Design and Implementation of a Load Balancing Algorithm for a Clustered SDN Control Plane - Slides

Design and Implementation of a Load Balancing Algorithm for a Clustered SDN Control Plane

Supervisor: Prof. Francesco Delli PriscoliTutor: Letterio Zuccaro

Candidate: Daniel Gheorghita

• Co-funded by the European Commission under the Seventh Framework Programme for Research(FP7)

• It promotes and supports Network Functions Virtualization(NFV)

• Partners: – Universities: Rome, Milan, Zurich– Companies: Intel, HP


2

3

Software Defined Networking

SDN• Decoupled control logic and forwarding logic• Logically centralized control• Network devices programmability using

APIs

OpenFlow• The most used standard and southbound API• Install flow entries in all network devices

– What to do when a specific packet arrives

OVSDB• Management and configuration of network

devices

Control Plane

Data Plane

Application Plane

API(e.g. OpenFlow)

API(e.g. REST)

OtherNetworkDevice

Application 1

Basic functionalities – Abstraction layer

Application 2


4

Software Defined Network: Example

Control Plane

Data Plane

Network Control Applications

Packet-in OpenFlow


Problem:Asynchronous messages

5

Software Defined Network: ExampleNetwork Control Applications

OpenFlow

Inconvenience: • overprovisioning

Control Plane

Data Plane


Load Balancing Algorithm. Dynamic Assignment

6

• Compute average CPU load of the entire cluster (AVG)• Divide controllers in overloaded and non overloaded• Divide the switches connected to the overloaded

controllers in classes of load• “Fill” every non overloaded controller up to AVG

– Best fit switches

• One cluster controller collects statistics from all controllers about the last interval of time(e.g. 4 sec) – Average CPU load – Number of messages received from every switch


The main steps:

Pagina 7

Load balancing algorithm: Running example

Sw8(15)

Sw6(30) Sw9(2

0)Sw10(1

0)

30: Sw3, Sw625: Sw715: Sw1, Sw2, Sw510: Sw4

46.25

Sw11(10)Sw1(1

5)

Sw2(15)

Sw5(15)

11.25 26.25

Sw3(30)

Sw7(25)

Sw4(10)

C1

Output:

{(Sw4, C1, C3)

, (Sw7, C2, C4)}


C2 C3 C4

Pagina 8

Migration for OpenFlow 1.0 and successive versions


Goal:• Avoid losing messages• Avoid duplicated responses

Problem:• In OF 1.0 the switch X sends

the packet-in messages to both controllers

X : A

X

BA

The main steps of the migration algorithm:

• Connect X to B and install a migration signaling entry in X

• Freeze roles(do not use the distributed cache content for X)• Change cache entry for X

• A removes the migration signaling entry from switch X

• Both controllers receive the notification and resume the use of the distributed cache

• Disconnect X from A

Do not reply

Do reply

X : B

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Why OpenDaylight controller:• Open platform• Developed under the Linux Foundation. • Supported by 44 members. Some of them: Brocade, Cisco, Dell,

HP, IBM, Intel, Juniper, Microsoft, Redhat, NEC, vmware, Oracle • Promising future. It aims to support multiple vendor southbound

interfaces– In the industry there is not fully agreement about the southbound protocol

• Supports clustering and has a distributed cache

My contribution in OpenDaylight:• Fairness in the initial (switch : controller) mapping• Dynamic load balancing service• Extended OVSDB


Implementation details


10

Testing environment

Mininet

S1 S2 Sn-1 Sn

H1 H2 Hn-1 Hn

A B

Open vSwitch

Network Control Application

Gigabit Switch

A B

Mininet

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The benefits of load balancing


Packet-in/s (104)

w/o load balancingwith load balancing

95-p

erc

resp

onse

tim

e(m

s)

6 - 2 imbalance

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Conclusion and future works

Conclusion: • Designed, implemented(in OpenDaylight) a load balancing

and switch migration algorithms• Developed support tools:

– a traffic generator application– a network control application– test scripts that measure the performances

Future works: • Deal with the failure of switches and controllers


13

Thank you for your attention!


Pagina 14

The benefits of multiple controller. Test scenarios


S1

H1

S1

3

H13

S2

H2

S1

2

H12

S1

4

H14

S2

6

H26

S1

5

H15

S2

5

H25

C1C2

S1

H1

S1

3

H13

S2

H2

S1

2

H12

S1

4

H14

S2

6

H26

S1

5

H15

S2

5

H25

C1 C2

S1

H1

S1

3

H13

S2

H2

S1

2

H12

S1

4

H14

S2

6

H26

S1

5

H15

S2

5

H25

C1

Single:

All:

Selective:

Pagina 15

The benefits of multiple controller. Results


Packet-in/s (104)

95-p

erc

resp

onse

tim

e(1

04 ) m

s SingleAll

Selective

Pagina 16

Tests: Migration timing


Aver

age

mig

ratio

n tim

e(m

s) AllSelective

Packet-in/s (104)

Pagina 17

Migration for OF 1.0 and successive versions


X’s Master Contr.

Controller B

Controller A

Connect

Switch X

X : A X : {A}

X : {A,B}Connect Ack

Start Migration & X-do not process

X : BChange map

Start Migration & X-do not process Ack

Install and Remove dummy-flowAdd dummy-flow

Barrier Request

Barrier Request

Remove dummy flowDummy-flow removeDummy-flow

remove

DisconnectDisconnect

Ack

End migration

X : {B}

X’s controllersMigrate X to B

Migration completed

Barrier Replay

Barrier Replay

Design and Implementation of a Load Balancing Algorithm for a Clustered SDN Control Plane - Slides

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