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Attendre : Mitigating Ill Effects of Race Conditions in via Queueing Mechanism. Xiaoye Sun , Aproov Agarwal , T.-S. Eugene Ng Rice University. Race Conditions. What are these race conditions in OpenFlow ? Ill effects Controller workload Forwarding delay
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Attendre: Mitigating Ill Effects of Race Conditions in via Queueing Mechanism XiaoyeSun, AproovAgarwal, T.-S. Eugene Ng Rice University
Race Conditions • What are these race conditions in OpenFlow? • Ill effects • Controller workload • Forwarding delay • Cost of verification Controller pkt-in(2) pkt-in(1) flow-mod/pkt-out(1) flow-mod(2) flow-mod/pkt-out(1) flow-mod(1) flow-mod/pkt-out(2) 1 1 pkt-in(1) 1 2 2 Switch 1 Switch 2 Receiver Sender Entry pkt1
Attendre • Avoid unnecessary packet-in message • Queueing the packets if the switch is expecting corresponding flow-mods from the controller Controller pkt-in(1) flow-mod(1) flow-mod/pkt-out(1)’ 1’ 1 1 1 1 1 2 2 2 2 2 2 2 2 Switch 2 Switch 1 Receiver Sender Entry pkt1 WAIT Entry pkt1 Entry pkt1 WAIT Entry pkt1
Benefit on Verification • Verify a simple routing application with different number of packets and switches • State transition reduction can be several orders of magnitude.