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Aggressiveness Protective Fair Queuing for Bursty Applications

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Presentation on theme: "Aggressiveness Protective Fair Queuing for Bursty Applications"— Presentation transcript:

1 Aggressiveness Protective Fair Queuing for Bursty Applications
Nir Halachmi (IDC) Joint work with Dr. Anat Bremler Barr (IDC) and Prof. Hanoch Levy (TAU) APFQ - Nir Halachmi (IDC)

2 Background: Network planning
Network Designers use the traffic properties to plan the capacity of the network. Link Capacity APFQ - Nir Halachmi (IDC)

3 Background: Exploiters
Malicious: Denial of Service (DDOS) Innocent: pre-fetching, massive users Drop Link Capacity Exploiter APFQ - Nir Halachmi (IDC)

4 Background: Solution- Fair Scheduling protection against Exploiters
Weighted Fair Queuing (WFQ) mechanisms provides that the resource is fairly (typically equally) divided among all Drop 1 Link Capacity 1 Exploiter Drop APFQ - Nir Halachmi (IDC)

5 APFQ - Nir Halachmi (IDC)
Our main contribution The user traffic is bursty. WFQ cannot provide fair service to bursty applications in the presence of aggressive users We propose WFQ-like mechanism called Aggressiveness Protective Fair Queuing (APFQ) that solves this problem. APFQ - Nir Halachmi (IDC)

6 APFQ - Nir Halachmi (IDC)
Bursty Application Many application are bursty (model on/off ~ active/idle) Http on off on off Time APFQ - Nir Halachmi (IDC)

7 APFQ - Nir Halachmi (IDC)
Bursty Traffic Network Designers use the traffic burstiness property to plan the capacity of the network. Drop Link Capacity Drop APFQ - Nir Halachmi (IDC)

8 APFQ - Nir Halachmi (IDC)
Aggressive Users Aggressive user use the idle time to get more BW Drop Link Capacity Drop APFQ - Nir Halachmi (IDC)

9 APFQ - Nir Halachmi (IDC)
WFQ defensives WFQ cannot provide good fairness in the presence of such aggressive users. Drop Link Capacity Drop APFQ - Nir Halachmi (IDC)

10 The effect of aggressive user on polite users (WFQ)
APFQ - Nir Halachmi (IDC)

11 Aggressiveness Protective Fair Queuing (APFQ)
We propose a new WFQ-like mechanism called Aggressiveness Protective Fair Queuing (APFQ) that solves this problem by dynamically decreasing the weight of the aggressive users. APFQ - Nir Halachmi (IDC)

12 APFQ - Nir Halachmi (IDC)
Agenda Related Work. Solution Requirements. APFQ algorithm. APFQ analysis Simulation. APFQ - Nir Halachmi (IDC)

13 APFQ - Nir Halachmi (IDC)
Related Work Dynamic WFQ was proposed to handle the fact that it is hard to assign static weight accurately [Shin and el. 2001][Makrakis and el. 2001]. Fix the weight according to arrival rate or the queue length. Does not address bursty traffic problem. Dynamic WFQ was proposed as part of a mechanism to handle DDOS [Thomas and el. 2003] Penalty mechanism to flows Does not deal with traffic burstiness and does not suggest or analyze the weight function mechanism APFQ - Nir Halachmi (IDC)

14 Solution Requirements
Provide fairness to polite users. The limitation imposed on the users is a function of the system load. Protect innocent users by negatively discriminating aggressive users on an overloaded Network. Drop Link Capacity Drop APFQ - Nir Halachmi (IDC)

15 APFQ - Nir Halachmi (IDC)
Dynamic weight function that reduces the weight assigned to aggressive users For every flow (user) the mechanism counts the amount of traffic that a source has generated in the near history It uses this amount to affect the weight given to the user. APFQ - Nir Halachmi (IDC)

16 APFQ - Nir Halachmi (IDC)
Weight function BS – the assigned quota. SM(t) – offered traffic during the last sliding. window in time t. wo original fix weight. α – punishment factor – configure by the system. APFQ - Nir Halachmi (IDC)

17 APFQ - Nir Halachmi (IDC)
APFQ Illustrated Polite user transmit data: Time Aggressive User Transmitted data under WFQ Aggressive User Transmitted data under APFQ APFQ - Nir Halachmi (IDC)

18 APFQ - Nir Halachmi (IDC)
APFQ algorithm KBytes 1 7 Time W(0) Weight APFQ - Nir Halachmi (IDC) Time

19 Analysis pre conditions
Polite user transmits at rate R for Ton and idle for Toff. Aggressive user transmits at constant peak rate R. N concurrently active users. K aggressive users , N-K polite users. For each user original fix weight wo = 1 Packets that are not transmitted within a period of ∆ from their arrival time are dropped. B is the output link capacity. ∆ = Ton + Toff = sliding window size. ƒ = burst factor = APFQ - Nir Halachmi (IDC)

20 APFQ - Nir Halachmi (IDC)
Polite User Offered Data Transmitted Data WFQ Transmitted Data APFQ APFQ - Nir Halachmi (IDC)

21 APFQ - Nir Halachmi (IDC)
Naive Aggressive User Offered Data Total offered Data Transmitted Data WFQ APFQ - Nir Halachmi (IDC)

22 APFQ - Nir Halachmi (IDC)
Naive Aggressive User Transmitted Data APFQ For α =1 For α=2 APFQ - Nir Halachmi (IDC)

23 Continuous Naive Aggressive
Continuous Naive Aggressive - an aggressive user that was active in the previous window size. I.e., offered traffic during the last sliding Hence the assigned weight is fixed APFQ - Nir Halachmi (IDC)

24 Continuous Naive Aggressive
Transmitted Data APFQ For α =1 Exactly as polite use under APFQ For α=2 Exactly as polite use under APFQ APFQ - Nir Halachmi (IDC)

25 Sophisticated Aggressive
Sophisticated Aggressive user is assumed to know the function used by APFQ and optimizes its offered traffic in order to maximize the traffic APFQ will transmit for him. Sophisticated Aggressive Sophisticated Aggressive user is assumed to know the function used by APFQ and optimizes its offered traffic in order to maximize the traffic APFQ will transmit for him. An approach for the sophisticated aggressive user is to offer the same amount of traffic as the mechanism allow her to transmit. APFQ - Nir Halachmi (IDC)

26 Sophisticated User Upper Bound
Lemma: Under APFQ a sophisticated aggressive user cannot transmit in a period of duration ∆ more than (m+2)·BS traffic where m is derived from equation APFQ - Nir Halachmi (IDC)

27 APFQ - Nir Halachmi (IDC)
Sketch of proof APFQ - Nir Halachmi (IDC)

28 Sophisticated User Lower Bound
Lemma: There is a strategy where the sophisticated aggressive user can transmit during an interval of length ∆ under APFQ with α at least (m+1)·BS traffic where m is derived from equation . APFQ - Nir Halachmi (IDC)

29 Optimal Strategy for sophisticated aggressive
APFQ - Nir Halachmi (IDC)

30 APFQ - Nir Halachmi (IDC)
Analysis Summery APFQ transmitted traffic (α=2) APFQ transmitted traffic (α=1) WFQ transmitted traffic User Type 1 Polite user 2 1 + log ƒ ƒ Naïve aggressive user Continuous naïve aggressive user Sophisticated user APFQ - Nir Halachmi (IDC)

31 APFQ - Nir Halachmi (IDC)
Simulation Simulated APFQ on NS2 NS2 code implementing WFQ contributed by Paulo Losi APFQ was implemented as a software wrapper around WFQ. APFQ - Nir Halachmi (IDC)

32 APFQ - Nir Halachmi (IDC)
Tests Set-up APFQ - Nir Halachmi (IDC)

33 APFQ - Nir Halachmi (IDC)
Experiment 1 Examine the percentage of packets transmitted per flow as a function of the link capacity. Scenario 1: 12 polite users Scenario 2: 10 polite users and 2 aggressive users. APFQ - Nir Halachmi (IDC)

34 APFQ - Nir Halachmi (IDC)
Experiment 1 Results APFQ - Nir Halachmi (IDC)

35 APFQ - Nir Halachmi (IDC)
Experiment 2 Examine how many aggressive users a given network can handle without negatively affecting the polite users. Test APFQ robustness to large networks. APFQ - Nir Halachmi (IDC)

36 APFQ - Nir Halachmi (IDC)
Experiment 2 300 users with a variable number of aggressive users out of them. The number of aggressive users was increased in each round. The Link-capacity was set to 9000Kb/sec. APFQ - Nir Halachmi (IDC)

37 APFQ - Nir Halachmi (IDC)
Experiment 2 Results APFQ - Nir Halachmi (IDC)

38 Implementation consideration
APFQ can use a regular WFQ. Experiments revealed that Dynamic WFQ, in some scenarios, can causes disorder. The cause of the problem is that the WFQ implementation implicitly assumed the weight of the queues is constant (i.e. static weight). APFQ - Nir Halachmi (IDC)

39 APFQ - Nir Halachmi (IDC)
Conclusion Aggressive users use the idle time to get more bandwidth. WFQ has a fairness problems in the presence of aggressive users. APFQ is a mechanism that provide fairness in such cases, using a dynamic weight function. APFQ - Nir Halachmi (IDC)

40 APFQ - Nir Halachmi (IDC)
Questions ? Thank You APFQ - Nir Halachmi (IDC)

41 Problem demonstration
V_t =0 Time 1 1 P4 F=4 P3 F=3 P2 F=2 P1 F=1 V_t =1 Time 1 P1 F=1 1 P5 F=5 P4 F=4 P3 F=3 P2 F=2 V_t =2 Time 1 P2 F=2 P1 F=1 0.25 APFQ - Nir Halachmi (IDC) P6 F=9 P5 F=5 P4 F=4 P3 F=3

42 Problem demonstration
V_t =8.4 Time 1 P7 F=6 P5 F=5 P4 F=4 P3 F=3 P2 F=2 P1 F=1 0.25 P8 F=13 p6 F=9 V_t =9.2 Time 1 p6 F=9 P7 F=6 P5 F=5 P4 F=4 P3 F=3 P2 F=2 P1 F=1 0.25 P8 F=13 V_t =10 Time 1 P8 F=13 p6 F=9 P7 F=6 P5 F=5 P4 F=4 P3 F=3 P2 F=2 P1 F=1 0.25 APFQ - Nir Halachmi (IDC)

43 Problem demonstration
V_t =6 The new flow arrive and it’s finish time is set by the virtual time and not by the real round time (it finish time should have been 3) Time P7 F=6 P3 F=3 P2 F=2 P1 F=1 1 P8 F=13 p6 F=9 P5 F=5 P4 F=4 0.25 V_t =6.8 Time P7 F=6 P4 F=4 P3 F=3 P2 F=2 P1 F=1 1 P8 F=13 p6 F=9 P5 F=5 0.25 The new flow packet should have been transmitted by now V_t =7.6 Time P7 F=6 P5 F=5 P4 F=4 P3 F=3 P2 F=2 P1 F=1 1 P8 F=13 p6 F=9 0.25 APFQ - Nir Halachmi (IDC)

44 APFQ - Nir Halachmi (IDC)
Sketch of proof APFQ - Nir Halachmi (IDC)


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