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“ Rate and distance fairness in OBS networks ”

“ Rate and distance fairness in OBS networks ”. Tananun Orawiwattanakul, Yusheng Ji. Topics. Optical Burst Switching (OBS) Networks Rate and Distance Fairness Preemption (RDFP) Simulation results Future works. First OBS commercial product (2006).

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“ Rate and distance fairness in OBS networks ”

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

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

  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. Optical Burst Switching (OBS)

  5. Challenge of OBS Dropped Offset Time5 DB5 C5 Offset Time1 C1 C2 C4 Control Channels C3 Offset Time4 DB4 Offset Time1 DB1 Offset Time3 Data Channels DB3 Offset Time2 DB2 Time T1 T2 T3 T4 T5 No Buffer -> High Losses Void ->Network cannot be fully utilized DB Data Burst C Burst Control Packet

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

  7. S1 S6 Path of Flow 1 S3 S4 S5 Path of Flow 2 S2 S7 S8 Distance fairness The loss probability of long-path flow tends to be higher than that of short path flow. It’s NOT FAIR!!! for me. ‘Distance fairness’ refers to the fair performance in terms of loss which respects to hop counts between the source and destination.

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

  9. Rate and Distance Fairness Preemption (RDFP) • Allocate bandwidth to each flow according to the max-min fairness. • 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). • 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. RDFP: Control Plane Ai FBCP FBCP Ti BBCP BBCP Core Switch 1 Core Switch 2 Core Switch N Egress Edge Switch Ingress Edge Switch

  11. RDFP: Burst Marking Rate Fairness Preemption (RFP) Ingress Edge Switch Input Rate Ti Ai Under-rate bursts (HIGH PRIORITY) Time when Ai ≤ Ti, all bursts are marked as “Under-rate bursts (HIGH PRIORITY)”

  12. RDFP: Burst Marking Rate Fairness Preemption (RFP) Ingress Edge Switch Input Rate Ai Over-rate bursts (LOW PRIORITY) Ti Under-rate bursts (HIGH PRIORITY) Time 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

  13. RDFP: Rate fairness preemption policy C1 Offset Time1 Over-rate Burst DB5 DB1 T1 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. Under-rate Burst Offset Time5 DB5 C2 C4 C5 Control Channels C3 Offset Time1 DB4 Offset Time1 Data Channels DB3 Offset Time1 DB2 Time T2 T3 T4 T5 If no original scheduled over-rate burst -> determine the DISTANCE FAIRNESS preemption policy.

  14. RDFP: Distance fairness preemption policy C1 Offset Time1 Under-rate Burst with Lower I DB5 DB1 T1 When contention occurs in core networks, the “Under-rate (HIGH PRIORITY)” burstscan preempt an original scheduled channel from bursts with lower of I. Under-rate Burst Offset Time5 DB5 C2 C4 C5 Control Channels C3 Offset Time1 DB4 Offset Time1 Data Channels DB3 Offset Time1 DB2 Time T2 T3 T4 T5 I = No of sucessful hops – Weight * (No. of remaining hops)

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

  16. RDFP: simulation results Normalized rate 1 = 16 Gbps. Input rate of each 3-hop and 4-hop flow = 0.05. Input rate of each 5-hop = 0.05-0.08.

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

  18. Q & A Thank you

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