Towards an Elastic Distributed SDN Controller
description
Transcript of Towards an Elastic Distributed SDN Controller
TOWARDS AN ELASTIC DISTRIBUTED SDN CONTROLLERAdvait Dixit, Fang Hao, Sarit Mukherjee, T.V. Lakshman, Ramana Kompella
Physical Network Infrastructure
SDN Control Plane
Distributed Control Plane
• Single point of failure• Performance bottleneck
Spatial Partitioning
Overload
Growing the Control Plane
Shrinking the Control Plane
Goals
•Build a distributed control plane which• Load balances• Grows• Shrinks
•This requires• Load estimation at controllers• Switch migration protocol
Naïve Switch MigrationSLAVEMASTER MASTERSLAVE
Role
Cha
nge
to
Mas
ter
Problem With Naïve Switch Migration
Packet-In
MASTER MASTERSLAVE SLAVE
Packet-OutRo
le C
hang
e to
Mas
ter
Packet-Out from Slave is dropped
Migration Protocol Requirements• Safety: Exactly 1 controller processes every message from the switch
• Liveness: For each switch, at least 1 controller is active at all times
• Openflow compliant
Flow-Add
Flow-DeleteFl
ow-R
emov
ed
4-Phase Switch Migration ProtocolMASTER SLAVE
Flow-Removed
EQUAL
Role
Chan
ge to
Mas
ter
SLAVE MASTER
Role
Chan
ge to
Equ
al
Barrier Request
Barrier Reply
Phase 1: Change from Slave to EqualPhase 2: Insert and remove dummy flowPhase 3: Flush in-
flight messagePhase 4: Change
from Equal to Master
A Mininet Testbed
Problem: Cannot generate sufficient traffic for a large distributed control plane
veth PairO
penv
Sw
itch
Ope
nvS
witc
h
veth Pair
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nvS
witc
h
veth Pair
Emulation Host
A Multi-Host Mininet TestbedO
penv
Sw
itch
Ope
nvS
witc
h
Ope
nvS
witc
h Ope
nvS
witc
h
Ope
nvS
witc
h
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nvS
witc
h
Emulation Host
Ope
nvS
witc
h
Ope
nvS
witc
h Ope
nvS
witc
h
GRE Tunnel`
GRE Tunn
el
GRE Tunnel
Emulation Host
Emulation Host
Evaluation
Evaluation
Next Step: ElastiCon
Physical Network Infrastructure
Core Controller Module
Application 1 Application 2
Core Controller Module
Application 1 Application 2
Distributed Data Store (e.g., Hazelcast)
Node 1
Load Measurements
Load Balance
Scale UpScale Down
Load Adaptation Decisions
Distributed SDN Control Plane
Node 2
Actions:• Migrate switch• Remove controller• Add controller
THANK YOU