
  11. 11.
    Goldwasser, M.H.: A survey of buffer management policies for packet switches. SIGACT News 41, 100–128 (2010)CrossRefGoogle Scholar
  12. 12.
    Kesselman, A., Mansour, Y., Van Stee, R.: Improved competitive guarantees for QoS buffering. Algorithmica 43(1–2), 97–111 (2005)MathSciNetCrossRefzbMATHGoogle Scholar
  13. 13.
    Kesselman, A., Lotker, Z., Mansour, Y., Patt-Shamir, B., Schieber, B., Sviridenko, M.: Buffer overflow management in QoS switches. SIAM J. Comput. 33(3), 563–583 (2004)MathSciNetCrossRefzbMATHGoogle Scholar
  14. 14.
    Li, F., Sethuraman, J., Stein, C.: Better online buffer management. In: Proceedings of the 18th Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), pp. 199–208 (2007)Google Scholar
  15. 15.
    Paxson, V., Floyd, S.: Wide-area traffic: the failure of Poisson modeling. IEEE/ACM Trans. Networking 3(3), 226–244 (1995)CrossRefGoogle Scholar
  16. 16.
    Sleator, D., Tarjan, R.: Amortized efficiency of list update and paging rules. Commun. ACM 28(2), 202–208 (1985)MathSciNetCrossRefGoogle Scholar
  17. 17.
    Veres, A., Boda, M.: The chaotic nature of TCP congestion control. In: Proceedings of IEEE INFOCOM, pp. 1715–1723 (2000)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Kamal Al-Bawani
    • 1
    Email author
  • Matthias Englert
    • 2
  • Matthias Westermann
    • 3
  1. 1.Department of Computer ScienceRWTH Aachen UniversityAachenGermany
  2. 2.DIMAP and Department of Computer ScienceUniversity of WarwickCoventryUK
  3. 3.Department of Computer ScienceTU DortmundDortmundGermany

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