Computational Intelligence on Automation Lab @ NCTU

Wei-Chu Lin, Gen-Hen Liu,

Kuan-Tsen Kuo, and Charles H.-P. Wen

Dept. Electrical and Computer EngineeringNational Chiao Tung University, Taiwan

DENDIST-FM: Flow Migration in Routing of

OpenFlow-based Cloud Networks

Outline

Introduction Related Work and Motivation Flow Migration Mechanism in SDN Experimental Result Conclusion

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About Cloud Datacenters (1/2)

For cloud datacenter networks (DCNs), researches frequently focus on issues of – Topology– Routing

Topology research targets DCN scalability– Porland [1]– Killer Fabric [2]– Jellyfish [3]

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About Cloud Datacenters (2/2)

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Routing research targets various performance perspectives and different applications– Hash-based Routing (HBR)– ENDIST– D2ENDIST

Evolutionary Software-Defined Networking (SDN) has emerged in cloud systems and resolves many networking problems

More About SDN

Software-defined networking (SDN) separates control plane and data plane of network– embrace more flexible routing on per-flow

basis Flows can be defined cross layers

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Layer-2 Layer-3 Layer-4

Outline

Introduction Related Work and Motivation Flow Migration Mechanism in SDN Experimental Result Conclusion

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Dynamic Routing in DCNs

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D2ENDIST is a layer-2 routing algorithm and consists of– Disjoint ENDIST routing – Reroute by dynamic weighting

SPB on Traditional Network

Path 1: A – 6 – 2 – 0 – 4 – 8 – E

Path 2: B – 6 – 2 – 0 – 4 – 8 – E

Path 3: A – 6 – 2 – 0 – 4 – 8 – F

Path 4: B – 6 – 2 – 0 – 4 – 8 – F

Path 5: C – 7 – 2 – 0 – 4 – 8 – E

Path 6: C – 7 – 2 – 0 – 4 – 8 – F

Path 7: C – 7 – 2 – 0 – 4 – 9 – G

Path 8: C – 7 – 2 – 0 – 4 – 9 – H

Path 9: A – 6 – 2 – 7 – C

Path 10: A – 6 – 2 – 7 – D

6 Over-Utilized Links:

6-2, 7-2, 2-0, 0-4, 4-8

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P.S. Definition of over-utilized links:No more than 6 in core-aggr. No more than 3 in aggr-edge.

0 1

2 3 4 5

6 7 8 9

A B HFEDC G

88

66

62

Core

Host

Aggr.

Edge

Path 1: A – 6 – 2 – 0 – 4 – 8 – E

Path 2: B – 6 – 2 – 0 – 4 – 8 – E

Path 3: A – 6 – 2 – 0 – 4 – 8 – F

Path 4: B – 6 – 2 – 0 – 4 – 8 – F

Path 5: C – 7 – 3 – 1 – 5 – 8 – E

Path 6: C – 7 – 3 – 1 – 5 – 8 – F

Path 7: C – 7 – 3 – 1 – 5 – 9 – G

Path 8: C – 7 – 3 – 1 – 5 – 9 – H

Path 9: A – 6 – 3 – 7 – C

Path 10: A – 6 – 3 – 7 – D

3 Over-Utilized Links:

6-2, 7-2, 2-0, 0-4 , 4-8,7-3

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0 1

2 3 4 5

6 7 8 9

A B HFEDC G

44

4 2 42

Core

Host

Aggr.

Edge

4 4

6 2

D2ENDIST on Traditional Network

How about D2ENDIST on SDN?

Motivation

SDN makes network control directly programmable across different layers–Routing can be more flexible–Path modification can be easier

Apply D2ENDIST to a OpenFlow-based cloud network–compare performances between dynamic-

routing and flow-control mechanisms

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Outline

Introduction Related Work and Motivation Flow-Migration Mechanism in SDN

–Traffic-aware Flow Migration (FM) Experimental Result Conclusion

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Dynamic Reroute in D2ENDIST

D2ENDIST applies reroute strategy to balance traffic load dynamically

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0 1

2 3 4 5

6 7 8 9

A B HFEDC G

5

4

3

2

3 2

3

3

3

0 1

2 3 4 5

6 7 8 9

A B HFEDC G

3

4

3

2

3 2

3

3

3

More Powerful!!Path 1: A – 6 – 2 – 0 – 4 – 8 – E

Path 2: B – 6 – 3 – 1 – 5 – 8 – E

Path 3: A – 6 – 2 – 0 – 4 – 8 – F

Path 4: B – 6 – 3 – 1 – 5 – 8 – F

Path 5: C – 7 – 2 – 0 – 4 – 8 – E

Path 6: C – 7 – 2 – 0 – 4 – 8 – F

Path 7: C – 7 – 3 – 1 – 5 – 9 – G

Path 8: C – 7 – 3 – 1 – 5 – 9 – H

Path 9: A – 6 – 2 – 7 – C

Path 10: A – 6 – 3 – 7 – D

1 Over-Utilized Link:

6-2, 7-3, 4-8

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0 1

2 3 4 5

6 7 8 9

A B HFEDC G

44

3 3 42

Core

Host

Aggr.

Edge

4 4

3 23

D2ENDIST in SDN

But that’s only theoretical. Why?

The shortest path algorithm (SPB) takes O(ns

2) time (ns: # switches)

D2ENDIST is based on all-pairs shortest path which takes O(ns

3)

Apply D2ENDIST to each flow, grows to

O(nf x ns3)=O(ns

5) if nf ~ ns2 (nf: # flows)

Therefore, propose “Traffic-aware Flow Migration”, with only O(ns

2)

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D2ENDIST Problem in SDN

Routing path: A-6-2-0-4-8-E

(1) Reroute path: A-6-2-1-4-8-E

(2) Reroute path: A-6-3-0-4-8-E

Example of Flow Migration

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0 1

2 3 4 5

6 7 8 9

A B HFEDC G

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9

4 6 4

4 43 26 45

5 5 3 5

0 1

2 3 4 5

6 7 8 9

A B HFEDC G

6

8

5 6 4

5 44 35 45

5 5 3 5

DENDIST-FM: FM + DENDIST

DENDIST-FM– DENDIST: disjoint paths (for balancing the

traffic load initially)– Flow Migration: dynamic reroute

Compare with D2ENDIST,–traffic-aware flow migration is a more

efficient for dynamic reroute

–Only requires O(ns2)

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Flowchart of Flow Migration

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D2ENDIST in SDN (Recap)

Path 1: A – 6 – 2 – 0 – 4 – 8 – E

Path 2: B – 6 – 3 – 1 – 5 – 8 – E

Path 3: A – 6 – 2 – 0 – 4 – 8 – F

Path 4: B – 6 – 3 – 1 – 5 – 8 – F

Path 5: C – 7 – 2 – 0 – 4 – 8 – E

Path 6: C – 7 – 2 – 0 – 4 – 8 – F

Path 7: C – 7 – 3 – 1 – 5 – 9 – G

Path 8: C – 7 – 3 – 1 – 5 – 9 – H

Path 9: A – 6 – 2 – 7 – C

Path 10: A – 6 – 3 – 7 – D

1 Over-Utilized Link:

6-2, 7-3, 4-8

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0 1

2 3 4 5

6 7 8 9

A B HFEDC G

44

3 3 42

Core

Host

Aggr.

Edge

4 4

3 23

DENDIST-FM in SDN

Path 1: A – 6 – 2 – 0 – 4 – 8 – E

Path 2: B – 6 – 3 – 1 – 5 – 8 – E

Path 3: A – 6 – 2 – 0 – 4 – 8 – F

Path 4: B – 6 – 3 – 1 – 5 – 8 – F

Path 5: C – 7 – 2 – 0 – 5 – 8 – E

Path 6: C – 7 – 2 – 0 – 4 – 8 – F

Path 7: C – 7 – 3 – 1 – 5 – 9 – G

Path 8: C – 7 – 3 – 1 – 5 – 9 – H

Path 9: A – 6 – 2 – 7 – C

Path 10: A – 6 – 3 – 7 – D

0 Over-Utilized Link: None!!!

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0 1

2 3 4 5

6 7 8 9

A B HFEDC G

43

3 3 33

Core

Host

Aggr.

Edge

4 4

3 23

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Outline

Introduction Related Work and Motivation Flow Migration Mechanism in SDN Experimental Result

– throughput comparison– reroute period

Conclusion

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Simulation Environment

NS2 provides source routing which can designate the routing path as flow-aware routing and thus is adopted in this work

A 3-tier fat-tree Topology–5 core-level switches–10 aggregate-level switches–50 edge-level switches–200 hosts–FTP traffic flows

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Throughput Comparison

Fat-Tree (5–10–50–200) + #flow=1000

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Reroute Period

Higher frequent polling better throughput– even close to the theoretical throughput of

D2ENDIST ( but with lower complexity)

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Outline

Introduction Related Work and Motivation Flow Migration Mechanism in SDN Experimental Results Conclusion

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Conclusion

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SDN demonstrates its potential to enable a better network for DCN–Dynamic routing like D2ENDIST can

perform better–But suffer from high complexity

DENDIST-FM integrates concepts of (1) disjoint path and (2) flow migration to yield–Better performance with –Lower complexity

Now, apply DENDIST-FM to Floodlight as future work

Thank you for listening!

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