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1 Rate and distance fairness in OBS networks Tananun Orawiwattanakul, Yusheng Ji.

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Presentation on theme: "1 Rate and distance fairness in OBS networks Tananun Orawiwattanakul, Yusheng Ji."— Presentation transcript:

1 1 Rate and distance fairness in OBS networks Tananun Orawiwattanakul, Yusheng Ji

2 2 Topics Optical Burst Switching (OBS) Networks Rate and Distance Fairness Preemption (RDFP) Simulation results Future works

3 3 First OBS commercial product (2006) Matisse Networks' EtherBurst is the world's first optical burst switch, purpose-build for scaling metro and campus networks from 10 to 640 gigabits-per-second (Gbps).

4 4 Optical Burst Switching (OBS)

5 5 DB4 Data Channels DB1 DB3 DB2 Time Control Channels C1C2 C3 C4 T1T2T3T4T5 Offset Time1 Offset Time4 Offset Time1 Offset Time3 Offset Time2 C5 DB5 Offset Time5 No Buffer -> High Losses Void ->Network cannot be fully utilized Challenge of OBS DB C Data Burst Burst Control Packet

6 6 Rate Fairness Rate fairness refers to the fair bandwidth allocation (FBA) for each connection according to its offered rate and available bandwidth in the network. The fair rate of flow 1 and flow 2 is 5 Gbps. Its NOT FAIR!!! for me.

7 7 Distance fairness S4S4 S5S5 S3S3 S1S1 S6S6 S7S7 S8S8 S2S2 Path of Flow 1 Path of Flow 2 Distance fairness refers to the fair performance in terms of loss which respects to hop counts between the source and destination. The loss probability of long- path flow tends to be higher than that of short path flow. Its NOT FAIR!!! for me.

8 8 Rate and Distance Fairness Preemption (RDFP) Provide both Rate and Distance fairness in OBS networks.

9 9 Rate and Distance Fairness Preemption (RDFP) 1.Allocate bandwidth to each flow according to the max-min fairness. 2.If any of the connections send the input traffic higher than their optimum fairly allocated bandwidth, the RDFP scheme can protect and prevent well-behaved connections from being degraded by misbehavior of other flows (rate fairness). 3.In the meantime, RDFP also balances the loss probability of bursts with different number of hops between the source and destination (distance fairness) for transmitted traffic amounts under the max-min rate.

10 10 Ingress Edge Switch Egress Edge Switch Core Switch 1 Core Switch 2 Core Switch N Flow id Original Arrival Rate Optimal Fairly Allocated Bandwidth iAiTi RDFP: Control Plane FBCP AiAi BBCP TiTi

11 11 Rate Fairness Preemption (RFP) RDFP: Burst Marking Time Input Rate Ingress Edge Switch Flow id Original Arrival Rate Optimal Fairly Allocated Bandwidth iAiTi when Ai Ti, all bursts are marked as Under-rate bursts (HIGH PRIORITY) TiTi AiAi Under-rate bursts (HIGH PRIORITY)

12 12 Rate Fairness Preemption (RFP) RDFP: Burst Marking Time Input Rate Ingress Edge Switch Flow id Original Arrival Rate Optimal Fairly Allocated Bandwidth iAiTi TiTi AiAi when Ai > Ti bursts are marked as Over-rate bursts (LOW PRIORITY) with probability Pi-O = (Ai – Ti)/ Ai Unver-rate bursts (HIGH PRIORITY) with probability Pi-U = 1- Pi-O Over-rate bursts (LOW PRIORITY) Under-rate bursts (HIGH PRIORITY)

13 13 When contention occurs in core networks, the Under-rate (HIGH PRIORITY) bursts can preempt an original scheduled channel from Over-rate (LOW PRIORITY) bursts with different flow ids. DB4 Data Channels DB3 DB2 Time Control Channels C2 C3 C4 T2T3T4T5 Offset Time1 C5 DB5 Offset Time5 Under-rate Burst DB5 DB1 C1 T1 Offset Time1 Over-rate Burst RDFP: Rate fairness preemption policy If no original scheduled over-rate burst -> determine the DISTANCE FAIRNESS preemption policy.

14 14 When contention occurs in core networks, the Under-rate (HIGH PRIORITY) bursts can preempt an original scheduled channel from bursts with lower of I. DB4 Data Channels DB3 DB2 Time Control Channels C2 C3 C4 T2T3T4T5 Offset Time1 C5 DB5 Offset Time5 Under-rate Burst DB5 DB1 C1 T1 Offset Time1 Under-rate Burst with Lower I RDFP: Distance fairness preemption policy I = No of sucessful hops – Weight * (No. of remaining hops)

15 15 Simulation networks The network consists of 42 flows: 3-hop flows = 14 flows, 4-hop flows = 14 flows, and 5-hop flows = 15 flows. No. of data wavelength = 16

16 16 RDFP: simulation results Normalized rate 1 = 16 Gbps. Input rate of each 3-hop and 4-hop flow = Input rate of each 5-hop =

17 17 Future works Extensively study the performance of TCP in RDFP-OBS based network.

18 18 Q & A Thank you


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